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Learn about energy intake, expenditure, basal metabolism, and maintaining a healthy weight. Discover how to estimate calorie intake, BMR, and total calorie requirements for optimal health. Explore the balance between calories consumed and expended for a healthy lifestyle.
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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 • Existing health problems
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