Energy Balance CH 10 - University of Massachusetts …4...Positive energy balance: consume more calories than expend, leads to fat storage, weight gain Negative energy balance: calorie

© 2012 Pearson Education, Inc.

Energy Balance

CH 10

© 2012 Pearson Education, Inc. Nutrition and You, 2e

Objectives

Explain the concept of a healthful weight and differentiate between overweight, underweight and obesity

Define and describe the concept of energy balance.

Discuss what happens to the body if too many or too few calories are consumed.

Define and describe the concepts of hunger, appetite, and satiety.

Explain how the body regulates hunger.

List three environmental factors that often contribute to higher body weight.

Describe a basic plan for healthy weight loss and/or weight gain.

Define and describe disordered eating.


How Do You Know If You’re at a Healthy

Weight?

A healthful body weight is a weight at which your risk

of developing weight-related health condidions is not

increased.

It is a range

Realistic

Overweight: 10-15 lbs above your ideal weight

Obese: 25-40+ lbs abobe your ideal weight


Weight Management

Weight management is maintaining your weight

within a healthful range.

Weight for height extremes can be dangerous.

Overweight/Obesity can increase your risk of

developing: HTN/stroke

Heart dx

Gallbladder dx

DM II

Osteoarthritis

Some cancers

Sleep apnea


Overweight in America

More than one-third of U.S. adults (35.7%) are obese.

Obesity-related conditions include heart disease, stroke, type 2 diabetes and

certain types of cancer, some of the leading causes of preventable death.

The estimated annual medical cost of obesity in the U.S. was $147 billion in

2008 U.S. dollars; the medical costs for people who are obese were $1,429

higher than those of normal weight.


How Do We Determine a Healthful

Weight?

BMI (Body Mass Index) is

a calculation of weight to

height.

<18.5 = Underweight

18.5-24.9 = Normal

weight

25-29.9 = Overweight

30 - 34.9= Class 1

obesity

35 - 39.9 = Class 2

obesity

40 + = Class 3 obesity

http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.pdf


Limitations of BMI

BMI is a screening tool only!! This means that it can not be used as a

diagnostic tool. Other factors MUST be taken into consideration.


Body Fat

Figure 10.2


Waist Circumference

Although waist circumference and BMI

often are interrelated, waist circumference

provides an independent prediction of risk

over and above that of BMI.

Waist circumference measurement is

particularly useful in patients who are

categorized as normal or overweight on the

BMI scale. At BMIs at 35 or over, waist

circumference has little added predictive

power of disease risk beyond that of BMI. It

is therefore not necessary to measure

waist circumference in individuals with

BMIs 35.

Figure 10.2

HIGH RISK

Men: >102 cm ( >40 in.)

Women: >88 cm ( >35

in.)


How Do we Measure body fat?

Skinfold thickness Bioelectrical Impedence Low electricity flows through the body lean

tissue has more H2O so is more condctive-

so based on the flow of elect: the amount of

lean tissue can be determined and therefore

the amount of fat tissue.


How Do we Measure body fat?

Dual-Energy X-Ray

Absorptiometry (DXA)

BodPod- based on air

displacement

Underwater weighing-

based on water

displacement


What Is Energy Balance and What

Determines Energy Needs?

Energy balance is calories in versus calories out

Positive energy balance: consume more calories

than expend, leads to fat storage, weight gain

Negative energy balance: calorie intake falls short

of needs, leads to weight loss

Energy needs are different for everyone

Energy needs comprised of:

Basal metabolism

Thermic effect of food

Physical activity


Energy Balance and Imbalances

Figure 10.5


ENERGY OUT: The Three Components of

Your Energy Needs

Figure 10.6

BMR- Minimum Amount

of energy needed to

keep you alive

TEF- Calories needed to

extract energy and

nutrtients from the food

we eat

PA- The most elastic

factor ie we have a lot

more control over this

number


Table 10.2 top

BMR


Table 10.2 bottom

BMR (cont)


Determining energy balance

Calculating your energy output:

Direct calorimetry : heat

Indirect calorimetry: oxygen consumption

Equations (EER)

Typically based on height/weight/age/gender/PA

See page 369 in your book

Adults 19 years and older - Men

EER = 662 - (9.53 x age [y]) + PA x { (15.91 x weight [kg]) + (539.6 x height [m])

}

Adults 19 years and older - Women

EER = 354 - (6.91 x age [y]) + PA x { (9.36 x weight [kg]) + (726 x height [m]) }


What Determines Energy Needs?

Physical activity will increase your energy needs

Sedentary people expend less than ½ energy of

BMR in physical activity

Very active athletes can expend twice BMR

Exercise causes small increase in energy

expenditure after activity has stopped


What Are the Effects of an Energy

Imbalance?

Too many calories can cause overweight

Excess calories stored as fat, regardless of source

Limited capacity to store glucose as glycogen

Can’t store extra protein

Unlimited capacity to store fat

Body contains about 35 billion fat cells, which

can expand


What Factors Are Likely to Affect Body

Weight? What and how often you eat, physiology, genetics,

environment all play role in weight management

Hunger and appetite affect what you eat

Appetite is psychological desire for food

Hunger is physiological need for food



Weight?

Physiological mechanisms help regulate hunger

Many hormones play role:

Ghrelin: produced in stomach when empty; increases

hunger

When fat stores increase, leptin in fat tissue signals brain

to decrease hunger and food intake.

Cholecystokinin: released when stomach is distended,

increasing feelings of satiation, decreasing hunger

Many people override feedback mechanisms, resulting

in energy imbalance



Weight?

Genetics partially determine body weight

Risk of becoming obese doubles if parents are

overweight, triples if obese, five times greater if

severely obese

Confirmed by studies of identical twins separated at

birth



Weight?

Genetic differences in level or function of hormones, such as high ghrelin or low leptin levels, increase obesity.

Genetic differences in nonexercise-associated thermogenesis (NEAT) (rate of energy expenditure in fidgeting, standing, other nonexercise movement)

“Set point” theory holds that body opposes weight loss and works to maintain a set weight



Weight?

We eat more (and more)

Increased availability of food-service establishments,

access to large variety of foods, larger portions

encourage people to eat more

We sit more and move less

Americans eating about 300 calories/day more than

in 1985

Labor-saving devices at work and home, sedentary

leisure activities (“screen time”) result in decreased

energy expenditure



Weight?

Environmental factors can increase appetite and

decrease physical activity

Environment of cheap and easily obtainable

energy-dense foods stimulate appetite

Gene-environment interaction: increases risk of

obesity in some people

We work more and cook less

About 1/3 calories come from ready-to-eat foods

prepared outside of home

Frequent dining out associated with higher BMI



Weight?

Gene-environment interaction: strongly increases risk

of obesity


Environmental Factors of Weight Gain

Figure 10.7


How Can You Lose Weight Healthfully?

National Institutes of Health: overweight

individuals should aim to lose about 10 percent

of body weight over 6-month period

Example: 180-pound person should lose

18 lbs/6 months = 3 lbs/month, ¾ lb/week

To lose 1 pound of body weight, need 3,500 calorie

deficit

Weight loss of ½ to 1 lb/week, need to decrease

daily calories by 250 to 500 calories



Successful long-term weight loss requires changes in

three areas: diet, physical activity, and behavior

Eat smart, because calories count: add satiation to low-

calorie meals by including higher-volume foods

Eat more vegetables, fruit, and fiber

Include some protein and fat in your meals

Protein increases satiety most

Fat slows movement of food from stomach into

intestines

Choose lean meat, skinless chicken, fish, nuts,

and unsaturated oils.


The Volume of Food You Eat

Figure 10.10




You can use MyPlate as a weight-loss guide:

High volume fruits, vegetables, whole grains, some

lean protein

Decrease fat

Ex. replace full-fat dairy with nonfat products

Decrease sugar

Ex. Water not soda



Move to lose

45 minutes or more per day of moderate-intensity activities can prevent becoming overweight and aid in weight loss

10,000 steps/day can reduce risk of becoming overweight

Break bad habits

Behavior modification: change behaviors that contribute to weight gain or impede weight loss

Techniques include keeping food log, controlling environmental cues that trigger eating, managing stress


Table 10.4


Food Log

Figure 10.11


Fad Diets Are the Latest Fad

Research shows that reduction of calories, not the composition of the diet, is effective in weight loss.

People who adhere the longest to weight-loss diets lose the most weight.

High drop-out rates for most extreme diets (Atkins and Ornish diets)

Beware of fad diet sensational claims and hype:

“It’s the carbs, not calories, that make you fat!”

Celebrity-endorsed miracle weight-loss products

“Natural” substances help lose weight without risk



How Can You Maintain Weight Loss?

Weight cycling is a common result of fad diets.

Weight loss can be maintained if keep healthy

habits used during weight loss

New, lower weight requires less calories to

maintain weight

45 minutes/day or more of moderate-intensity

physical activity recommended to maintain weight

loss


Three Pieces of the Long-Term

Weight Loss Puzzle

Figure 10.8


Extreme Measures for Extreme Obesity

BMI > 40 = extreme obesity

High risk of heart disease, stroke, dying

Requires aggressive weight-loss treatment, including

very-low-calorie diets, medications, and/or surgery

Very-low-calorie diets (< 800 calories) are short-term

and must be medically supervised.

Medications such as Orlistat can’t replace a lower

calorie diet, physical activity, and behavior

modification.


Extreme Measures for Extreme Obesity

Gastric bypass and gastric banding result in

higher levels of satiety and lower levels of hunger

Results in dramatic weight loss and reduction of

hypertension, diabetes, high blood cholesterol, and

sleep apnea

Risks include ulcers, gallstone, bleeding in stomach

and intestines

Liposuction is performed for cosmetic reasons

Fat may reappear, results not permanent

Complications such as infections, scars, swelling


Gastric Bypass and Gastric Binding

Misc 10.12


Research Studies and Experiments

Confirm Hypotheses

Experimental Research: involves at least two

groups of subjects

Experimental group: given a specific treatment

Control group: given a placebo (“sugar pill”)

Double-blind placebo-controlled experiment is “gold

standard”

Neither scientists nor subjects know which group

is receiving which treatment

All variables held the same and controlled for both

groups


What’s the Real Deal When It Comes to

Nutrition Research and Advice?

Newspaper headlines and television news items

report results of a single, recent research study.

Advice from authoritative health and nutrition

organizations is based on:

Consensus: the opinion of group of experts based

on collection of information


Evaluating Media Headlines with a

Critical Eye

Before making dietary and lifestyle changes based

on media reports, read with a critical eye and ask:

Was the research finding published in a peer-

reviewed journal?

Was the study done using animals or humans?

Do the study participants resemble me?

Is this the first time I’ve heard about this?

Wait until research findings are confirmed and

consensus reached by reputable health

organizations before making changes


Figure 1.7

Select subjects who are overweight

Randomly divide

subjects into 2

groups

One groups gets

treatment

One groups gets

placebo

Did experimental

group lose

weight?


How Can You Gain Weight Healthfully?

Gaining weight for the underweight is as

challenging as losing weight for the overweight

Need to add at least 500 calories to daily energy

intake for gain of 1 pound/week

Choose more energy-dense but nutritious foods from

each food group

Examples: waffle instead of toast, coleslaw

instead of cabbage

Eat more snacks during day to add more calories


What Is Disordered Eating and What Are

the Warning Signs?

Disordered eating: abnormal and potentially

harmful eating behaviors that do not meet

specific criteria for eating disorders

Eating disorders: psychological illnesses that

involve specific abnormal eating behaviors and

other factors

Most often adolescent or young adult white,

middle/upper-middle-class females, but increasing

in males, minorities, and other age groups



the Warning Signs?

Anorexia nervosa results from severe

calorie restriction

Self-starvation and excessive weight loss

Intense fear of being “fat”

Distorted body image: see themselves as

fat when underweight

Health consequences: electrolyte

imbalance (low blood potassium) can be

fatal

Drops in body temperature, lanugo,

decrease in heart rate and blood pressure,

osteoporosis



the Warning Signs?

Bulimia nervosa involves cycle of binge eating

and purging

Purging can include self-induced vomiting, excessive

exercising, strict dieting or fasting, abuse of diet pills,

laxatives, and diuretics

Vomiting can cause tears in esophagus, swollen

parotid glands, tooth decays, gum disease,

broken blood vessels in eyes

Potentially fatal electrolyte imbalance can also result

from bulimia



Factors That Contribute to Eating

Disorders

Figure 10.13


How Are Eating Disorders Treated?

Multidisciplinary teams is most effective approach

Psychological, medical, and nutrition professionals

Nutritional approaches include:

Identifying binge triggers, safe and unsafe foods,

hunger and fullness cues using food journals

Meal plans to ensure intake of adequate calories

and nutrients for anorexia nervosa and to help

avoid overeating with bulimia nervosa and binge

eating disorder

Recovery can be slow; no “quick fix”

Greater success if treated in early stages


Being a Healthful Weight is A LOT more

than the number on the scale Cardiovascular health

Free from disease

Free from injury

Flexible

Strong

Documents

Energy Balance CH 10 - University of Massachusetts …4...Positive energy balance: consume more calories than expend, leads to fat storage, weight gain Negative energy balance: calorie