Energy content/energy value of food

Question 1

Energy content and energy value are measured in…

Answer 1

kJ per g/100g/mol (if pure)

Question 2

is the energy released during combustion for most foods similar to energy released during cellular respiration when oxidised?

Answer 2

yes

Question 3

Define: energy value

Answer 3

(energy available to the body from a nutrient/good

Question 4

Energy content/value of carbs?

Answer 4

17/17

Question 5

Energy content/value of fats and oils?

Answer 5

39/37

Question 6

Energy content/value of proteins

Answer 6

24/17

Question 7

Why do fatty acids have higher energy content/values than carbs?

Answer 7

Check: they tend to need more O2 than carbohydrates to be oxidised, and so have an increased potential for oxidation and more energy is released.

Question 8

Reasons why energy content is greater than energy value?

Answer 8

o Incomplete absorption of nutrients of body after food is digested
o Incomplete oxidation of nutrients (eg. proteins/insoluble fibre)
o Heat loss during combustion.

Question 9

Example of how energy available to body can vary between nutrient groups?

Answer 9

for carbs, energy value of glucose is much higher than cellulose, which can’t be digested

Question 10

how to calculate energy values of food?

Answer 10

o Incomplete absorption of nutrients of body after food is digested
o Incomplete oxidation of nutrients (eg. proteins/insoluble fibre)
o Heat loss during combustion.

Question 11

does water have energy?

Answer 11

nop