L8 Energy Balance P1

what is basal metabolic activity

the enrgy used to maintain normal body function

how is obesity caused

when more energy ingested than expended/ used

what is basal metabolic rate

• rate of energy use required to maintain vital body function in thermo-neutral environment (20 degrees)

• meaured after an overnight fats

• humans 1400-1800 kcal a day

when food is metabolised it splits into

• heat → by product lost in exercise

• work energy → kinetic energy to move things

• stored as chemical energy → e.g in phosphate bonds in ATP, nucleic acids ..

in cell whar is main carrier of trasferable energy

ATP

• breaking Pi bonds releases Gibbs free energy

• break bonds usuing water

• produced in glycolysis and oxidative phosphorylation

what is energy measured in

Joules (J)

what is basal metabilic rate proportional to

lean body mass ( everything ecept fat)

variations in basal metabolic rate

• children higher BMR than adults

• age decreases BMR - as muslce loss

• males higehr BMR thans femaile sas have more muscle

ways of measuring metabolic rate

Direct calorimetry

• sit in calonetry chanber which detects the amout of heat released by body

• Kilocalorie

indirect colorimetry

• measures o2 and co2 levles to estimate enrgy exepnditure and fuel usage

Respirtaory exchange ratio

V of CO2 produced per min/ vol of o2 consumed per min

what happens with the food you consume

where is most nutrients stored

Adipose tissue → muscle → liver

carb uptake

differnet tissues uptaek glucose in difefrent ways

• carbs broken donw inot sugars

• excess glucose stored as glycogen in liver and msucles

• or can be converted into fat and stored in adipose tissue

why is insulin improtant

without it cannot store glucose and so cannot use it to increase sugar levles break donw fat and muscle

insulin effects