Chapter 8 – Energy Balance and Body Composition



Chapter 8 – Energy Balance and Body Composition

ENERGY BALANCE

1. BASAL METABOLIC RATE

• calories burned at rest for all body processes

• equals about % of the energy used daily

2. THERMIC EFFECT OF FOOD

• equals about 10-15% of energy needs

• calories needed to digest, absorb, and transport nutrients

Carbohydrate: 5-10%

Fat: 0-5%

Protein: 20-30%

Alcohol 20%

3. ENERGY FOR ACTIVITIES

• makes up about 15-20% of energy needs

• the number of calories burned during exercise depends on muscle mass, body weight, and activity

FACTORS THAT INFLUENCE THE BMR

• Age

• Height

• Growth

• Body Composition

• Fever and disease

• Extreme Temperature

• Fasting / Starvation

• Malnutrition

• Hormones

• Smoking

• Caffeine

• Sleep

• Sex

To Estimate Basal Metabolism (BMR):

• Women – 0.9 kcal / kg / hr OR 23 kcal/kg/day

• Men – 1.0 kcal / kg / hr OR 24 kcal/kg/day

1 kg = 2.2 pounds

To estimate TOTAL calorie needs, divide the BMR by .7 (for 70%)

BODY WEIGHT AND BODY COMPOSITION

HEALTHY WEIGHT:

• A weight within the suggested ranges for height

• A fat distribution pattern associated with a low risk of illness or death

• Freedom from medical conditions that would suggest a need for weight loss

OVERWEIGHT:

• ________% above standard weight for height

OBESE:

• more than ______% over standard weight for height

UNDERWEIGHT:

• more than ______% under standard weight for height

BODY MASS INDEX (BMI)

• An index of a person's weight in relation to height

• A measure of the risk of disease

• Does not account for body composition, sex, or frame size

|BMI |CLASSIFICATION |RISK OF DISEASE |

|under 18.5 |underweight |high risk |

|18.5 to 25 |normal |very low risk |

|25-30 |overweight |increased risk |

|30-35 |class I obesity |high risk |

|35-40 |class II obesity |very high risk |

|above 40 |class III obesity |extreme risk |

CENTRAL OBESITY

• carrying fat in the central abdominal area of the body (apple shape)

• can increase LDL-cholesterol and the risk for heart disease

• most common in men

• smokers and drinkers are very likely to have central obesity

• waist circumference above 35 inches for women and above 40 inches for men is associated with a higher risk of health problems

MEASURING % BODY FAT

• fatfold measurements (using skin calipers)

• bioelectrical impedence – uses a low-intensity electrical current

• air displacement plethysmography - measures the amount of air displaced by the person’s body

• dual energy x-ray absorptiometry (DEXA) – differentiates among lean body mass, fat tissue, and bone tissue

• underwater weighing (hydrodensitometry)

BODY FAT PERCENTAGES

• body fat tends to increase with age

• a high percentage of body fat increases the risk of disease

• percentage of body fat does not always directly correspond with weight for height charts

• women have (and need) a higher percentage of body fat than men

• women need enough body fat for normal hormone functioning and reproduction

• Body fat above 22% in young men, 25% in older men (over age 40), 32% in young women, and 35% in older women is defined as obesity and can lead to health problems

|PERSON |“IDEAL” BODY FAT RANGE |

|Women |20% - 31% |

| Athletic Women |15% - 20% |

|Men |11% - 21% |

| Athletic Men |5% - 10% |

PROBLEMS ASSOCIATED WITH LOW % OF BODY FAT or UNDERWEIGHT::

• infertility (especially with women)

• negative pregnancy outcome

• depression

• inability to keep warm

• abnormal hunger regulation

• osteoporosis

• harder to fight wasting diseases such as AIDS and cancer

• harder to handle surgery

CAUSES OF BEING UNDERWEIGHT

• Wasting diseases (cancer, infections, fever)

• Malabsorption (diarrhea, GI disease, laxative abuse)

• Hormonal imbalance (hyperthyroidism)

• Energy imbalance (too much exercise)

• Poor food intake / poor living situation

PROBLEMS ASSOCIATED WITH OBESITY OR HIGH % BODY FAT:

• Type 2 Diabetes

• Hypertension

• High blood lipids

• Cardiovascular disease

• Sleep Apnea

• Osteoarthritis

• Some Cancers

• Varicose Veins

• Gallbladder disease

• Respiratory problems

• Liver disorders

• Complications during pregnancy

• Low self-esteem

• Social and financial problems

• People with lifelong obesity are more than twice as likely to die prematurely as a person of normal weight

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Women: At 5'0 tall, start at 100 pounds. Add an additional 5 pounds for each inch over 5 feet.

Men: At 5'0 tall, start at 106 pounds. Add an additional 6 pounds for each inch over 5 feet.

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