L3 energy balance

Usable power

Derived from stored chemical energy in foods we eat

Allows people to:

power bodies

produce heat

Energy balance:

• relationship between energy intake and energy used by the body

• Energy expenditure:

• energy used by the body

Measurement of chemical form of energy in foods

Amount of energy needed to raise temperature of 1,000 g of water by 1º C

Mistakenly called calories

Bomb calorimeter measures kilocalories

Kilojoule: Amount of energy needed to move 1 kg with an acceleration of 1 meter per second

Metabolism of carbohydrate, protein, fat, and alcohol

End products of carbohydrate, protein, and fat metabolism:

carbon dioxide

water

energy in the form of ATP

End products of alcohol metabolism:

some of the same by-products

long-chain fatty acids

Simple calculations based on basic knowledge

Scientific databases contain analyses based on:

laboratory studies

manufacturer information

Availability and use of software programs based on these databases

Comprised of several components

Unique for each person

Measured indirectly or calculated using equations

Total energy expenditure:

processes in the body

physical activity

Energy required for vital functions in body at rest

Basal energy expenditure:

expression of basal metabolism as kcalories over 24 hours

different from resting energy expenditure

heavier individuals have higher resting metabolic needs

gender differences due to muscle mass and organ size

debates on relationship to age

Energy expended for body temperature regulation

varies based on surface area to weight ratio

thermoregulation challenges alter energy use

adjust energy expenditure calculations when thermoregulation issues occur

impact of extreme ambient temperatures

with normal conditions, little change

Increased needs with infancy, childhood, adolescence, pregnancy, and lactation

A person’s metabolic rate is dependent on many things, including physical activity and the amount of muscle.”

The metabolic rate is influenced by the activity level, the amount of muscle mass, and body temperature, among other things. Muscle and organ tissue is more metabolically active than fat, so if the person who is overweight has more fat mass, the basal metabolic rate may be slower than someone of the same weight who has more muscle mass.

However, people will not become overweight if they have high metabolic rate. Increasing physical activity will help develop more muscle mass, which is more metabolically active.No two individuals will have exactly the same metabolic rate.

Metabolic cost of digestion, metabolism, and storage of nutrients

Typically 10% of every value of the food

Protein thermic effect: 20 to 30%

Alcohol thermic effect: up to 13%

Fat thermic effect: less than 5%

Thermogenesis

Physical component of energy expenditure

actual exercise

nonexercise activity

NEAT:

any activity involving muscle contraction

activities of daily living

Energy expended depends on activity intensity and duration

• Usually expressed as a ratio or percentage of basal energy expenditure

• Laboratory measurements:

–calculate kcalories used per minute of activity for various body weights

–heavier person expends more energy in same activity than a lighter person

Predictive equations:

estimate energy intake

equations based on height, weight, gender, and age

high margin of error

based on healthy, normal weight individuals

altering equations leads to more inaccuracies

no established equation for older population

Relationship between energy intake and energy expenditure

Balance fosters weight maintenance

Negative energy balance:

insufficient energy to support needs

causes: insufficient intake and/or increased expenditure

Positive energy balance:

energy intake exceeds needs

causes: increased intake and/or decreased expenditure

Individual differences

Influence of biology and other factors on appetite, satiety, and metabolism

Low levels of activity prevalent

Increased intake widespread

Goals of national recommendations:

reduce obesity

provide adequate energy

Estimated Energy Requirements:

recommendations for population groups

role of registered dietitian

no advice supporting weight loss/weight gain

Excess energy consumption compared to needs

Interventions when weight gain increases disease risk

Target energy consumption or expenditure contributing to imbalance

Nurse’s role in intervention:

explore sources of kcalories and “empty” calories

brainstorm ways to create deficit

find opportunities for physical activity

Socioeconomic levels tied to positive energy balance

Importance of education

A positive energy balance results from caloric intake exceeding energy expenditure, ultimately leading to weight gain. Children who do not engage in much physical activity tend to have a higher weight than those who are active. Impaired glucose tolerance may result when there is excess weight but it tends to develop over a period of years.

Result of insufficient energy consumption and/or excess physical activity

Intervention necessary when health risks increase

Target aspects of consumption or expenditure contributing to imbalance

Team approach

Nutrition assessment

Assessment of physical activity levels

Elevation of metabolic response

Avoidance of predictive equations

Use of indirect calorimetry or modified approach