Energy Balance and Obesity Jamie Pope, Steven Nizielski, and Alison McCook NUTRITION for a Changing World FIRST EDITION Chapter 15 Energy Balance and Obesity The Sitting Disease © 2016 by W. H. Freeman and Company & Scientific American

Chapter 15 Objectives List the health consequences associated with obesity, and describe how excess body fat increases the risk of developing these conditions Describe the concept of energy balance Identify and describe the components of total energy expenditure Describe factors that affect basal metabolic rate Describe activities that are examples of nonexercise activity thermogenesis (NEAT) Describe factors that contribute to the development of obesity Use body mass index and waist circumference to evaluate someone’s risk of chronic disease Describe methods for determining body composition Discuss strategies for successful weight loss and maintenance

The Sitting Disease Obesity epidemic Obesity Overweight Complex disease influenced by multiple factors Genetics Environment Behavior Obesity Over one-third of U.S. adults in 2014 Overweight Over two-thirds of U.S. adults in 2014 “Genetics loads the gun and environment pulls the trigger.” Genetics determine a person’s susceptibility to obesity but the environmental changes promote low levels of physical activity and the consumption of energy-dense diets promote weight gain in genetically susceptible individuals.

The Sitting Disease “Genetics loads the gun and environment pulls the trigger.” Genetics determine a person’s susceptibility to obesity but the environmental changes promote low levels of physical activity and the consumption of energy-dense diets promote weight gain in genetically susceptible individuals.

Energy In, Energy Out Energy Calorie Energy in Energy out Capacity to do work Calorie Energy required to raise 1 g of water 1°C Kcal is the energy required to raise 1 kg of water 1°C Energy in Energy we consume Energy out Energy we burn

Energy Balance

Excess Body Fat Enlarged fat cells produce excess hormones and hormone-like messengers Hormones cause low-grade inflammation Adipose tissue (body fat) secretes hormones, which leads to low-grade chronic inflammation and increased risk of chronic disease.

Biology of Hunger Short-term system Long-term system Mediated by hormones Ghrelin Mediated by stomach pressure Regulates hunger and satiety Long-term system Leptin Adjusts food intake and energy expenditure Maintains adequate fat stores

Hormones in Energy Balance Ghrelin Produced in the stomach Stimulates hunger Leptin Produced by adipose tissue Suppresses hunger

Factors Affecting Fullness Satiation Sense of fullness Leads to termination of a meal Satiety Feeling the effect of a meal Lacking interest in food Gastric distention Gut peptides

Hunger and Appetite Hunger Appetite Is a biological impulse Liking or wanting of food Is a product of sensory stimuli and perceived pleasure Affected by the “toxic food environment”

Energy Expenditure Total energy expenditure (TEE) Basal metabolism Thermic effect of food (TEF) Activity energy expenditure (AEE)

Basal Metabolic Rate (BMR) Factors that affect BMR Fat-free mass (FFM) Age Sex Growth Hormones Starvation Illness Pregnancy and lactation Ethnicity Caffeine Smoking Sleep Fat-free mass is the total body mass minus fat mass (adipose tissue). Fat-free mass is the greatest factor impacting BMR. The higher a person’s FFM, the greater their BMR.

Fat-free mass is the total body mass minus fat mass (adipose tissue) Fat-free mass is the total body mass minus fat mass (adipose tissue). Fat-free mass is the greatest factor impacting BMR. The higher a person’s FFM, the greater their BMR.

Activity Energy Expenditure Exercise Nonexercise activity thermogenesis (NEAT) Activities of daily living Levine found that obese people sit more then lean people; they had less NEAT.

Lifestyle and Energy Balance

Lifestyle and Energy Balance

Lifestyle and Energy Balance

Lifestyle and Energy Balance

Lifestyle and Energy Balance

Lifestyle and Energy Balance

What Is a Healthy Body Weight? Body mass index (BMI) body weight (kg)/height2 (m2)

Body Mass Index

Waist Circumference Estimator of abdominal obesity Waist circumference exceeds 35 inches in women Waist circumference exceeds 40 inches in men Visceral fat is an independent health risk Cardiovascular disease Type 2 diabetes Premature all-cause mortality

Waist Circumference

Analyzing Body Composition Dual-Energy X-Ray Absorptiometry (DEXA) Underwater Weighing (Hydrodensitometry) Bioelectrical Impedance Skinfold Thickness Air Displacement

Weight-Loss Recommendations Weight-loss recommended for anyone with a BMI of 30 or greater and anyone overweight with two or more other risk factors Elevated waist circumference Cardiovascular disease Family history of cardiovascular disease Smoking Hypertension Diabetes Physical inactivity Age (men 45 years or older; women 55 years or older or postmenopausal)

Weight Loss Modest reduction of body weight results in health improvements Losing and maintaining 5% to 10% of body weight can reduce risk of chronic disease and all-cause mortality by about 50%

Surgical Approaches to Weight Loss For BMI of 40 or above or BMI of 35 or above with additional risk factors Benefit should be greater than significant risk

Dietary and Lifestyle Approaches to Weight Loss Effective approaches Increase physical activity Reduce calorie intake with nutrient-dense foods Eat moderately low-fat diet (less than 30% of calories) Eat moderately high-protein diet (25% to 30% of calories) Include plenty of non-starchy vegetables, fruit, whole grains with high fiber, and lean sources of protein

Determine Your Estimated Energy Requirement Estimate your physical activity level (PA). Convert your body weight in pounds to kilograms by dividing by 2.2. Convert your height in inches to meters by multiplying by 2.54 (to convert to centimeters) and then dividing by 100 to convert to meters. Enter your values into the appropriate equation below for people 19 years and older: Men: EER = (662 − (9.53 x age) + PA x (15.91 x weight in kg) + (539.6 x height in m) Women: EER = (354 − (6.91 x age) + PA x (9.36 x weight in kg) + (726 x height in m)

Weight-Loss Maintenance National Weight Control Registry (NWCR) Common strategies of successful weight-loss maintenance Maintaining a lower-fat, reduced-calorie eating plan Eating breakfast Weighing self at least once a week Watching fewer than 10 hours of television per week Exercising on average about one hour per day

A Moratorium on the Chair Increase NEAT “Get out of the chair” Move more

Summary Obesity is at epidemic proportions in the United State, with more than two-thirds of adults classified as overweight or obese Energy, the capacity to do work, is required to perform all functions necessary to sustain life and is obtained through the breakdown of carbohydrates, fats, proteins, and alcohol in food A calorie, a unit of measure, is defined as the energy required to raise 1 gram of water 1°C. The energy in food is commonly measured in units of kilocalories (1,000 calories). A kilocalorie (kcal) is the energy required to raise 1 kilogram of water 1°C. Energy balance is a reflection of energy intake versus expenditure. Although there are many factors that contribute to the development of obesity, fundamentally it results from chronic positive energy balance. Negative energy balance is necessary for weight loss Obesity increases the risk of multiple chronic diseases and premature death. Hormonal changes associated with excess body fat cause a low-grade chronic inflammation throughout the body that has adverse health effects

Summary (Cont’d) Energy balance and food intake are regulated through a short-term system and a long-term system. The short-term system is mediated by hormones and stomach pressure and is responsible for triggering hunger and satiety during individual meals. The long-term system, mediated by a different set of hormones, adjusts food intake and energy expenditure to maintain adequate fat stores Satiation is the sense of fullness we feel while eating and leads to the termination of a meal. Satiety is the effect that the meal has on our interest in food and hunger levels after and between meals The hormone ghrelin stimulates hunger by activating specific neurons in the brain. Circulating levels of ghrelin in the blood increase just before meals and decrease after eating

Summary (Cont’d) The hormone leptin is produced primarily by adipose (fat) tissue and has a role in long-term energy balance. Its circulating concentration is closely associated with total body fat Hunger is the biological impulse that drives us to seek out food and consume it to meet our energy needs. Appetite is a desire for or liking of food for reasons other than, or in addition to, hunger Total energy expenditure (TEE) is composed of basal metabolism, the thermic effect of food, and activity energy expenditure (AEE)

Summary (Cont’d) Basal metabolism is the energy expenditure required to maintain the essential functions that sustain life. It accounts for about 60% of TEE in a typical sedentary individual, with most variation from person to person accounted for by differences in fat-free mass Thermic effect of food (TEF) is the energy needed to digest, absorb, and metabolize nutrients in our food. TEF is generally equivalent to 10% of the energy content of the food ingested and does not vary greatly between people Activity energy expenditure is the amount of energy individuals expend in physical activity per day and is the most variable component of TEE Body mass index (BMI) is an indirect measure of body fat, calculated from a person’s weight and height. “Underweight,” “normal,” “overweight,” and “obese” are labels for ranges of body weight on the BMI scale

Summary (Cont’d) The greater the BMI, the higher the risk of premature mortality and the risk of obesity-associated diseases. A BMI in the underweight range is also associated with increased premature mortality Waist circumference indicates body fat distribution and the presence of excess visceral fat, which has been shown to be an independent health risk Body composition can be measured in a variety of ways, including skinfold thickness with calipers, underwater weighing, air displacement, bioelectrical impedance, and dual-energy x-ray absorptiometry

Summary (Cont’d) Weight loss, including dietary modifications and increased physical activity, is recommended for anyone with a BMI of 30 or higher or those who are overweight and have two or more risk factors, or have an elevated waist circumference. For those with extreme obesity (a BMI of at least 40 or a BMI of at least 35 with additional risk factors), weight-loss (bariatric) surgery may be recommended Modest weight loss and maintenance (5% to 10% of body weight) can improve health, as well as reduce the risk of chronic diseases and premature death Healthy weight-loss plans maximize nutrient density while reducing calorie intake; increase physical activity; incorporate behavioral strategies to enhance compliance; address individual health concerns; and consider maintenance of a lower body weight