Body Composition and Measurement
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Questions and Answers

What percentage of body fat is present in a newborn?

  • 10%
  • 14% (correct)
  • 19%
  • 28%

    • What is the purpose of bioelectrical impedance devices in measuring body composition?

  • To calculate total body potassium
  • To determine body fat percentage using electrical signals (correct)
  • To measure body density
  • To measure body water

    • Which of the following is NOT a method of measuring body composition?

  • Dual-Energy X-ray Absorptiometry (DXA) (correct)
  • Methyl histidine or creatinine excretion
  • Mid-arm circumference
  • Skinfold measurements

    • What is the approximate weight of a 10-year-old male with 13% body fat?

    <p>31 kg</p> Signup and view all the answers

    What is the percentage of body fat in an obese male adult?

    <p>28%</p> Signup and view all the answers

    Which of the following skinfold measurements is NOT typically used to measure body composition?

    <p>Calf</p> Signup and view all the answers

    What is the primary function of leptin in regulating hunger and satiety?

    <p>To signal the state of the fat stores</p> Signup and view all the answers

    Which of the following neuropeptides is involved in stimulating hunger pathways?

    <p>NPY</p> Signup and view all the answers

    What is the primary role of insulin in regulating hunger and satiety?

    <p>To signal the fullness of carbohydrate stores</p> Signup and view all the answers

    Which of the following brain regions is responsible for integrating hunger and satiety signals?

    <p>Hypothalamus</p> Signup and view all the answers

    What is the primary function of POMC-related peptides in regulating hunger and satiety?

    <p>To suppress appetite through the release of PYY 3-36</p> Signup and view all the answers

    Which of the following short-term signals is involved in bringing about the feeling of satiety?

    <p>Signals from the GI tract</p> Signup and view all the answers

    What is the primary function of ghrelin in regulating hunger and satiety?

    <p>To stimulate hunger pathways</p> Signup and view all the answers

    What determines the last spoonful of food?

    <p>Short-term signals from the GI tract</p> Signup and view all the answers

    What is the purpose of measuring the volume of the chamber with and without the subject in the Bod Pod?

    <p>To determine the body density and fat-free mass of the subject</p> Signup and view all the answers

    What is the energy density of protein in kilojoules per gram?

    <p>22.7 kj/g</p> Signup and view all the answers

    What is the approximate energy equivalent of 1 liter of oxygen consumed?

    <p>20 kjoules</p> Signup and view all the answers

    What is the energy requirement for an infant in the first year, relative to an adult?

    <p>Twice the adult requirement</p> Signup and view all the answers

    What is the approximate daily energy expenditure for a person who is lactating?

    <p>5000 kj/day</p> Signup and view all the answers

    What is the percentage of energy expenditure that is lost as heat?

    <p>50%</p> Signup and view all the answers

    What is the typical 24-hour energy expenditure for an adult?

    <p>10000 kj</p> Signup and view all the answers

    What is the region of the brain that plays a crucial role in regulating energy intake?

    <p>Hypothalamus</p> Signup and view all the answers

    What is the basal metabolic rate in MJ/day for moderately obese individuals?

    <p>7.6</p> Signup and view all the answers

    Which of the following is a socio-economic factor contributing to obesity?

    <p>Lower socio-economic class in the UK</p> Signup and view all the answers

    What is the percentage of energy reduction in children's physical activity compared to 25 years ago?

    <p>65%</p> Signup and view all the answers

    What is the result of faecal transplants from obese to lean individuals?

    <p>Weight gain</p> Signup and view all the answers

    What is the function of butyrate produced by gut microbes?

    <p>Colonic cell proliferation and maintenance of healthy gut barrier</p> Signup and view all the answers

    What is the effect of having one FTO gene on body weight?

    <p>1.5 kg heavier</p> Signup and view all the answers

    What is the characteristic of people with 'high-risk' FTO genotypes?

    <p>Impaired satiety and increased food intake</p> Signup and view all the answers

    What is the function of propionate produced by gut microbes?

    <p>Stimulating PYY production and decreasing appetite</p> Signup and view all the answers

    According to the Finnish study in 1991, which of the following is a risk factor for obesity?

    <p>Giving up smoking</p> Signup and view all the answers

    What is the relative risk of myocardial infarction (MI) associated with obesity?

    <p>1.9</p> Signup and view all the answers

    Which of the following conditions is NOT associated with obesity?

    <p>Cancer of the pancreas</p> Signup and view all the answers

    What is the primary reason high protein diets are often easier to follow?

    <p>The satiety value of protein is higher than carbohydrate or fat</p> Signup and view all the answers

    What is the primary concern with most keto diets?

    <p>High saturated fat content</p> Signup and view all the answers

    What is the primary benefit of intermittent fasting according to the content?

    <p>No specific benefit is mentioned in the content</p> Signup and view all the answers

    What is the primary reason why protein should be very limited in a keto diet?

    <p>To allow the liver to produce ketones</p> Signup and view all the answers

    What is the outcome of keto diets after one year, compared to other energy-restricted diets?

    <p>No more successful than other energy-restricted diets</p> Signup and view all the answers

    Study Notes

    Body Composition

    • Body composition is measured as Body = Fat + Fat-Free Mass
    • Newborns have 14% body fat, increasing to 13% for 10-year-old males and 19% for 10-year-old females
    • Adult males have 15% body fat, while adult females have 28% body fat
    • Obese males have 28% body fat

    Measurement of Body Composition

    • Methods of measurement include:
      • Body density
      • Body water
      • Total body potassium (K)
      • Methyl histidine or creatinine excretion
      • Skinfold measurements (biceps, triceps, supra iliac, sub scapular)
      • Mid-arm circumference
      • Bioelectrical impedance (uses electrical signal to measure body fat percentage)
      • The Bod Pod (air displacement plethysmography)

    Energy Derived from Food

    • Energy is derived from food in the following amounts:
      • Carbohydrate: 4 kcal/g, 16.8 kj/g
      • Fat: 9.2 kcal/g, 38.6 kj/g
      • Protein: 5.4 kcal/g, 22.7 kj/g
      • Alcohol: 7 kcal/g, 29.4 kj/g

    Energy Requirements

    • Energy requirements depend on:
      • Basal metabolic rate (kj/hour/kg body weight)
      • Diet-induced thermogenesis
      • Physical activity (e.g., sitting = 1.7BMR, football = 7BMR)
      • Environmental temperature
      • Growth, pregnancy, lactation (e.g., 0.8 MJ or 200 kcal/day in trimester 3, 2 MJ or 500 kcal/day in lactation)
      • Age (decrease in BMR and activity)

    Energy Balance

    • Energy balance is achieved when energy intake equals energy expenditure, resulting in no change in body mass
    • Energy balance is regulated by the hypothalamus, which receives signals from the body (e.g., leptin, insulin)

    Regulation of Energy Intake

    • Long-term signals:
      • Leptin and insulin (signal the state of fat stores and carbohydrate stores, respectively)
      • Act in the hypothalamus to regulate hunger and satiety pathways
    • Short-term signals:
      • From the GI tract, hepatic portal vein, and liver
      • Bring about the feeling of satiety through the vagus and circulation

    Causes of Obesity

    • Socio-economic, cultural (e.g., obesity in lower socio-economic class in the UK and Western world)
    • Endocrinological (e.g., adrenal hyperactivity, hypothyroidism)
    • Physical activity (e.g., children spend 65% less energy than 25 years ago)
    • Microbiota (e.g., evidence that GI tract of lean subjects has more diverse microbiota than obese)
    • Genetic factors (e.g., FTO gene, 2 oxoglutarate dependent dioxygenase)

    Conditions Associated with Obesity

    • Cardiovascular disease
    • Diabetes mellitus type 2
    • Hypertension
    • Respiratory problems
    • Gall bladder stones
    • Osteoarthritis in weight-bearing joints
    • Reduced fertility in men
    • Polycystic ovary syndrome
    • Breast, endometrial, colon, and prostate cancers

    Therapy: Diets

    • All diets work if energy intake is restricted, but adherence is key
    • Fad diets are often metabolically undesirable and may not lead to long-term weight loss
    • High-protein diets may be easier to follow due to satiety value of protein
    • Keto diet (primarily used for epilepsy, may have concerns about high saturated fat content)
    • Intermittent fasting (claims to improve thinking, heart health, and type 2 diabetes, but most studies are on animals and human studies show no benefit compared to continuous calorie restriction)

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    Related Documents

    Energy Balance and Control of Body Weight (NAM 2023) PDF

    Description

    This quiz assesses knowledge on body composition, including measurement methods and percentage of body fat in different populations. Test your understanding of bioelectrical impedance, skinfold measurements, and more.

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