How come weight is affected by calories, and not the weight of the food? If I eat a bag of candy, I will gain weight, but if I eat 4 apples, I won’t gain as much?

Question

How come weight is affected by calories, and not the weight of the food? If I eat a bag of candy, I will gain weight, but if I eat 4 apples, I won’t gain as much?

In: Biology

Answer 1

Organisms have different abilities to extract useful energy from food. Cows, for example, can extract more useable energy for grass than a person could. The actual weight comes from the mass of the ingredients not from their ability to be converted to usable energy by our bodies. Caloric density is a helpful concept. How many calories per gram. There are a lot of things in food (like water and fiber) that contribute to its weight but not it’s calories. You will gain weight in proportion to the usable calories you consume whether from apple or candy. 4 usable calories of apple is equal to 4 usable calories of candy.