Upload
tjhargraveklein
View
830
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Online lecture for chapter four (fats)
Citation preview
Fats
Chapter 4
What are fats?• Lipid molecules
– Carbon– Hydrogen– Oxygen
• Hydrophobic• Lipophilic
The terms fat and lipid will be used interchangeably in
this course.
Lipid Classification• Triglycerides
– Most common type of dietary lipid
• Phospholipids– Cell membranes– Water and
fat soluble– Help emulsify fat so it
stays dispersed in watery substances like blood.
• Sterols
Triglycerides
• Glycerol– Forms triglyceride
“backbone”– Three-carbon
molecule
• Three fatty acids– Can be of different
lengths
Triglyceride Functions
• Energy source– During rest and
exercise
• Energy reserve– 9 kcal/gram
• Provides protection– Cushioning– Insulator
(thermal/electrical)
• Vitamin carrier
Fatty Acids
• Carbon backbone• Length varies
– SCFA (< 6 carbons)– MCFA (6 to 10
carbons)– LCFA (> 10
carbons)
Fatty Acid Saturation• Saturated
– No double bonds– Saturated with
hydrogen– Solid at room
temperature• Unsaturated
– Mono and poly– Liquid at room
temperature
Fatty Acid Saturation
Omega Fatty Acids• Unsaturated• Their name is derived from position of first double
bond from methyl end– Omega 3, 6, 9 fatty acids
• Omega 3 and 6 are essential fatty acids– Linolenic and linoleic acids
• Form eicosanoids • If you would like additional information about
omega-3 fatty acids, refer to the article in the extra reading learning folder.
Hydrogenation• Addition of hydrogen
to unsaturated fat• Causes formation of
trans fats• Fats take on saturated
properties• Raises blood
cholesterol levels which is associated with increased risk for heart attack and stroke.
Phospholipids
• Structure– Glycerol backbone– Two fatty acids +
phosphate• Sources
– Egg yokes, soybeans, and peanuts
• Functions– Cell membranes– Emulsifiers– Transporters
Sterols
• Do not contain fatty acids
• Have ringed molecular structure
• Same physical properties as other fats
• Cholesterol is most common sterol
Artificial Fats
• Carbohydrate derived– Oatrim
• Protein derived– Simplesse
• Specialty fats– Olestra (Olean)– Salatrim (Benefat)
Photo © J. Helgason/ShutterStock, Inc.
Fat Intake
• No RDA or AI• 20–35% of total
calories– ~ 10% polyunsaturated– ~ 10% monounsaturated– < 10% saturated
• Avoid trans fats
Cholesterol
• Sources– Animals only
• Components– HDL– LDL– VLDL
• High levels of LDL increase risk for cardiovascular disease
Recommended Cholesterol LevelsYes, even athletes can have elevated
cholesterol levels!
Guidelines for Lowering Cholesterol• Limit saturated fat intake. (Choose oils over solid fat
most of the time)• Keep daily cholesterol intake < 300 mg. (Choose fats
from plant sources like canola and olive oil over animal sources like butter and whole milk)
• Limit trans fat intake. (Read the ingredient list. If partially hydrogenated oil is listed then the product contains trans fats.)
• Maintain active lifestyle.• Increase fruit and vegetable intake. (Make half your
plate fruits and vegetables!)
Bioenergetics of Fat
Interesting information but I do not expect you to commit it to memory
for this course.
Fat Intake: Before Exercise
• Fat Adaptation– Short-term– Long-term
• Single High-Fat Pre- Competition Meal
• Recommendations– Include fats but
keep to a minimum– Experiment with
different fat contentPhoto © Photos.com
Fat Intake: During Exercise
• Long-Chain Fatty Acids• Absorption is slow• Benefits questionable
• Medium-Chain Fatty Acids• Absorption is faster• Benefits questionable;
possible gastric upset• Recommendations
– Avoid fats during exercisePhoto © Photos.com
Fat Intake: After Exercise
• Normal dietary recommendations for fats apply- 20–35% fat content- Unsaturated fats
• Carbohydrates should predominate
• Consume post-exercise meal ASAP
Photo © Photos.com
FATS
• What can you take away from this chapter?
• What stands out for you?
• Are there any changes you would like to make to your sports nutrition diet now that you have this new information?