1. Chapter Eight - Part One
Weight Control
Food & Nutritional Health NUT SCI –242
Karen Lacey, MS, RD, CD © Spring 2005

2. Terms
Overweight: 10% - 20% above the desirable weight for height, or a BMI of
Underweight: 10% or more below the desirable weight for height, or a BMI of less than 18.5
Obesity: 20% or more above the desirable weight for height, or a BMI of 30 or greater

4. Problems Associated with Underweight
Due to decreased body fat stores, may be disadvantaged when energy reserves may be needed, such as during physiological stress, injury or famine
Other problems include:
Menstrual irregularity
Infertility
Osteoporosis

6. Problems Associated with Overweight
High blood pressure
High cholesterol
Diabetes
Heart disease
Gallbladder disease

8. I. What is a Healthful Weight?
Body Weight vs. Body Fat
Body weight and body fat are not the same thing
Body composition is important

10. B. Measuring Body Fat Difficult to measure Methods include:
Underwater weighing: the entire body is submerged into a tank of water and water displacement is measured to determine body density and body fat percentage

12. Cont’d
Biochemical Impedence: estimate body fat content by measuring how quickly electrical current is conducted through the body
Fat increases resistance against electrical current

14. Cont’d
Skinfold Test: thicknesses of folds of skin various places on the body are measured with an instrument called a caliper
Simple & inexpensive

16. C. Distribution of Fat Central obesity: excess fat on the abdomen and
around the trunk
Central obesity represents a greater risk to health than fat elsewhere on the body

18. D. Weighing in for Health
Health risk is dependent upon three factors:
Body weight
Amount & location of body fat
Current health status
Waist circumference: a measure used to assess a person’s abdominal fat

19. Cont’d
Body Mass Index (BMI): an index of a person’s weight in relation to height which correlates with total body fat content

22. II. Energy Balance Fat stores= energy in – energy out Energy in:
Calorie content of food taken in
3,500 calories = 1 pound of body fat
Energy out:
Basal metabolism: the energy required to fuel the activities of the cells necessary to sustain life

23. Cont’d Fuel for voluntary activities
Number of calories an activity uses is determined by:
Muscle mass required
Weight of body part being moved
Duration of activity

25. III. Causes of Obesity Genetic vs. Environment
Set-pt. Theory: the theory that the body tends to maintain a certain weight by adjusting hunger, appetite and food energy intake compared to metabolism so that a person’s effort to alter weight may be unsuccessful
Fat-cell Theory

27. Cont’d Heredity may contribute to obesity
Factors in surroundings encourage eating
Availability, variety, appearance, lighting, music, location, companions
External cue theory: the theory that some people eat in response to such external factors as the presence of food or the time of day rather than to such internal factors as hunger

29. B. Environment & Behavior
Hunger
A physiological sensation
A negative experience people eat to avoid
Appetite
A physiological experience
A positive experience- people eat for enjoyment

30. Cont’d Satiety The condition of being full or satisfied
A signal to stop eating
Other regulators:
Human sensations
Emotions
Situations
Arousal (ie, stress eating)
Underactivity