Each person needs a different amount of energy depending on factors such as:

​Food can be burnt to see how much energy it contains

​1. Weight a small piece of dry food then put it on the top of the mounted needle
2. Add a set volume of water, measure it temperature
3. Hold burning food under the boiling tube
4. Measure the temperature of the water again after the piece of food goes out

​Calculate the amount of energy in the food using special formulas:

​Variables:

​Dependent
not controlled, the effect of independent factors

​Independent
under the researches control, can be changed

Make an effect on dependent variable

​Digestive enzymes - break down big molecules into smaller ones