Energy Balance, Weight, & Health - Chapter 9 Flashcards
Weight and Health
- Many different shapes and sizes
- Health problems with overweight and underweight
- Several problems with focusing just on weight
- Body composition most related to health
Energy Balance
- Balance occurs when energy in = energy out
- Part 1: Energy intake: foods, beverages
Defining Food Intake Regulation
- Hunger:
- Appetite:
- Satiation:
- Satiety:
Hunger
Physiological need to eat, sensation that demands relief
Appetite
Psychological desire to eat, learned motivation
Satiation
Perception of fullness that build throughout meal
Satiety
Perception of fullness that lingers after meal (inhibits eating until next meal)
Estimating Energy Needs
- Quick and easy estimation of energy needs:
- Males:
- Body weight in kg x 24 = kcal/day - Females:
- Body weight in kg x 22 = kcal/day
- Males:
Food Intake Regulation: Inside the Body
- Hormones:
- E.g. Leptin:
- Appetite suppressing
hormone produced in fat
cells
- Operates on feedback
mechanism
- E.g. Leptin:
What are some external cues that can lead to overeating?
- Wide variety of delectable foods
- Human sensations or emotions
- Time of day
- Stress
What food-related factors can lead to overeating?
- Pricing (cheap food options)
- Availability of food
- Advertising that promotes food consumption
How does physical inactivity relate to energy storage?
Lack of physical activity reduces energy expenditure, leading to excess energy being stored as fat.
Energy Balance
Part 2: Energy Expenditure
Energy Expenditure
- 50-65%: BMR (basal metabolic rate: all activities to sustain life)
- 25-50%: voluntary activity (not included in BMR)
- 5-10%: thermic effect of food (increased metabolism for ~5 hours after eating a meal) (not included in BMR)
Factors That Affect BMR
- Age
- Height
- Growth
- Body Composition
- Fever, stress
- Environmental temperature
- Fasting, Starvation, Malnutrition
- Thyroxin
What is anthropometry in assessing body composition?
It is the measurement of body size and proportions, such as waist circumference.
- Fat fold or skin fold using calipers
What are the healthy waist circumference values for males and females?
- Males: Less than 102 cm (40 inches)
- Females: Less than 88 cm (35 inches)
What is central obesity, and why is it significant?
- Central obesity (android or apple-shaped body) refers to fat accumulation in the upper body.
- It is associated with a higher risk of death from all causes compared to lower-body fat distribution.
What is the difference between android and gynecoid obesity?
- Android obesity:
- Upper body fat, “apple-shaped”; higher health risks.
- Gynecoid obesity:
- Lower body fat, “pear-shaped”; lower risk of health complications.
What does density refer to in assessing body composition?
Lean tissue is denser than fat.
What is underwater weighing used for in body composition assessment?
To determine body volume and density.
What principle does bioelectrical impedance analysis (BIA) rely on?
Lean tissue and water conduct electrical current, helping to estimate body composition.
Which method measures body composition using density?
Underwater weighing.
Which body composition method uses conductivity as its principle?
Bioelectrical impedance analysis (BIA).
What radiographic method is used to assess body composition?
Dual-energy X-ray absorptiometry (DEXA).
What does DEXA measure in assessing body composition?
Total body fatness, fat distribution, and bone density.
What does BMI stand for?
Body Mass Index
For which age group is BMI commonly used?
Adults over 20 years.
What is the formula for calculating BMI?
Weight in kilograms divided by height in meters squared BMI= weight (kg)/height (m)2
BMI & Weight Status Category
- < 18.5
- Underweight
- 18.5 - 24.9
- Healthy weight
- 25 - 29.9
- Overweight
- 30 - 34.9
- Obese class 1
- 35 - 39.9
- Obese class 2
- > 40
- Obese class 3
How does all-cause mortality relate to BMI?
It increases at very low and very high BMI levels.
What happens to mortality risk when moving from overweight to normal weight?
There is not much change in risk.
What happens to mortality risk when moving from obese to normal weight?
There is a significant decrease in risk.
Why is BMI commonly used to measure health?
Because it provides a quick and simple estimate of body weight relative to height.