Chapter 11Special Topics in Adult Nutrition: Physical Activity & Weight Management

Stella Lucia Volpe PhD,RD,LDN,FACSM

Reader ObjectivesAfter completing this chapter and reflecting on the

contents, you should be able to:

1. Describe the differences between overweight and obese and implications for risk of disease;

2. Explain the components of energy balance and how they can impact weight management;

3. Describe the role of physical activity in maintaining a healthy body weight in adults, based upon scientific evidence.

Definitions of Obesity and Overweight

• Ranges of body weight that are above what is regarded as healthy for a given height

• Ranges of body weight that increase the risk of chronic disease

• BMI between 25 to 29.9 kg/m2 is defined as

overweight• BMI if 30 kg/m2 is defined as obese• Problems with BMI--percent body fat, lean

body mass

Total Energy Expenditure• Total energy expenditure: basal energy

expenditure, the thermic effect of food, the thermic effect of activity andd non-exercise activity thermogenesis.

• BEE and BMR are measured in kilocalories per day

• Thermic effect of food: the amount of energy required for absorption and digestion of food

Total Energy Expenditure, cont.

• Thermic effect of exercise: most variable--from 10% (sedentary) to 100% (Olympic athletes)

• Non-exercise activity thermogenesis (NEAT): the energy of “working, playing, and dancing”--can account for up to 2000 kcal/day

• Why there are lower levels in obese individuals

Physical Activity and Obesity Prevention

• Definition of physical activity• Includes occupational, household, leisure-

time and transportation• Definition of exercise• Five components of exercise:

cardiorespiratory endurance, muscular endurance,muscular strength, flexibility, and body composition.

Weight Loss Goals

• Individuals overestimate their energy expenditure by 500 kcals, and underestimate their energy intake by 1000 kcal.

• Obese individuals have unrealistic weight loss goals

• Unrealistic expectations of weight loss expectations lead to high rates of recidivism following weight loss trials.

How much exercise?

• CDC 1995: at least 30 min. of exercise/day for cardiovascular fitness.

• This is not enough for weight loss.

• DRI 2005: exercise at least 30 min./day at high intensity or at least 60 min./day at low intensity

• Combination of reductions in energy intake and increases in energy expenditure should be a component of weight loss intervention programs (Jakicic et. al,2001)

Physical activity interventions and weight loss

Research findings:• Exercise in multiple bouts could be a way of

encouraging more physical activity in individuals

• Access to home exercise equipment may assist in exercise adherence, resulting in weight loss in the long-term

• The greater energy expenditure, the more body weight lost.

Physical activity and weight loss in the primary care setting

• Pilot studies suggest that the primary care setting may be one of the best places for prevention of weight gain and for weight loss.

• Question: “Are health care professionals advising patients with diabetes or at risk for developing diabetes to exercise more?”

Successful Maintenance of weight loss

• The most difficult phase of any weight loss program

• Small changes can lead to big effects on the prevention of weight gain.

• Successful interventions increase energy expenditure and decrease energy intake; must take into account behavioral and environmental factors.

Successful Maintenance of Weight Loss (continued)

• Interventions that include the entire family (examples are walking and increasing cereal consumption).

• National Weight Control Registry: consumption of a low-energy diet, moderate fat intake, limited consumption of fast food, and high amounts of physical activity/exercise