energy and nutrients Flashcards
adequate nutrition for:
required for
provision of energy
regulation of metabolism
promotiom of growth and development
essential nutrients
ones that your body cannot produce (or not to an adequate amount) and must be provided by diet
micronutrients- vitamins and minerals
macronutrients- carbs, fat, protein and water
energy
required to fuel many different body processes, growth and activities
energy is obtained by the oxidation of macronutrients provided by food and drink we consume
brain uses ~20% of body’s energy
energy intake
defined as the energy content of food + drink ingested as provided by the major sources of dietary energy
different foods provde different amounts of energy for a given weight
atwater general factor
determining energy content of foods
uses a single energy value (factor) for each macronutrient
based on the average heats of combustion of each food group and corrected for losses in digestion, absorption and urinary excretion of urea
calculated from the amounts of macronutrients in foods eg carb 4kcal/g, protein 4kcal/g fat 9kcal/g alcohol 7kcal/g
energy expenditure
total is comprimised of 3 components
resting/ basal metabolic rate (RMR)
activity energy expenditure
thermic effect of food (TEF or diet induced thermogenesis)
RMR
energy required to sustain the biochmeical systems of the body at complete rest
accounts for ~70% of TDEE in sedentary individuals
fat free mass is highest determinator in RMR
differences in RMR
infants and young children have higher RMR due to rapid growth and development
males have higher RMR than females as they tend to have more muscle mass
older adults have lower RMR as muscle mass decrease with age
active energy expenditure
most variable component of TDEE
activity level and efficiency at which exercise is completed
active energy expenditure estimated to range from 15% in sedentary individuals to 50% in highly active individuals
determinants- genetics, age, sex and environmental stimuli
thermic effect of food
TEF
EE that relates to food consumption- energy required to digest, absob, assimilate and store nutrients
dependent on amount and type of nutrients consumed
western diets- TEF accounts for ~10% of TDEE
changes in energy requirements
infants, young children and teenagers need proportionally more energy for their size to grow and be active
energy requirements decline in adulthood but actual needs depend on individual’s activity levels
for adults energy requirements decrease as activity levels fall as there is a reduction in basal metabolic rate
energy requirements
contributions of macronutrients to EI
carb=50%
fat=35%
protein= 15%
energy men vs women
energy requirements change throughout the life- different ages need different amounts of energy
throughout life it is generally higher in men due to greater muscle mass
energy balance
balance between how much energy is consumes and how much is expended
state of energy balance- individuals who maintain their body weight over a sustained period
energy imbalance
positive energy balance:
energy consumed>energy expended = results in weight gain
negative energy balance:
energy consumed< energy expended =results in weight loss
increased risk of osteoperosis, infertility + heart failure
