Nutrition Chpt. 6

Physical Activity Level (PAL)

1.2 Chair or bed bound 1.4-1.5 Sedentary 1.6-1.7 Very light 1.8-1.9 Moderate 2.0-2.4 Heavy activity

Total Energy Expenditure (TEE)

60-75% Resting Metabolic Rate 15-30% Physical activity 5-10% Thermic Effect of Food

Energy Output

Activities to sustain life require energy from food and body reserves Three demands for energy determine the body's total energy requirements (circulation, respiration, digestion, absorption) - Resting energy expenditure (REE) or Resting metabolic rate (RMR) - Physical activity level (PAL): more active, more calories - Thermic effect of food (TEF)

Calorie

Amount of energy in food or the amount that is expended in physical actions.

Thermic effect of food (TEF)

An increase in energy expenditure caused by the activities of circulation (transportation), respiration, digestion, absorption and storage of ingested food. 5-10% of the body's total energy needs for metabolism relate to the processing of food.

Energy Containing Nutrients

Carbohydrate is primary fuel Fat assists as storage fuel Protein is a back-up fuel source

Fuel Factors

Carbohydrate: 4 kcal/g Fat: 9 kcal/g Protein: 4 kcal/g Alcohol: 7 kcal/g

General Food Intake

Carbohydrates 45-65% Fats 30% (20% Unsaturated, 10% Saturated) Protein 20%

Energy requirements of involuntary body functions.

Chemical energy- in many metabolic products Electrical energy- in brain and nerve activities Mechanical energy- in muscle contraction Thermal energy- to maintain body temperature

Dietary Reference Intakes

Dietary guidelines for healthy Americans indicate energy needs based on 3 recommendations: 1) Maintain body weight in a healthy range. 2) To prevent gradual weight gain over time, make small decreases in food and beverage calories and increase physical activity. 3) Make recommended intakes with in energy needs - USDA Food Guides, DASH eating plan

Energy Systems

External energy cycle: plants transform radiation from the sun into stored chemical energy (carbohydrates, fats, proteins) Internal energy cycle: animals, including human beings use the stored chemical energy for body needs

Nutrient Density

High concentration of all nutrients, including vitamins and minerals in smaller amounts of a given food.

Caloric Density

High concentration of energy (kilocalorie) in a small amount of food. -foods high in fat have the highest caloric density

Involuntary work

Includes all activities of the body that are not consciously performed. Circulation (transportation), respiration, digestion, absorption.

Voluntary work

Includes all physical actions related to usual activities and additional physical exercise.

Measuring Resting Metabolic Rate

Indirect calorimetry- metabolic rate calculated on the basis of the rate of oxygen utilization. Thyroid function test- measures the activity of the thyroid gland and the blood levels of the hormone thyroxine.

Factors influencing BMR

Lean body mass Growth periods Body temperature Hormonal status

General formula for RMR

Men- 1 kcal x kg body weight x 24 hours Women- .9 kcal x kg body weight x 24 hours

Total Energy Requirements (TER)

Resting energy expenditure + Physical activity + Thermic effect of food To maintain daily energy balance: Calories in = calories out Intake > output = weight gain Intake < output = weight loss

Basal Metabolic Needs

Resting metabolic needs, at complete and total rest.

Resting Energy Expenditure (REE)

Sum of all internal working activities of the body at rest (circulation, respiration, digestion, absorption) Expressed in kcal/day Basal energy expenditure (BEE) is similar but requires complete rest, which is difficult to achieve.

Kilocalorie

The amount of heat that is necessary to raise 1kg of water 1 degree celcius. Used to designate the large calorie unit that is used in nutrition science. 1000 calories or 1 Calorie.

Density

The degree of concentration of material in a given substance.

Energy

The force or power to do work.

Metabolism

The sum of the body processes involved in converting food into various forms of energy.

Energy Intake

Three macronutrients are stored as: Glycogen- carbohydrates Adipose tissue- fat Muscle mass- protein The calculated energy value of actual food consumption. Calories in