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