Chapter 11 Special Topics in Adult Nutrition: Physical Activity & Weight Management Stella Lucia Volpe PhD,RD,LDN,FACSM

Reader Objectives After 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/m 2 is defined as overweight BMI if 30 kg/m 2 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