How to reduce heat loss?

Question

I am going to do a chemistry experiment that is about fuels.

My experiment is about burning food and use the energy produced to heat the water. Thus, I can use mc△T to calculate the energy of the food produced.

However, I have a question. I want to know how to reduce the heat loss so that I can ensure most of the heat energy produced by food can go into the water?

P.S. My experiment is like this.
http://www.woodrow.org/teachers/chemistry/institutes/1988/calorimeter.gif

Answer 1

I don't understand how burning food produces energy that would heat up water, but I'm gonna say to keep the holes that you puncture in your can, small and perhaps center your food and burner under the can as much as possible. Not sure what else to tell ya, but Good luck, and if it works lemme know!

Answer 2

If it is possible, wrap the sides of the can with insulation and place insulation on top of the can also. The insulation would have to be something that will not burn. If you have access to large amounts of glass wool, that would be good to use.