Unit 13 Energy Balance, Langara College PDF

Energy Balance and Weight Management UNIT 13 NUTR 1100- Introduction to Nutrition Learning objectives At the end of this chapter, you should be able to: Describe energy balance and energy expenditure Discuss factors affecting food intake and body weight Describe health...

Energy Balance and Weight Management UNIT 13 NUTR 1100- Introduction to Nutrition Learning objectives At the end of this chapter, you should be able to: Describe energy balance and energy expenditure Discuss factors affecting food intake and body weight Describe health risks associated with obesity Distribution of Obesity Men Low income Ethnicity Immigration status (healthy immigrant effect)- Excess body fat increases disease risk high blood pressure menstrual irregularities heart disease breast, uterus, prostate, & colon high blood cholesterol cancer type-2 diabetes incidence and severity of gallbladder disease infectious disease arthritis poor wound healing sleep disorders surgical complications respiratory problems Healthy Body Weight Heathy weight: minimizes health risks and promotes overall health Body weight= weight of fat + lean body mass Lean body mass- mass of non-fat body (bone, muscle and internal organs) Body Mass Index Body Mass Index (BMI)- most common measure to assess body weight Measure of body weight relative to height BMI = Weight in kilograms/(Height in meters)2 or [Weight in pounds/(Height in inches)2] × 703 Body composition- relative proportions of fat and lean tissue Body Mass Index BMI & Health Is BMI a valid measure? It is not the number but what that BMI comprises (body composition) Cannot provide a full picture of overall health or individual’s risk for disease BMI limitations BMI can be used for initial screening but need to consider other factors when determining health risk of an individual: Body composition Fat % fitness Measuring body composition Body fat % - better measure of obesity than BMI Body fat Young adult female : healthy level body fat=21-32% of total weight Young, adult male :healthy level body fat= 8 to 19% of total body weight With age ? LBM ↓ Body fat ↑ Other measures Waist circumference: measure of central obesity (abdominal/visceral fat) >102 cm in men and 88cm in women is associated with ↑ risk of disease Measures are ethnic specific >92 cm in men and 80 cm in women Mediterranean, Middle eastern, African >90 cm and 80 cm in South Asian, Asian, Chinese, Japanese Body Fat location Visceral fat: Subcutaneous fat: ✤ adipose tissue around abdominal organs (apple shape) ✤ adipose tissue under the skin, for example, in hips ✤ more metabolically active and legs (pear shape) ✤ associated with higher ✤ no ↑ health risks disease risk Energy balance (over time) Weight maintenance: calories consumed = calories expended Weight gain: calories consumed > calories expended Weight loss: calories consumed < calories expended But not always as simple as this! Many factors can lead to weight gain Appetite vs. hunger Appetite: drive to consume specific foods triggered by external cues (for example, sight or smell) independent of hunger Hunger: drive to consume food that is triggered by internal physiological signals Genes & body weight 40-70% influence >100 genes are associated with body weight management 20–30 obesity genes produce proteins affecting how much food you eat, how much energy you expend, and the way fat is stored How does the body store excess calories? Small amount of energy is stored as glycogen in liver and skeletal muscle Remainder stored as fat in adipocytes Storing and retrieving calories Weight loss diets- Too good to be true Fast weight loss- >1kg/week Very low calorie (below 800kcal/day) Deprive foods or add supplements Expensive contracts Short term but not sustainable Doesn’t include exercise No magic pill? Weight cycling or yo-yo dieting Unhealthy ways to lose weight severely restricting energy intake