Draft - University of Toronto T-Space€¦ · 47 SIT in a way that would favour fat loss following training. 48 49 Energy expenditure was similar between conditions, while fat oxidation

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The effects of a pre-exercise meal on post-exercise metabolism following a session of sprint interval training

Journal: Applied Physiology, Nutrition, and Metabolism

Manuscript ID apnm-2019-0510.R1

Manuscript Type: Article

Date Submitted by the Author: 16-Sep-2019

Complete List of Authors: Broad, Abigail; Wilfrid Laurier University Faculty of Science, Kinesiology and Physical EducationHowe, Greg; Wilfrid Laurier University Faculty of Science, Kinesiology and Physical EducationMcKie, Greg; Wilfrid Laurier University Faculty of Science, Kinesiology and Physical EducationVanderheyden, Luke; Wilfrid Laurier University Faculty of Science, Department of Kinesiology and Physical EducationHazell, Tom; Wilfrid Laurier University Faculty of Science, Kinesiology and Physical Education

Novelty bullets: points that summarize the key findings in

the work:

• Energy expenditure was similar between conditions, while fat oxidation was significantly greater in FED at 3 h post-exercise, • Appetite perceptions were significantly lower in FED, however energy intake was not different between conditions, • Current findings suggest that performing SIT in the fed or fasted state would not affect fat loss following training

Keyword:exercise metabolism < metabolism, fat metabolism < metabolism, energy balance < energy regulation, exercise performance < exercise, dietary intake < diet, lipid metabolism < lipid metabolism

Is the invited manuscript for consideration in a Special

Issue? :Not applicable (regular submission)

https://mc06.manuscriptcentral.com/apnm-pubs

Applied Physiology, Nutrition, and Metabolism

Draft

Running Head: Pre-exercise meal and sprint interval training

1

1 The effects of a pre-exercise meal on post-exercise metabolism following a session of sprint 2 interval training345 Abigail A. Broad, Greg J. Howe, Greg L. McKie, Luke W. Vanderheyden, Tom J. Hazell67 Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, 8 Ontario, Canada9

101112131415161718192021222324 Communicating Author:25 Tom J. Hazell, PhD26 Department of Kinesiology and Physical Education27 Wilfrid Laurier University28 75 University Ave W, Waterloo, Ontario, CANADA, N2L 3C529 Email: [email protected] Tel: 519-884-1970 x304831

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32 Abstract

33 Sprint interval training (SIT) has demonstrated reductions in fat mass through potential alterations

34 in post-exercise metabolism. This study examined whether exercising in the fasted or fed state

35 affects post-exercise metabolism following acute SIT. Ten active males performed a bout of

36 modified SIT (8 x 15 s sprints; 120 s recovery) in both a fasted (FAST) and fed (FED) state. Gas

37 exchange was collected through 3 h post-exercise, appetite perceptions were measured using a

38 visual analog scale, and energy intake was recorded using dietary food logs. There was no

39 difference in energy expenditure between conditions at any time point (p>0.329) or in total session

40 energy expenditure (FED: 514.8±54.9 kcal, FAST: 504.0±74.3 kcal; p=0.982). Fat oxidation 3 h

41 post-exercise was higher in FED (0.110±0.04 g·min-1) versus FAST (0.069±0.02 g·min-1;

42 p=0.013) though not different between conditions across time (p>0.340), or in total post-exercise

43 fat oxidation (FED: 0.125±0.04 g·min-1, FAST: 0.105±0.02 g·min-1; p=0.154). Appetite

44 perceptions were lower in FED (-4815.0±4098.7 mm) versus FAST (-707.5±2010.4 mm,

45 p=0.022), however energy intake did not differ between conditions (p=0.429). These results

46 demonstrate the fasted or fed state does not augment post-exercise metabolism following acute

47 SIT in a way that would favour fat loss following training.

4849 Energy expenditure was similar between conditions, while fat oxidation was significantly 50 greater in FED at 3 h post-exercise51 Appetite perceptions were significantly lower in FED, however energy intake was not 52 different between conditions53 Current findings suggest that performing SIT in the fed or fasted state would not affect fat 54 loss following training55

56 Keywords:

57 exercise metabolism; fat metabolism; energy balance; exercise performance; dietary intake; lipid

58 metabolism

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59 Introduction

60 Only 15% of Canadians are physically active enough to meet the guidelines of

61 accumulating 150 minutes of moderate-to-vigorous physical activity per week (Colley et al. 2011),

62 and an often-cited reason for this is perceived lack of time (Reichert et al. 2007; Stutts 2002).

63 However, the classic sprint interval training (SIT) protocol consists of four repeated 30 s “all-out”

64 sprints interspersed by 4 min of recovery, for a total exercise session of only 16 min (Gibala et al.

65 2012), which is a significantly reduced time commitment compared to endurance exercise which

66 typically consists of at least 30 min of continuous exercise (Gibala et al. 2006; MacPherson et al.

67 2011; Trapp et al. 2008). Despite the reduced time commitment, SIT has been shown to produce

68 similar physiological adaptations and health benefits to traditional endurance training (Boutcher

69 2011; Burgomaster et al. 2008; Burgomaster et al. 2005; Gibala et al. 2006; MacPherson et al.

70 2011), including reductions in fat mass (Hazell et al. 2014; MacPherson et al. 2011). Even the

71 modified SIT protocol of 8 x 15 sec sprints followed by 2 min of recovery that maintains the same

72 work:rest ratio has been shown to be successful in eliciting the same acute (Islam et al. 2017a) and

73 chronic (McKie et al. 2018; Yamagishi and Babraj 2017) responses as the traditional protocol.

74 Therefore, SIT can be thought of as a potential time efficient approach to reduce fat mass over

75 time. The potential mechanisms involved in this reduced fat mass include increases in excess post-

76 exercise oxygen consumption (EPOC) (Hazell et al. 2012; Islam et al. 2017a; Laforgia et al. 1997;

77 Townsend et al. 2013), fat oxidation (Boutcher 2011; Burns et al. 2012; Chan and Burns 2013;

78 Islam et al. 2017a), and appetite suppression (Hazell et al. 2017; Islam et al. 2017a; Williams et

79 al. 2013).

80 EPOC is the increased oxygen utilized post-exercise compared to resting levels (Gaesser

81 et al. 1984). Due to it’s supramaximal intensity, SIT has been shown to lead to elevated EPOC

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82 compared to control conditions (Burns et al. 2012; Chan et al. 2013; Hazell et al. 2012; Islam et

83 al. 2017b; Islam et al. 2017a; Townsend et al. 2014; Williams et al. 2013) and traditional endurance

84 exercise (Laforgia et al. 1997; Townsend et al. 2013). EPOC translates to elevated energy

85 expenditure, which would contribute to generating an energy deficit and potentially lead to a

86 decrease in fat mass. Fat oxidation has also been shown to be elevated during the recovery period

87 after a bout of moderate-intensity endurance exercise (Bielinski et al. 1985; Horton et al. 1998;

88 Kuo et al. 2005) and SIT can lead to similar (Williams et al. 2013), if not greater elevations (Burns

89 et al. 2012; Chan and Burns 2013; Islam et al. 2017a), which could contribute to decreases in fat

90 mass following training.

91 Another mechanism behind fat loss following SIT is appetite suppression. There is a

92 general consensus that moderate-intensity exercise does not increase energy intake with a recent

93 review suggesting a bout of SIT can lead to acute appetite suppression and subsequently similar

94 or lower energy intake compared to both control conditions and endurance exercise (Taylor et al.

95 2018). Therefore, decreased appetite perceptions as well as no changes in energy intake following

96 a bout of SIT can act to maintain the negative energy balance achieved through exercise to help

97 promote body fat loss.

98 It is apparent that the work done during a bout of SIT provides a stimulus that creates an

99 energy deficit through the mechanisms mentioned above, and thus it is important to investigate

100 how they can be altered in a way that would further enhance fat mass loss. One method of

101 achieving this is through manipulation of the pre-exercise meal. It has been well established that

102 ingesting a carbohydrate-rich meal prior to low-intensity endurance exercise decreases fat

103 oxidation during exercise (Coyle et al. 1997; Horowitz et al. 1997; Jeukendrup 2003; Spriet 2014;

104 Vieira et al. 2016). However, there is a lack of research on how feeding before exercise affects

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105 post-exercise metabolism, and of the evidence that does exist the results are inconclusive. Feeding

106 before exercise resulted in higher EPOC and post-exercise fat oxidation at 12 and 24 h post-

107 exercise (Paoli et al. 2011), however these findings may be due to a pre-exercise meal with high

108 fat content. In contrast, when the pre-exercise meal consisted of mainly carbohydrates, 24 h

109 accumulated fat oxidation was higher when exercising fasted (Shimada et al. 2013). Lack of

110 standardization in feeding protocols significantly limits the ability to interpret results and work

111 toward a conclusion as to how a pre-exercise meal influences post-exercise metabolism.

112 Additionally, there has been little work done on the effects of fasted and fed exercise on appetite

113 perceptions, however some research demonstrates exercising in the fed state enhances the appetite

114 supressing effects of exercise (Cheng et al. 2009; Deighton et al. 2012).

115 Overall, it is apparent that SIT influences EPOC, fat oxidation, and appetite perceptions in

116 a way that produces an energy deficit. The potential that these physiological responses can be

117 further altered through the ingestion of a pre-exercise meal indicates that SIT and energy intake

118 can potentially interact to enhance the energy deficit generated following exercise. However, the

119 aforementioned work studied endurance exercise only, thus more research is needed to examine

120 this effect on post-exercise metabolism following SIT. Therefore, we investigated the effects of a

121 pre-exercise meal on indices of performance, whole-body metabolism, and appetite following a

122 bout of modified SIT (8 x 15 sec sprints). We hypothesized that EPOC will be higher, fat oxidation

123 will be lower, and appetite perceptions will be further suppressed when SIT is performed after a

124 meal versus in the fasted state.

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125 Methods

126 Participants

127 Ten recreationally active males (age 18-24 y) were recruited to participate in this study.

128 Number of subjects needed was estimated based on power calculations using G Power as well as

129 based on previous studies using similar protocols and participants (Islam et al. 2017a). Participants

130 were non-smokers and healthy as assessed by the Physical Activity Readiness Questionnaire

131 (PAR-Q+) health questionnaire (Bredin et al. 2013). All participants were classified as physically

132 active (exercising ~3 times/week), and none were currently involved in a systematic training

133 program nor had been for at least 4 months prior to data collection. Participants were not taking

134 any dietary supplements at the time of the study. The experimental procedures were explained in

135 detail to all participants and all provided written informed consent before any data collection. The

136 Research Ethics Board at Wilfrid Laurier University approved this study in accordance with the

137 ethical standards of the 1964 Declaration of Helsinki.

138 Study Design

139 Participants completed two experimental sessions (~5 h each), in a randomized cross-over

140 design, during which oxygen consumption (V̇̇O2), carbon dioxide production (V̇CO2), heart rate

141 (HR), and appetite perceptions were measured. Experimental sessions consisted of one session

142 where exercise was performed in the fasted state (FAST), and one session where exercise was

143 performed in the post-prandial state (FED). Sessions were separated by at least 7 days and

144 administered in a counterbalanced randomized design to avoid learning effects. Participants were

145 instructed to refrain from physical activity, alcohol, and caffeine 24 h before each session.

146 Participants recorded their food intake the day before the first experimental session and replicated

147 this intake for the second session.

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148 Pre-Experimental Procedures

149 All participants completed a laboratory familiarization session (>2 days) before data

150 collection to introduce testing procedures and reduce any learning effects during subsequent

151 experimental sessions. Participants first had their height and weight measured using a ‘Health o

152 meter professional’ scale (Newell Brands Inc, GA, USA). Participants also had their V̇O2max

153 determined using a graded exercise test to exhaustion performed on a motorized treadmill (4Front,

154 Woodway, WI, USA). V̇O2 and V̇CO2 were measured continuously using an online breath-by-

155 breath gas collection system (MAX-II; AEI Technologies, PA, USA), which was calibrated with

156 gases of known concentrations and a 3-L syringe for flow. Following a 5-min treadmill warm-up,

157 each participant ran at a self-selected pace (5–6.5 m·h-1 or 8–10 km·h-1) with incremental increases

158 in grade (2%) applied every 2 min until volitional fatigue. HR was recorded beat-to-beat

159 throughout the test using an integrated HR monitor (FT1; Polar Electro, Que., Canada). V̇O2max

160 was taken as the greatest 30-s average in presence of a plateau in V̇O2 values (<1.35 mL·kg−1·min−1

161 increase) despite increasing workload, or 2 of the following criteria: (i) a respiratory exchange

162 ratio (RER) value >1.10, (ii) achievement of a HRmax (<10 beats·min−1 of age-predicted maximum

163 (220 − age), and/or (iii) voluntary exhaustion. After a 5-min cooldown followed by sufficient rest

164 (>20 min), participants completed a V̇O2 verification test as recommended by Poole & Jones

165 (2017), where the participant performed a constant work rate at ~110% of the work rate achieved

166 on the initial ramp test to verify that V̇O2max was obtained during the ramp test. After another

167 period of rest, participants practiced all-out running efforts on a specialized self-propelled

168 treadmill (HiTrainer, QC, Canada) on which all the exercise sessions would be performed.

169 Experimental Session

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170 Participants arrived at 0745 h after an overnight (>12 h) fast. They remained in the

171 laboratory for the next ~5 h (Figure 1). Participants were fitted with a HR monitor (Polar FT1,

172 Polar Electro, Que., Canada) and silicon facemask (Vmask, Hans Rudolph Inc., KS, USA) for the

173 continuous measurement of gas exchange (V̇̇O2 and V̇̇CO2) from 0745–0815 h. In the FED

174 session, participants were given a standardized breakfast at 0815 h and had 15 min to eat and 60

175 min to digest. The breakfast consisted of an appropriate amount of Clif bar(s) (7 kcal/kg, 0.14g/kg

176 fat, 1.3 g/kg carbohydrate, and 0.25 g/kg protein) and >500 mL of water. In the FAST session,

177 participants sat quietly for 75 min. From 0930-0955 h participants completed the SIT session.

178 Gas exchange was measured during exercise, as well as the 30 min following exercise. The

179 participants in the FAST session then consumed the same standardized breakfast, while

180 participants in the FED session sat quietly. For the ~3.5 h following exercise, participants sat

181 quietly while gas exchange was measured for 15 min at every hour post-exercise. Finally, appetite

182 perceptions were measured when participants were still fasted, and then subsequently pre-exercise,

183 immediately post-exercise, as well as 30 min, 1 h, 2 h, and 3 h post-exercise.

184 Exercise Protocol

185 All exercise protocols began with a 5-min warm-up at a self-selected pace followed by a

186 16 min SIT session and 4 min cool-down. The warm-up and cool-down were performed on a

187 motorized treadmill (Woodway 4Front), while SIT was performed on a specialized self-propelled

188 treadmill (HiTrainer). The SIT session consisted of 8 x 15 sec all-out sprints interspersed with 2

189 min of recovery (Islam et al. 2017a; McKie et al. 2018). The treadmill interface provides audio

190 prompting to begin and stop running bouts and verbal encouragement was provided for the entirety

191 of all sprints.

192 Performance

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193 Customized treadmill software recorded the speed (m·s−1) attained during each sprint in

194 0.5 s intervals. Performance was measured in terms of peak speed, average speed, minimum speed,

195 and fatigue index, during the SIT session. Fatigue index was calculated using the following

196 formula:

197 FI (%) = [(peak speed – minimum speed) / peak speed] x 100

198 Reproducibility was calculated using the following formula:

199 Reproducibility (%) = (average speed / peak speed) x 100

200 V̇O2

201 V̇̇O2 (L·min−1) was recorded as 30-s averages over the entire duration of each gas collection

202 period. V̇O2 during exercise (excluding warm-up and recovery) was taken as the average V̇O2

203 over the duration of each SIT protocol (16 min). Post-exercise V̇O2 was determined by plotting

204 the average V̇O2 at each time-point (30 min post-exercise and the last 15 min of the first, second,

205 and third h post-exercise) and calculating the area under the curve (AUC) using the trapezoid

206 method. The rate of V̇O2 was multiplied by the duration of each distinct gas collection period to

207 obtain total V̇O2 (L). The immediate 30 min post-exercise measurement was included as part of

208 the first post-exercise hour V̇O2 calculation. Total V̇̇O2 during the 30 min resting measure was

209 extrapolated to a duration of 3 h and subsequently subtracted from the total post-exercise V̇̇O2 in

210 order to calculate EPOC. Total EE (kcal) was calculated from total V̇O2 (L) during and post-

211 exercise, assuming 5 kcal per litre O2 consumed given the limitations of using RER during

212 exhaustive, non-steady-state exercise (Laforgia et al. 1997).

213 Fat Oxidation

214 The rate of fat oxidation was calculated during each hour post-exercise using the following

215 formula (Péronnet and Massicotte 1991):

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216 Fat oxidation = 1.695 × V̇̇O2 – 1.701 × V̇̇CO2

217 where fat is in g·min−1 and V̇̇O2 and V̇̇CO2 are in L·min−1. The 30 min immediately post-exercise

218 gas exchange measure was not included in the calculation for fat oxidation for the first hour post-

219 exercise as CO2 production was still elevated due to hyperventilation. Consequently, the 15 min

220 gas exchange measure at the end of the first hour post-exercise was averaged and extrapolated for

221 the full hour.

222 Appetite Perceptions

223 Subjective appetite and satiety ratings were assessed in the fasted state, pre-exercise,

224 immediately post-exercise, as well as 1, 2, and 3 h post-exercise using the Visual Analogue Scale

225 (VAS). Questions on the VAS pertain to participants’ feelings of fullness (i.e. “How full do you

226 feel?”), hunger (i.e. “How hungry do you feel?”), and food consumption (i.e. “How much do you

227 think you can eat?”). Values for satiety and fullness were inverted, and then averaged together

228 with values for hunger and prospective energy intake to obtain an overall appetite score. AUC

229 was then calculated using the trapezoid method using changes in overall appetite perceptions

230 relative to baseline values.

231 Energy Intake

232 Participants recorded their energy intake via dietary food logs for the day prior to, day of,

233 and day after both experimental sessions. Participants were instructed to replicate their food intake

234 the day prior to each experimental session. Energy intake was then to be compared between

235 sessions for the remainder of the day following the experimental session as well as the next day to

236 examine potential differences in subsequent energy intake between feeding or fasting conditions.

237 Additionally, each day of energy intake was analyzed to determine the percent calories contributed

238 from each macronutrient (carbohydrates, protein, and fat). Food logs were analyzed using the

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239 United States Department of Agriculture (USDA) food composition database, which provides

240 caloric and macronutrient values for various food products.

241 Statistical Analysis

242 Two-way repeated measures ANOVA was used to determine differences in performance

243 variables (session (2) x sprint (8)), heart rate (session (2) x time (6)), RER (session (2) x time (6)),

244 energy expenditure (session (2) x time (5)), fat oxidation (session (2) x time (5)), appetite

245 perceptions (session (2) x time (7)), energy intake (session (2) x day (3)), and macronutrient

246 composition (session (2) x day (3)). Paired t-tests were used to determine differences between

247 sessions in total energy intake, total post-exercise fat oxidation, and index of decrease in appetite

248 perceptions. Additionally, a paired t-test was also used to compare energy intake and

249 macronutrient composition the day before the experimental trial of both sessions. All statistical

250 analyses were performed on Prism statistics software (GraphPad Software, San Diego, CA), and

251 Bonferroni post hoc analyses were used when necessary. Significance was set at p<0.05, and all

252 data is presented as means±SD.

253 Effect sizes were calculated using Cohen’s d for all t-tests and post hoc comparisons,

254 whereas partial eta-squared ( was used to calculate Cohen’s ƒ for interaction and main effects ƞ2𝑝)

255 of all two-way ANOVAs using the following equation:

256 Cohen’s ƒ = √ƞ2

𝑝

(1 ― ƞ2𝑝)

257 For Cohen’s d, 0.2 indicated a small effect size, 0.5 indicated a medium effect size, and 0.8

258 indicated a large effect size, whereas for Cohen’s ƒ, 0.1 indicated a small effect size, 0.25 indicated

259 a medium effect size, and 0.4 indicated a large effect size.

260 Results

261 Participant Characteristics

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262 Participants were 21.3±2.0 y with a V̇̇O2max of 48.31±3.49 mL·kg-1·min-1, a body mass of

263 83.37.8 kg, a height of 180.25.2 cm, and a body mass index (BMI) of 25.7±2.9 kg/m2. All

264 participants were healthy as assessed by the PAR-Q+ and classified as recreationally active based

265 on the Godin leisure scale.

266 Performance

267 There was no session x time interaction for any performance variable (p>0.450). There

268 were also no main effects of condition (p=0.442, ƒ=0.07, no effect) or sprint bout number for

269 fatigue index (p=0.212, ƒ=0.27, medium). However, there was a significant main effect of sprint

270 bout number for peak speed (p<0.001, ƒ=0.67, large), minimum speed (p=0.001, ƒ=0.43, large),

271 and average speed (p<0.001 ƒ=0.64, large), which is depicted in Figure 2.

272 There was no significant session x time interaction for heart rate (p=0.369, ƒ=0.23, small)

273 and no main effect of session (p=0.980, ƒ<0.01), though there was a significant main effect of time

274 (p<0.001, ƒ=2.5, large) where heart rate was significantly higher (p<0.001, d>2.55, large) during

275 exercise (FAST: 14017 bpm, FED: 14910 bpm) than all other time points (FAST: rest = 6410

276 bpm, 0.5 h = 9814 bpm, 1 h = 857 bpm, 2 h = 799 bpm, 3 h = 708 bpm, FED: rest = 649

277 bpm, 0.5 h = 1029 bpm, 1 h = 8117 bpm, 2 h = 7311 bpm, 3 h = 6712 bpm). Additionally,

278 heart rate was significantly elevated (p<0.031, d>0.54, medium) at 30 min (FAST: 9814 bpm,

279 FED: 1029 bpm), 1 h (FAST: 857 bpm, FED: 8117 bpm), and 2 h post-exercise (FAST: 799

280 bpm, FED: 7311 bpm) compared to rest (FAST: 6410 bpm, FED: 649 bpm).

281 Oxygen Consumption

282 There was no significant difference in total oxygen consumed between sessions (p=0.579,

283 d=0.18, no effect; FAST: 100.8±14.9 L O2, FED: 103.0±11.0 L O2). Additionally, there was no

284 significant session x time interaction for V̇̇O2 (p=0.363, ƒ=0.25, medium). There was no main

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285 effect of session (p=0.705, ƒ=0.02, no effect), though there was a significant main effect of time

286 (p<0.001, ƒ=0.21, small) where V̇̇O2 was significantly greater (p<0.001, d>1.06, large) during

287 exercise (FAST: 28.3±4.4 L O2, FED: 28.8±4.2 L O2) than all other time points (FAST: rest =

288 8.6±1.1 L O2, 1 h 23.8±2.8 L O2, 2 h = 20.3±4.4 L O2, 3 h = 19.8±3.8 L O2; FED: rest = 8.6±0.7

289 L O2, 1 h = 25.8±3.3 L O2, 2 h = 20.7±2.7 L O2, 3 h = 19.1±2.1 L O2). Additionally, V̇̇O2 during

290 rest was significantly lower than all time points (p<0.001, d>5.63, large), and 1 h post-exercise

291 (FAST: 23.8±2.8 L O2, FED: 25.8±3.3 L O2) was significantly (p<0.001, d>2.78, large) greater

292 than 2 h ( FAST: 20.3±4.4 L O2, FED: 20.7±2.7 L O2) and 3 h post-exercise (FAST: 19.8±3.8 L

293 O2, FED: 19.1±2.1 L O2). Finally, there was no significant difference in EPOC between sessions

294 (p=0.379, d=0.29, small; FAST: 12.3±5.7 L O2, FED: 14.2±5.5 L O2) (Figure 3a).

295 Energy Expenditure

296 There was no significant difference in total energy expended between sessions (p=0.798,

297 d=0.18, no effect; FAST 504.0±74.3 kcal, FED: 514.8±54.9 kcal) (Figure 3b). Additionally, there

298 was no significant session x time interaction for energy expenditure (p=0.408, ƒ=0.25, medium)

299 and no main effect of session (p=0.751, ƒ=0.13, small). There was a significant main effect of

300 time (p<0.001, ƒ=3.78, large) (Figure 3c) where energy expenditure was significantly greater

301 (p<0.001, d>1.27, large) during exercise (FAST: 141.3±21.8 kcal, FED: 143.0±20.8 kcal) than all

302 other time points (FAST: rest = 43.1±5.6 kcal, 1 h = 119.1±14.2 kcal, 2 h = 101.3±22.0 kcal, 3 h

303 = 98.6±18.9 kcal, FED: rest = 42.9±3.5 kcal, 1 h = 127.9±16.9 kcal, 2 h = 101.7±14.9 kcal, 3 h =

304 94.3±11.7 kcal). Additionally, energy expenditure at rest was lower (p<0.001, d>5.63, large)

305 compared to all time points. Energy expenditure was significantly greater (p<0.001, d>2.78, large)

306 at 1 h post-exercise (FAST: 119.1±14.2 kcal, FED: 127.9±16.9 kcal) than 2 h (FAST: 101.3±22.0

307 kcal, FED: 101.7±14.9 kcal) and 3 h post-exercise (FAST: 98.6±18.9 kcal, FED: 94.3±11.7 kcal).

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308 Fat Oxidation

309 When fat oxidation was averaged across the total post-exercise period, there was no

310 significant difference (p=0.198, d=0.44, small) between sessions (FAST: 0.105±0.04 g·min-1 vs

311 FED: 0.123±0.02 g·min-1) (Figure 4a). There was no significant session x time interaction for fat

312 oxidation (p=0.063, ƒ=0.38, medium) (Figure 4b), however there was a main effect of time

313 (p<0.001, ƒ=0.69, large) where 1 h (0.1320.05 g·min-1), 2 h (0.1210.04 g·min-1), and 3 h

314 (0.0900.03 g·min-1) post-exercise were significantly greater than rest (0.0650.02 g·min-1)

315 (p<0.004, d>1.18, large). Additionally, 1 h post-exercise (0.1320.05 g·min-1) was significantly

316 higher than 2 h (0.1210.04 g·min-1) and 3 h post-exercise (0.0900.03 g·min-1) (p<0.001, d>2.36,

317 large), and 2 h post-exercise (0.1210.04 g·min-1) was significantly greater than 3 h post-exercise

318 (0.0900.03 g·min-1) (p=0.002, d=2.21, large).

319 There was a significant session x time interaction for RER (p=0.022, ƒ=0.39, medium)

320 (Figure 4c). In both sessions, RER was significantly higher (p<0.001, d>4.46, large) during

321 exercise (FAST: 1.29±0.10, FED: 1.29±0.20) than all other time points (FAST: rest = 0.87±0.04,

322 0.5 h = 0.81±0.09, 1 h = 0.73±0.05, 2 h = 0.88±0.03. 3 h = 0.86±0.04, FED: rest = 0.87±0.19, 0.5

323 h = 0.85±0.04, 1 h = 0.74±0.03, 2 h = 0.81±0.02, 3 h = 0.78±0.01). In the FAST session, RER at

324 1 h post-exercise (0.73±0.05) was significantly lower (p<0.001, d=4.42, large) than rest

325 (0.87±0.04), 2 h post-exercise (0.88±0.03), and 3 h post-exercise (0.86±0.04). In the FED session,

326 RER at 1 h post-exercise (0.74±0.03) was significantly lower (p=0.008, d>0.62, medium) than rest

327 (0.87±0.19) and 0.5 h post-exercise (0.85±0.04), and 3 h (0.78±0.01) was significantly lower

328 (p=0.050, d=5.21, large) than rest (0.87±0.19). Additionally, RER at 3 h post-exercise was

329 significantly lower (p=0.040, d=2.44, large) in the FED session (0.78±0.01) compared to the FAST

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330 session (0.86±0.04). There was no significant difference (p=0.135, d=0.49, small) in average post-

331 exercise RER between sessions (FAST: 0.82±0.02 vs FED: 0.80±0.04).

332 Appetite Perceptions

333 There was no significant difference (p=0.759, d=0.1, no effect) in absolute values for

334 overall appetite perceptions between sessions at baseline (FAST: 75.811.1 mm vs FED:

335 77.819.3 mm). There was a significant interaction effect (session x time) for overall appetite

336 perceptions (p<0.001, ƒ=0.80, large) (Figure 5a). Relative to baseline values, overall appetite

337 perceptions were lower (p<0.004, d>1.28, large) at pre-exercise (-38.6±23.3 mm), post-exercise (-

338 38.4±20.1 mm), 30 min post-exercise (-35.5±26.2 mm), and 1 h post-exercise (-19.8±15.5 mm) in

339 the FED session. In the FAST session, overall appetite perceptions were only lower (p<0.001,

340 d=1.89, large) than baseline at 1 h post-exercise (-34.5±23.8 mm), and 1 h post-exercise was

341 significantly lower than all other time points (p<0.001, d>0.81, large). Appetite perceptions

342 immediately post-exercise (69.4±29.2 mm) were significantly lower (p=0.003, d=0.67, medium)

343 than pre-exercise (84.6±13.5 mm) in the FAST session, but not the FED session (pre-exercise:

344 39.2±17.9 mm vs post-exercise: 39.4±15.3 mm; p=0.977, d=0.01, no effect).

345 FED had lower appetite than FAST at pre-exercise (39.2±17.9 mm vs. 84.6±13.5 mm),

346 immediately post-exercise (39.4±15.3 mm vs. 69.4±29.2 mm), and 30 min post-exercise

347 (39.4±15.3 mm vs. 79.5±21.6 mm; p<0.001, d>1.38, large). There were no significant differences

348 (p>0.077, d<0.82, large) in appetite between sessions at 1 h (FED: 58.0±13.3 mm, FAST:

349 41.3±16.1 mm), 2 h (FED: 71.1±10.5 mm, FAST: 62.9±16.8 mm) or 3 h (FED: 83.6±7.4 mm vs.

350 79.4±11.6 mm) post-exercise. The AUC for overall appetite perceptions was significantly lower

351 (p=0.022, d=0.87, large) in the FED session (-4815.0±4098.7 mm) compared to the FAST session

352 (-707.5±2010.4 mm) (Figure 5b).

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353 Energy Intake

354 There was no significant difference (p>0.238, d<0.14, no effect) in energy intake (FAST:

355 2187.8263.4 kcal vs FED: 1953.2526.3 kcal) or macronutrient composition (FAST: protein =

356 20.585.65%, fat = 30.576.06%, carbohydrate = 49.026.55% vs FED: protein = 23.188.55%,

357 fat = 29.395.46%, carbohydrate = 47.699.89%) on the day before the experimental session

358 between sessions.

359 Additionally, there was no significant session x day interaction for energy intake (p=0.429,

360 ƒ=0.23, small). There was no significant main effect of session (p=0.960, ƒ=0.02, no effect),

361 though there was a significant main effect of day (p=0.013, ƒ=0.56, large) where energy intake

362 was significantly higher (p=0.013, d=0.42, small) on the day of the experimental session

363 (2644.3859.7 kcal) than the day before the experimental session (1953.2526.3 kcal). There was

364 no significant interaction (p>0.205, ƒ=0.13, small) or main effect of session (p>0.341, ƒ=0.11,

365 small) or day (p>0.081, ƒ=0.23, small) for macronutrient composition (Table 1).

366

367 Discussion

368 This study examined the effects of a pre-exercise meal before a bout of modified SIT on

369 indices of performance, whole-body energy metabolism, appetite, and energy intake. Whether SIT

370 was performed in the fed or fasted state had no effect on sprint performance, energy expenditure,

371 or fat oxidation during exercise. Post-exercise energy expenditure and fat oxidation remained

372 similar between conditions for 3 h. Overall appetite perceptions were significantly lower in FED

373 vs FAST, however, energy intake was not significantly different. Overall, these post-exercise

374 measurements have the potential to be important to fat loss following training, however these

375 results suggest that fasting or feeding prior to performing a bout of SIT has little influence.

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376 No differences in performance were apparent whether performing the modified SIT session

377 in the fasted or fed state. In contrast, previous research regarding aerobic exercise generally finds

378 that feeding 2-4 h before exercise improves time trial and time to exhaustion performance by ~2%

379 and ~20%, respectively (Chen et al. 2009; Ormsbee et al. 2014; Sherman et al. 1991), which is

380 likely due to increased glycogen availability (Coyle et al. 1985). While an overnight fast

381 significantly reduces glycogen stores in the liver, and consequently has a negative impact on

382 endurance performance (Coyle et al. 1985), the modified SIT protocol relies on the PCr system

383 more than muscle and liver glycogen for energy (Bogdanis et al. 1996; Bogdanis et al. 1998).

384 Considering the pre-exercise meal would act to replenish glycogen stores with no effect on the PCr

385 system, and sprints rely heavily on PCr for energy production, it is logical that performing SIT in

386 either the fed or fasted state would have no influence on sprint performance.

387 Oxygen consumption, and thus energy expenditure, was elevated compared to rest through

388 the entire 3 h post-exercise period, indicating that significant EPOC was present in response to a

389 modified SIT protocol (Islam et al. 2017a). The EPOC was 12.3 and 14.1 L in FAST and FED,

390 respectively, in line with previous research with similar populations (Chan and Burns 2013; Islam

391 et al. 2017a; Townsend et al. 2014; Williams et al. 2013). Total energy expenditure in both FAST

392 and FED (504.0 and 504.8 kcal, respectively) was also similar to energy expenditure observed in

393 previous studies with similar participants and protocols (Chan and Burns 2013; Islam et al. 2017a).

394 However, whether SIT was performed in either the fed or the fasted state had no influence on

395 EPOC or energy expenditure in the post-exercise period. This indicates that regardless of whether

396 SIT is performed in the fed or fasted state, the increases in energy expenditure are similar, therefore

397 energy expenditure would not contribute to greater fat loss following training in either state. The

398 lack of differences in energy expenditure could be due to the relatively minor contribution of

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399 EPOC – 12.3 L (12.2%) and 14.2 L (13.8%) in FAST and FED, respectively – to total oxygen

400 consumption (Laforgia et al. 1997). Although the contribution of EPOC may seem small, oxygen

401 consumption was still elevated 2.6 L (14.6%) in FAST and 1.9 L (11.3%) in FED 3 h post-exercise

402 compared to rest. Consequently, an additional 12.6 and 9.6 kcal, in FAST and FED respectively,

403 was being expended 3 h post-exercise. It has been shown that SIT can produce significant EPOC

404 up to 9 (Laforgia et al. 1997) and even 24 h post-exercise (Hazell et al. 2012; Sevits et al. 2013) in

405 similar populations, suggesting the duration of EPOC observed in the current study may continue

406 beyond 3 h post-exercise could have important implications for weight loss and potential

407 differences between FAST and FED.

408 Fat oxidation was elevated by >60% compared to rest during the post-exercise period,

409 which is in line with previous research regarding fat oxidation and SIT (Burns et al. 2012; Chan

410 and Burns 2013; Islam et al. 2017a; Williams et al. 2013). Although research shows that exercising

411 in the fasted state leads to greater fat oxidation during endurance exercise than the fed state (Coyle

412 et al. 1997; Horowitz et al. 1997; Jeukendrup 2003; Spriet 2014; Vieira et al. 2016), it is not

413 possible to measure fat oxidation during or immediately after SIT with gas exchange due to

414 hyperventilation and increased VCO2 (Hazell et al. 2014). Additionally, research has shown that

415 at exercise intensities above 60% VO2max there are no differences in fat oxidation between exercise

416 performed in the fed or fasted state (Bergman and Brooks 1999; Vieira et al. 2016). Therefore, as

417 SIT is a supramaximal exercise regimen that relies mainly on carbohydrate oxidation for energy

418 production (Brooks and Mercier 1994), it is likely that there would be no differences in fat

419 oxidation during exercise when performing it in the fed or fasted state.

420 It is important to note that though fat oxidation appeared similar between FED and FAST

421 throughout the 3 h post-exercise period (interaction not significant), it was tending toward

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422 significance with a p-value of 0.063 and had a moderate-high effect size (ƒ=0.38). This was likely

423 driven by the difference in fat oxidation at 3 h post-exercise, with FED oxidizing 0.041 g·min-1

424 more than FAST, which had a large effect size (f=1.53). Consequently, 6.6 g of fat was oxidized

425 in FED whereas only 4.1 g of fat was oxidized in FAST, producing a difference of 2.5 g of fat over

426 the hour. Although energy expenditure was similar, 63% of energy was derived from fat in FED,

427 whereas fat only contributed 37.4% to energy expenditure in FAST. However, this difference may

428 be due to the standardized breakfast which was carbohydrate dense, consequently increasing

429 carbohydrate oxidation and suppressing fat oxidation (Whitley et al. 1997). At 3 h post-exercise,

430 participants in the fed condition ate ~ 4.5 h ago, whereas participants in the fasted condition ate

431 only ~ 2.5 h ago, thus a more recent meal may have acted to suppress fat oxidation in FAST. This

432 could have important implications for fat loss following SIT if individuals are able to delay food

433 consumption >3 h post-exercise. However, whether it is practical or feasible for individuals to

434 wait more than three hours after exercise to consume a post-exercise meal is debateable.

435 Prolonging a post-exercise meal to >3 h post-exercise may be possible, as appetite has been

436 shown to be significantly suppressed following a bout of SIT (Deighton et al. 2013; Hazell et al.

437 2017; Islam et al. 2017a). Additionally, research regarding the effects of fed and fasted exercise

438 on appetite perceptions have also noted the appetite suppressing effects of exercise in either state

439 (Cheng et al. 2009; Deighton et al. 2012; Gonzalez et al. 2013). In line with these propositions,

440 appetite perceptions in FAST and FED at 0.5 h post-exercise did not increase from pre-exercise

441 perceptions like they do in control or moderate-intensity continuous exercise conditions (Islam et

442 al., 2017b), demonstrating appetite suppression.

443 Appetite perceptions returned to baseline in both FAST and FED by 2 h post-exercise,

444 however the index of decrease was significantly greater in FED than FAST, indicating that more

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445 time was spent with appetite perceptions below baseline values. This was evident through appetite

446 perceptions being lower than baseline from pre-exercise through to 2 h post-exercise in FED,

447 whereas appetite percpeitons were only lower than baseline at 1 h post-exercise in FAST,

448 illustrating a greater suppression of appetite when exercising in the fed state. This indicates that

449 the pre-exercise meal may interact with the exercise bout to maintain appetite-suppression for

450 longer into the post-exercise period, leading to overall greater suppression of appetite experienced

451 in the FED.

452 Appetite perceptions returned to baseline levels in both conditions at 2 h post-exercise.

453 This is important, as it is likely that participants would have eaten at this time if they were

454 permitted to. If a meal was consumed at 2 h post-exercise, then the elevated fat oxidation observed

455 at 3 h post-exercise in the FED would have been suppressed and no longer significant. Therefore,

456 appetite perceptions at 2 h post-exercise suggest that individuals may not be able to wait >3 h

457 before consuming a post-exercise meal, and consequently would not benefit from the elevated fat

458 oxidation at this time.

459 Ideally, for differences in appetite perceptions to play a role in fat loss following exercise

460 training, there would need to be a link between perceptions and energy intake such that an energy

461 deficit is induced. However, there were no differences in energy intake between conditions on

462 either the day before, day of, or day following exercise, therefore suggesting that decreased

463 appetite perceptions in FED would not contribute to an increased energy deficit and consequently

464 fat loss following continued training. These discrepant findings are potentially due to the

465 difficulties in measuring free-living energy intake, as the subjective nature of the food logs used

466 to measure energy intake can lead to large variability in energy intake data between and within

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467 participants, thus potentially providing inconsistent and inaccurate results (Dhurandhar et al.

468 2015).

469 Although energy intake was not affected throughout the remainder of the day following

470 exercise, it is possible that due to differing appetite perceptions during the experimental session,

471 administration of an ad libitum meal post-exercise may have led to significant findings related to

472 energy intake between conditions. However, in studies utilizing an endurance exercise protocol

473 followed by an ad libitum lunch, there were no significant differences in energy intake whether

474 exercise was performed in the fed or fasted state, despite differences in appetite perceptions

475 (Deighton et al. 2012; Farah et al. 2013; Gonzalez et al. 2013). Overall, despite appetite

476 perceptions being significantly lower following exercise in the fed state, there are no differences

477 in energy intake that would contribute to a greater energy deficit post-exercise, and consequently

478 greater fat loss following continued training.

479 The overall lack of difference in post-exercise metabolism following a bout of SIT in either

480 the fasted or fed state indicates that performing exercise in either state would lead to a similar

481 energy deficit. Therefore, superior fat loss following continued training in either the fasted or fed

482 state would not occur. However, it is important to note that the current study was acute in nature,

483 and it is possible that continued training could lead to varying adaptations between FAST and FED

484 that would contribute to altered fat loss. For example, enzymes such as citrate synthase, β-

485 hydroxyacyl-CoA dehydrogenase (βHAD), and plasma membrane fatty acid-binding protein

486 (FABPpm), have been shown to be elevated following continued sprint interval training

487 (Burgomaster et al. 2008; Burgomaster et al. 2005a; Jacobs et al. 1987; Rodas et al. 2000; Talanian

488 et al. 2007). The current study did not examine activity of these enzymes, and therefore it is

489 possible that performing SIT in the fasted or fed state may alter these adaptations in a way that

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490 would favour greater fat loss following training without any acute changes in fat oxidation

491 immediately post-exercise (<3 h). However, previous research has shown that 6 weeks of both

492 fasted and fed HIIT led to significant fat loss in overweight women, with no difference between

493 groups (Gillen et al. 2013). Although a similar training study has not been done using a SIT

494 protocol, based on the findings of the current study, it is likely that similar results would occur.

495 Although the current study provides important insights to the effects of fed state on post-

496 exercise metabolism important to fat loss, there are some limitations that must be considered. First,

497 energy intake was measured via self-reported food logs. Although participants were instructed on

498 how to measure and record food intake accurately, it is difficult to determine the extent to which

499 the food log accurately represents the actual energy intake of the participant. Second, the

500 administration of the standardized breakfast post-exercise in the fasted condition confounds the

501 results of post-exercise fat oxidation. Consequently, the difference observed in fat-oxidation 3 h

502 post-exercise is likely due to the post-exercise meal rather than the fed state exercise was

503 performed in. However, providing the standardized breakfast to the fasted condition post-exercise

504 was chosen because it was considered impractical not to allow food intake for > 5 h in the

505 laboratory while performing strenuous exercise. Finally, as the current study involved healthy and

506 active young males, it is difficult to generalize findings to other populations (ie. females, unfit,

507 overweight, sedentary, etc.).

508

509 Conclusion

510 In summary, there are no differences in energy expenditure or energy intake following a

511 bout of SIT in either the fasted or fed state. Although fat oxidation and appetite perceptions were

512 altered following exercise in a way that would favour fat loss following training in the fed

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513 condition, it is difficult to determine if these changes are meaningful enough to produce

514 significantly more fat loss following continued training. These findings have important

515 implications for the general fitness community, as it is often recommended to perform fasted

516 exercise to improve fat loss. While evidence suggests that this may be the case for moderate-

517 intensity endurance exercise, the current study shows that fasted SIT would provide little benefit

518 to fat loss when performing high-intensity exercise. This indicates that individuals would be able

519 to perform SIT in either the fed or fasted state, whichever is most comfortable for them, without

520 sacrificing potential benefits to fat loss.

521

522 Acknowledgements

523 The authors thank the participants for their involvement in the study. This work was

524 partially supported by an NSERC Undergraduate Research Scholarship to A.A.B and Ontario

525 Graduate Scholarships to A.A.B and GLM.

526

527 Conflict of Interest

528 The authors have no conflicts of interest to report.

529

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642 Interval Training on Energy Intake: A Systematic Review and Meta-Analysis. J. Obes. 2018(6903208).

643 Townsend, J.R., Stout, J.R., Morton, A.B., Jajtner, A.R., Gonzalez, A.M., and Wells, A.J. 2013. Excess

644 post-exercise oxygen consumption (EPOC) following multiple effort sprint and moderate aerobic exercise.

645 Kinesiology, 45(1): 16+.

646 Townsend, L.K., Couture, K.M., and Hazell, T.J. 2014. Mode of exercise and sex are not important for

647 oxygen consumption during and in recovery from sprint interval training. Appl. Physiol. Nutr. Metab.

648 39(12): 1388-94.

649 Trapp, E.G., Chisholm, D.J., Freund, J., and Boutcher, S.H. 2008. The effects of high-intensity intermittent

650 exercise training on fat loss and fasting insulin levels of young women. Int. J. Obes. 32(4): 684-91.

651 Vieira, A.F., Costa, R.R., Macedo, R.C., Coconcelli, L., and Kruel, L.F. 2016. Effects of aerobic exercise

652 performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-

653 analysis. Br. J. Nutr. 116(7): 1153-1164.

654 Vollaard, N.B., Metcalfe, R.S., and Williams, S. 2017. Effect of Number of Sprints in a SIT Session on

655 Change in VO2max: A Meta-analysis. Med. Sci. Sports Exerc. 49(6): 1147-1156.

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656 Whitley, H.A., Humphreys, S.M., Samra, J.S., Campbell, I.T., Maclaren, D.P., Reilly, T., and Frayn, K.N.

657 1997. Metabolic responses to isoenergetic meals containing different proportions of carbohydrate and fat.

658 Br. J. Nutr. 78(1): 15-26.

659 Williams, C.B., Zelt, J.G., Castellani, L.N., Little, J.P., Jung, M.E., Wright, D.C., Tschakovsky, M.E., and

660 Gurd, B.J. 2013. Changes in mechanisms proposed to mediate fat loss following an acute bout of high-

661 intensity interval and endurance exercise. Appl. Physiol. Nutr. Metab. 38(12): 1236-44.

662 Yamagishi, T. and Babraj, J. 2017. Effects of reduced-volume of sprint interval training and the time course

663 of physiological and performance adaptations. Scand. J. Med. Sci. Sports, 27(12): 1662-1672.

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665 Figure 1: Experimental session timeline666667 Figure 2: A: Peak speed across sprint bouts. *, significantly greater than sprints four, five, six, 668 seven, and eight. B: Average speed across sprint bouts. *, significantly lower than sprint 1. ^, 669 significantly lower than sprint 2. C: Minimum speed across sprint bouts. *, significantly lower 670 than sprint 1. D: Fatigue index across sprint bouts.671672 Figure 3: A: Total litres of O2 consumed and EPOC (checkered areas) over then entire 3 h post-673 exercise period. B: Total energy expenditure across the duration of the session in both 674 experimental conditions.. C: Changes in energy expenditure across all time points in both 675 experimental conditions. *, significantly greater than rest. #, significantly lower than 1 h. ^, 676 significantly greater than all other time points.677678 Figure 4: A: Total fat oxidation across the duration of the post-exercise period in both 679 experimental conditions. B: Changes in fat oxidation across all time points in both experimental 680 conditions. *, significantly greater than rest. ^, significantly lower than 1 h post-exercise. C: 681 Respiratory exchange ration across time in both experimental conditions. *, significantly greater 682 than all other time points. ^, significantly lower than rest. #, significantly lower than 2 h and 3 h 683 post-exercise. $, FED significantly lower than FAST.684685 Figure 5: A: Changes in overall appetite perceptions across all time points relative to baseline. * 686 significant difference between FED and FAST. ^, significantly lower than baseline. B: Index of 687 decrease in overall appetite perceptions in both conditions. *, p<0.05 vs. FAST.

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Figure 1: Experimental session timeline

380x137mm (72 x 72 DPI)

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Draft1 2 3 4 5 6 7 8

0

2

4

6

8

Sprint

Peak

spe

ed (m

•s)

FASTFED

Peak Speed*

1 2 3 4 5 6 7 80

2

4

6

8

Sprint

Ave

rage

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ed (m

•s) FAST

FED

Average Speed

*^

1 2 3 4 5 6 7 80

1

2

3

4

5

Sprint

Min

imum

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ed (m

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FED

Minimum Speed

* *

1 2 3 4 5 6 7 80

20

40

60

80

Sprint

Fatig

ue In

dex

(%)

FASTFED

Fatigue Index

a) b)

c) d)

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DraftFAST FED

0100200300400500600700800

Condition

Ener

gy E

xpen

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re (k

cal) FAST

FED

REST EXERCISE 1 h 2 h 3 h0

50

100

150

200

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FASTFED

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40

60

80

Condition

O2 (

L)a) b) c) Page 34 of 38



DraftFAST FED

0.00

0.05

0.10

0.15

0.20

Tota

l pos

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ricse

fa

t oxi

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n (g⋅m

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)

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0.05

0.10

0.15

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Fat o

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tion

(g⋅m

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FASTFED*

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REST EX 0.5 h 1 h 2 h 3 h0.50.60.70.80.91.01.11.21.31.41.5

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BASE PRE POST 0.5 h 1 h 2 h 3 h-100-80-60-40-20

020406080

100

Time

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ll ap

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e (m

m)

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*

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Table 1: Energy intake (kcal) and macronutrient composition (%) across days and between conditions

Day 1 (before)

Day 2 (exercise)

Day 3 (after)

Energy intake (kcal) 2187.8263.4 2519.8741.0 2196.0638.5PRO (%) 20.65.7 19.96.9 18.17.0FAT (%) 30.66.1 32.43.8 33.77.7

FAST

CHO (%) 49.06.6 49.06.9 48.411.1

Energy intake (kcal) 1953.2526.3 2644.3859.7* 2347870.0PRO (%) 23.28.6 17.45.6 19.16.6FAT (%) 29.45.5 27.85.8 33.99.7

FED

CHO (%) 47.79.9 55.98.6 47.212.7NOTE: *: significantly different from Day 1 (p<0.05)

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Draft - University of Toronto T-Space€¦ · 47 SIT in a way that would favour fat loss following training. 48 49 Energy expenditure was similar between conditions, while fat oxidation