Energy Balance Chapter 7

Energy Intake Calories come from carbohydrates, protein, fat, and alcohol The total number of calories in a food or diet can be estimated by multiplying total grams of carbohydrates, protein, or fat by the appropriate number of calories/gram Even when all food consumed is measured, the nutrient values available in food composition references represent average, not actual, nutrition content

Energy Intake (cont’d) Easier way to count calorie intake is to estimate the number of servings from each food group a person consumes; multiply the number of servings by the average amount of calories in a serving; then add the calories from each group to get an approximation of the total calories consumed Accuracy of “counting servings” depends on the quality of foods consumed and the accuracy of portion size estimation

Energy Expenditure Basal metabolism Caloric cost of staying alive or the amount of calories required to fuel the involuntary activities of the body at rest after a 12-hour fast Basal metabolic rate (BMR) accounts for approximately 60% of total calories expended The less active a person is, the greater the proportion of calories used for basal energy expenditure (BEE)

Energy Expenditure (cont’d) Basal metabolism (cont’d) Rule-of-thumb guideline for estimating BMR is to multiply healthy weight (in pounds) by 10 for women and 11 for men When actual weight exceeds healthy weight, an “adjusted” weight of halfway between healthy and actual can be used Rule of thumb based on weight only

Energy Expenditure (cont’d) Basal metabolism (cont’d) Lean tissue (muscle mass) contributes to a higher metabolic rate than fat tissue Loss of lean tissue that usually occurs with aging beginning sometime around age 30 is one reason why calorie requirements decrease as people get older

Energy Expenditure (cont’d) Physical activity Accounts for approximately 30% of total calories used Rule-of-thumb method for estimating daily calories expended on physical activity is to calculate the percent increase above BMR based on the estimated intensity of usual daily activities

Energy Expenditure (cont’d) Estimating total calorie requirements Estimated energy requirements (or EER) based on age, weight, height, and physical activity (PA), with defined PA factors for men and women based on intensity of activity Quicker and easier reference is the MyPyramid calorie level table based on gender, age, and activity

Calories in Versus Calories Out State of energy balance is the relationship between the amount of calories consumed and the amount of calories expended A “positive” energy balance occurs when calorie intake exceeds calorie output A “negative” calorie balance occurs when calorie output exceeds intake

Question Is the following statement true or false? A man with an actual weight of 210 pounds and a “healthy” weight of 175 pounds has a basal metabolic rate of 2,220.

Answer False. Rationale: When actual weight exceeds healthy weight, an “adjusted” weight of halfway between healthy and actual can be used: 210 – 175 = 35 35/2 = 17.5 175 + 17.5 = 192.5 192.5 x 11 = 2117.5 BMR

What Is “Normal” Weight “Normal” or “desirable” weight is that which is statistically correlated to good health 3 criteria used for assessing overweight and obesity: Body mass index (BMI) Waist circumference Existing health problems

What Is “Normal” Weight (cont’d) Body mass index Body mass index (BMI) has replaced traditional weight–height calculations that were used to determine “ideal” or “desirable” body weight Formula to calculate BMI is weight in kg/height in meters squared or weight in pounds/height in inches squared x 703 Drawback Does not take body composition into account Skinfold measurements and bioelectrical impedance can assess body composition, but neither technique is widely used

What Is “Normal” Weight (cont’d) Waist circumference Location of excess body fat may be a more important and reliable indicator of disease risk Storing a disproportionate amount of total body fat in the abdomen increases risks for type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease Abdominal fat is clinically defined as a waist circumference ≥40 inches in men and ≥35 inches in women

What Is “Normal” Weight (cont’d) Existing health problems Presence of existing health problems impacts a person’s absolute risk related to weight Generally, the number and severity of comorbid conditions increases with increasing levels of obesity

Energy Balance in Health Promotion Approximately 66% of the adult American population is overweight or obese Preventing or reducing overweight is achieved by adopting a lifestyle approach that includes healthier food choices, increasing physical activity, and behavior modification

Energy Balance in Health Promotion (cont’d) Healthier choices Encompasses a 2-pronged approach Eating less of certain items Eating more of others Emphasis is on healthy and wholesome choices Remember fat-free foods still contain calories from protein and carbohydrates Reducing alcohol intake is another way to consume fewer calories

Energy Balance in Health Promotion (cont’d) Portion control Portion sizes have grown over the last 20 years “Portion distortion” appears to be a widespread problem Change the environment Food should be less accessible, less visible, and proportioned in smaller quantities

Energy Balance in Health Promotion (cont’d) Physical activity Only 30% of American adults engage in regular leisure-time physical activity; 39% of adults do not engage in any leisure-time physical activity Benefits of increasing activity are dose-dependent and occur along a continuum Minimum of 30 minutes/day of moderate-intensity activity above usual activity is recommended Other types of exercise are also recommended

Question There are 3 criteria used for assessing overweight and obesity. What is one of these criteria? a. Height b. Healthy weight c. Existing health problems d. Basal metabolic rate

Answer Existing health problems Rationale: 3 criteria used for assessing overweight and obesity include: Body mass index (BMI) Waist circumference

How to Burn 150 Calories (Based on a 150-Pound Person) Pedal a stationary bicycle for 20 minutes Practice fast dance steps for 24 minutes Work in the garden for 27 minutes Walk briskly (3.5 mph) for 33 minutes Clean the house for 38 minutes

Suggestions for Increasing Activity Find something enjoyable Use the buddy system Spread activity over the entire day if desired Start slowly and gradually increase activity Move more Keep an activity log