if calories in > calories out = weight gain, then what does metabolism have to do with anything?

Question

How does someone’s metabolism impact the calories consumed vs calories burned equation?

In: Biology

Answer 1

One option is how much calories you take out from the food. Let’s say you read the label that this food has 100 calories but your metabolism only takes 90 from it. It would be a shitty metabolism in a famine but at these times of over-eating this saves you from weight gain. It can come from less efficient digestion or less efficient conversion of food. Anyhow just produce less energy from the same amount of food.

Another option is that your metabolism heats your body a bit more than usual. More heating is a bit more on the “calories out” side of the equation. It can come from actual heating or more heating while workout or more sweating. Whatever loss of heat.