Chapter 9

Designing Weight Management and Body Composition

Programs

Health and longevity are threatened when a person is either overweight or underweight.

Overweight and obesity increase one’s risk of developing serious cardiovascular, pulmonary, and metabolic diseases and disorders.

Individuals who are underweight may have a higher risk than others of cardiac, musculoskeletal, and reproductive disorders.

Definitions and Classifications

• Obesity: excessive amount of body fat relative to body weight; body mass index (BMI) at least 30.0 kg/m2

• Overweight: BMI between 25 and 29.9 kg/m2

• Underweight: BMI less than 18.5 kg/m2

• To identify children and adolescents who are overweight, the 85th and 95th percentile BMI values are used; cutoffs for age and sex are still under discussion.

Trends in Overweight and Obesity (see also Table 9.1, p.233)

• According to World Health Organization (2007):• More than 1.6 billion adults are overweight.• Over 400 million are obese. • By the year 2015 the number of overweight people

globally is estimated to increase to 2.3 billion.• Adults: Prevalence of overweight and obesity varies

among countries, depending in part on the level of industrialization.• In the U.S., 34% are obese (BMI > 30 kg/m2), • 2 out of 3 are overweight (BMI = 25-29.9 kg/m2)

Trends in Overweight and Obesity• Children and adolescents (6-19 years): Prevalence at risk

for overweight (BMI of 85th-95th percentile) in Canada and the United States ranges from 29% to 35% .• Since 1980 the number of overweight American children

has doubled, and the number of overweight American adolescents has tripled.

Types of Obesity• Fat distribution (pattern) in the body may be more

important than total body fat for determining one’s risk of disease.• Abdominal fat is strongly associated with diseases such

as CHD, diabetes, hypertension, and hyperlipidemia• Android: -Upper body obesity - typically male pattern;

apple shape; localization of excess body fat mainly in the upper body; upper-body obesity (most men)

• Gynoid: Lower body obesity - typically female pattern; pear shape; localization of excess body fat mainly in the lower body; lower-body obesity (most women)

Causes of Overweight and Obesity• Physical inactivity• Overeating• Positive energy balance: energy consumed (food and beverages)

exceeds energy expended (exercise plus resting energy expenditure)• For every 3500 kcal of excess energy accumulated, 1 lb (0.45 kg) of

fat is stored in the body.• Will be stored or lost depending on direction of energy balance

(positive or negative)• A negative energy balance is produced when the energy expenditure exceeds

the energy input. People can accomplish this by reducing the food intake or increasing the physical activity level.

Basal Metabolic Rate (BMR)• Energy need and expenditure are measured in kilocalories

(kcal). A kilocalorie is defined as the amount of heat needed to raise the temperature of 1 kg (2.2 lb) of water 1° C.• BMR = Measure of the minimal energy (kcal) needed to

maintain basic and essential physiological functions• Varies according to age, gender, body size, and body

composition• For assessment of BMR, the individual needs to be rested

and fasted and should be in a controlled environment.

Resting Metabolic Rate (RMR, REE)

• Practical alternative to BMR• Defined as energy required to maintain essential

physiological processes in a relaxed, awake, and reclined state• Also known as resting energy expenditure (REE)

Total Energy Expenditure (TEE)

• TEE = (BMR or RMR) + dietary thermogenesis (i.e.,

energy needed for digesting, absorbing, transporting, and metabolizing foods) + physical activity• The gold standard for measuring TEE is the

doubly labeled water (with deuterium and oxygen-18) method. This method is expensive and requires considerable expertise and specialized equipment.• TEE estimated via age- and gender-specific

prediction equations (see table 9.3)

Energy Expenditure• Energy expenditure during basal, resting, or

activity states can be measured in laboratory settings through indirect calorimetry.• Energy expenditure is estimated from oxygen

utilization. Every liter of oxygen consumed per minute yields approximately 5 kcal (see table 9.2).• One MET equals the relative rate of oxygen

consumption of 3.5 ml·min−1 for each kilogram of body weight (3.5 ml·kg−1·min−1)• For specific physical activities, energy expenditure

is typically expressed in METs (see chapter 4 and appendix E.4)

Energy Expenditure - RMR Regulation

• Thyroxine is extremely important in regulating RMR. Underproduction of thyroxine can reduce RMR 30% to 50%.• Growth hormone, epinephrine, norepinephrine,

and various sex hormones may elevate RMR as much as 15% to 20%. (increase during exercise and may be responsible for the elevation in RMR after cessation of exercise.)

Energy Storage – Obesity Concerns

• Obesity is associated with increases in both the number and size of fat cells

• Obese individuals have a higher fat cell number (hyperplasia) and size (hypertrophy)

• Hyperplasia occurs rapidly during the first year of life and again during adolescence but remains fairly stable in adulthood, except in cases of morbid obesity.

• Epidemiological studies suggest that weight gain in the first six months of life is primarily a gain in fat and that this time period is critical for development of obesity

• Caloric restriction and exercise are effective in reducing hypertrophy size but not hyperplasia in adults

Energy Storage – Obesity Concerns

• Approximately 25% of the variability among individuals in absolute and relative body fat is attributed to genetic factors, and 30% is associated with cultural (environmental) factors

• Hill and Melanson (1999) suggested that the major cause of obesity in the United States is our environment.

• Over the past 30 years, the U.S. population has been exposed to an environment that strongly promotes the consumption of high-fat, energy-dense foods (increased energy intake) and reliance on technology that discourages physical activity and reduces the amount of physical activity (decreased energy expenditure) needed for daily living.

Weight Management Principles and Practices • Key components: proper nutrition and physical activity• Weight management does not always mean weight loss;

client may need to gain weight.• The best method for negative energy balance is a

combination of dietary restriction and exercise.• To gain weight, client must maintain positive energy

balance.• “Weight Management Principles” (p. 239, next slide)

summarizes principles and practices underlying the design of weight management programs.

Weight Management Principles

Physically Active Lifestyle• Daily aerobic exercise

• strength and flexibility exercises• increased participation in recreational activities

such as bowling, golf, tennis, and dancing• increased physical activity in the daily routine at

home and work through restricting use of labor-saving devices such as escalators, power tools, automobiles, and home and garden appliances.

Healthful Eating

• Consume a variety of nutrient-dense foods within and among the basic food groups.• Limit intake of saturated and trans fats,

cholesterol, added sugars, salt, and alcohol.•Meet recommended intakes within energy

needs by adopting a balanced eating pattern.

Weight Management

• To maintain healthy body weight, balance calories from foods and beverages with calories expended.• To prevent gradual weight gain, make small

decreases in food and beverage calories and increase physical activity.

Physical Activity• Engage in at least 30 minutes of moderate-intensity

physical activity, above ADLs and occupational requirements, on most days of the week.• Greater health benefits are obtainable by engaging

in more vigorous or longer bouts of physical activity.• To manage and maintain healthy body weight,

engage in approximately 60 minutes of moderate- to vigorous-intensity exercise, most days of the week, and eat within caloric intake requirements.

Physical Activity (continued)

• To sustain weight loss, participate in at least 60 to 90 minutes of daily moderate-intensity physical activity and eat within caloric intake requirements

• Achieve physical fitness by including• cardiovascular conditioning, • stretching exercises for flexibility, and• resistance exercises or calisthenics for muscle

strength and endurance.

Food Groups to Encourage• Sufficient amount of fruits and vegetables while staying

within energy needs (recommended for a reference 2000-calorie intake)

• Selections from all five vegetable subgroups several times a week • Daily:• Variety of fruits and vegetables • At least 3 ounces of equivalents of whole-grain products with

the rest of the recommended grains from enriched or whole-grain products

• 3 cups per day of fat-free or low-fat milk or equivalent milk products

Carbohydrates (CHOs)

• Select fiber-rich fruits, vegetables, and whole grains.• Select foods and beverages with little added sugar

or caloric sweeteners.• Limit consumption of sugar- and starch-containing

foods and beverages.

Sodium and Potassium• Consume less than 2,300 mg (approx. 1 tsp. of salt) of

sodium per day.• Choose and prepare foods with little salt.• Consume potassium-rich foods such as fruits and

vegetables.

Alcoholic Beverages• Those who drink should practice responsible drinking:

one or fewer drinks per day for women and two or fewer drinks per day for men.

• Alcohol consumption should be completely avoided in many situations where the individual cannot control their consumption (ex. Pregnancy, Rx’s)

Well-Balanced Nutrition• The Institute of Medicine [IOM], (2002), recommends

following percentage contribution, by food group, for a well-balanced nutritional plan for adults:• 45% to 65% of their calories from CHOs• 20% to 35% of their calories from fat • 10% to 25% of their calories from protein

• Since 1971, the average daily energy intake increased ≈7% for men and 21% for women. This increase in calorie intake was attributed primarily to increases in the relative and absolute carbohydrate intake. The relative carbohydrate intake increased from 42% to 49% in men and from 45% to 51.6% in women.

• Also, the relative dietary fat increase for men and women was between 5 and 7 g/day, and dietary protein slightly decreased.

Carbohydrates• Major types:• Simple CHOs: simple sugars found in fruits, berries, some

vegetables, table sugar, and honey• Complex CHOs: found in many plant-based foods, whole grains,

and low-fat dairy products• Experts tout health benefits of consuming wide range of CHOs

with emphasis on fruits, vegetables, whole grains, and low-fat dairy products.

• To maintain and replenish glycogen stores, you need a daily CHO intake of• 7 to 8 g·kg–1 of body weight if you engage in low-intensity,

moderate-duration physical activity. • 7 to 12 g·kg–1 of body weight if you engage in high-intensity or

long-duration exercise.

Carbohydrates• The glycemic index (GI) has been used to classify

carbohydrate-containing foods. • The GI is a measure of the body’s glycemic response (i.e.,

increase in blood glucose and insulin following consumption) to various foods.

• To obtain the GI value of a food, the glycemic response of that food is compared with the glycemic response of glucose (GI = 100).

• Generally, refined grain products and potatoes have a high GI (>60), legumes and unprocessed grains have a moderate GI (40-60), and non-starchy fruits and vegetables have a low GI (<40).

• The AHA, American Diabetes Association, and American Dietetic Association do not endorse using the GI for disease prevention and treatment

Protein• Approximately 10% to 25% of the daily caloric intake should

be protein. • The diet should include sources of the essential amino acids

needed for protein synthesis.≈≈• In general, daily protein requirement of the body is ≈ 0.8

g·kg–1 of body weight.• For endurance athletes recommended intake is 1.2 to 1.4

g·kg–1 of body weight.• Strength-trained athletes may need as much as 1.7 g·kg–1 of

body weight.• Too much protein in the diet causes dehydration due to

excessive production of urea, which must be eliminated in the urine

Fats• Some dietary fat is needed to supply fatty acids and to

absorb fat-soluble vitamins.• Approximately 20% to 35% of the daily energy intake

should come from fat; however, fats must be chosen wisely. • To promote weight loss and to reduce serum

cholesterol level, limit these intakes:• saturated fat and trans fatty acids (<7% of total

calories) • total fat (25% to 35% of total calories)• cholesterol (<200 mg per day if one has elevated

LDL; otherwise < 300 mg/day)

Vitamins

• No need to supplement if diet is balanced.• Those restricting food intake to lose weight

or make weight, may benefit from supplementation.• Supplementation is beneficial only for

those who are deficient in one or more vitamins.• See also Table 9.5, p. 242

Minerals• Physically active individuals, particularly

vegetarians, may need to supplement iron and zinc.• Iron requirements for endurance athletes (e.g.,

distance runners) are increased by 70% (ACSM 2009).• For athletes with eating disorders, amenorrhea,

and risk for early osteoporosis, 1,500 mg of elemental calcium and 400-800 IU of vitamin D per day are recommended (ACSM 2009).

Vitamin and Mineral Supplementation Facts• Vitamin B12 supplementation does not increase

muscle growth or strength.• Carnitine (a vitamin-like compound)

supplementation does not facilitate loss of body fat.• Chromium supplementation does not increase fat-

free mass or decrease body fat.• Boron supplementation does not increase serum

testosterone or fat-free mass.• Magnesium supplementation does not improve

muscle strength.

Water• Athletes and physically active individuals need to• hydrate before exercise,• drink fluids during exercise, and• rehydrate immediately after exercise.

• The amount and rate of fluid replacement depend on the athlete’s sweat rate, exercise duration, and opportunities to drink.• Guidelines for maintaining hydration before, during,

and after exercise have been developed by the ACSM and the National Athletic Trainers’ Association (next slide)

Prehydration, Hydration, and Rehydration• Guidelines for hydration:• About 4 hours before exercise, drink 5 to 7 ml/kg of

body weight of water or a sport beverage.• Replace fluids depending on sweat rate, exercise

duration, and opportunities to drink.• Drink at least 6 ounces of fluid every 15 to 20 minutes.• Consume drinks containing CHO (6-8%) and sodium

when endurance exercise is more than 1 hour.• Drink at least 16 ounces of fluid for every pound of

body weight lost during exercise.

Designing Weight-Management Programs: Preliminary Steps

In designing weight management programs for weight loss or weight gain, you need to set body weight goals and assess the calorie intake and expenditure for your clients

1. Set body weight goals.2. Assess calorie intake and energy expenditure.3. Design weight-loss program inclusive of caloric

restriction plus exercise program.4. Work closely with a licensed nutritionist or

registered dietitian when planning diets for your clients. (See example of process, next slides , pp. 251-2.)

Steps for Designing a Weight Loss Program

Steps for Designing a Weight Loss Program

Weight-Loss Diets• Low-carbohydrate (carb) iso-caloric diets (e.g.,

Atkins) result in rapid short-term weight loss in obese adults; shown to improve triglyceride and HDL-C levels.• High-protein or low-carb diets result in great 3-

to 6-month weight losses; high-protein diets increase satiety and may thereby reduce daily caloric intake.• Long-term effect of macronutrient restrictive

diets is not yet known.

Weight-Loss Diets (continued)

• Research shows that weight loss depends on calorie intake and not on the macronutrient composition of the diet.• An effective strategy for reducing energy (calorie) intake

is to eat less refined, processed food as well as less saturated and trans fat.• A balanced diet contains adequate amounts of good

sources of carbohydrate, protein, and fat (table 9.8).• Healthy Eating Pyramid: (figure 9.2)• Foundation of daily physical activity and weight control • Recommendations for food choices that promote health and

weight control

Exercise for Weight Loss

• For health benefits according to ACSM (2008):• At least 30 minutes of moderate-intensity (3-6 METs) activity

at least 5 days a week or • 20 minutes of vigorous-intensity (>6.0 METs) for a minimum of

3 days a week

• Alternatively, according to the 2008 Physical Activity Guidelines for Americans, health benefits are achieved with• 150 to 300 minutes a week of moderate-intensity (3-6 METs)

exercise or• 75 to 150 minutes a week of vigorous-intensity (≥ 6.0 METs)

exercise.

Exercise for Weight Loss (for summary see Table 9.9, next slide)

• Preventing weight gain:• Moderate-intensity physical activity between 150 and 250

minutes a week (ACSM 2009)• 45 to 60 minutes of moderate- to vigorous-intensity activity on

most, preferably all, days (IOM, 2002)• For children and adolescents, at least 60 minutes of moderate-

to vigorous-intensity physical activity daily

• Specific amount of physical activity needed to prevent weight regain is uncertain.

• About 60 minutes a day of walking at a moderate intensity is associated with weight maintenance (ACSM 2009).

• At least 60 minutes, but preferably 80 to 90 minutes, of moderate-intensity physical activity and exercise recommended per day (IOM 2002).

Table 9.9

Benefits of Exercise in Weight Management• Increases energy expenditure • Helps create a negative energy balance for

weight loss• Promotes fat loss and preservation of LBM• Maintains or slows down FFM loss resulting

from weight loss via diets only• Helps maintain weight loss after dieting• Increases RMR

Types of Exercise in Weight Management• Aerobic exercise is effective for weight loss, fat

loss, and long-term weight management.• Resistance training increases muscle mass and

REE; it does not produce much weight loss. • Resistance training may increase fat loss when

combined with aerobic exercise.

Exercise Intensity and Weight Management• Weight loss and fat loss are positively related to

weekly energy expenditure. • At a constant energy expenditure, total fat

oxidation is higher during low-intensity compared to high-intensity exercise.• Exercise duration may be key for fat loss.• Most obese clients prefer a slower pace and

low- to moderate-intensity exercise.

Designing Weight-Gain Programs• First, rule out the possibility that diseases and

psychological disorders associated with malnutrition are causing low weight level.• A caloric excess of 2,800 to 3,500 kcal is required to gain

1 pound.• Adding 400 to 500 kcal to the estimated daily caloric

needs can result in a gain of 1 pound a week.• Adjust caloric intake to cover exercise energy

expenditure.

Exercise Prescription for Weight Gain• Prescribe resistance training to increase muscle

size.• A high-volume resistance training program

maximizes muscle size best.• Novice weightlifters should start slowly.• See text for recommended guidelines for

developing an exercise prescription for weight gain.

Designing Programs to Improve Body Composition• You can decrease subcutaneous fat, fat weight, and percent

body fat of adults with aerobic and resistance exercise.• No type of aerobic exercise training is better than another

for fat loss.• Frequency of 4 days a week is found to be superior to 3 days

a week.• Combining aerobic and resistance training exercises

produces effective change in body composition of non-dieting individuals.

End of Presentation