My intuition tells me the following:

Let's assume on top of my regular diet, I eat a cupcake and as a result of eating that cupcake I put on 50g of fat. Now lets let's assume instead of eating one of those cupcakes I ate two instead.

To me it does not follow that will mean I will put on 100g of fat instead of 50g. It seems too simplistic and probably not how the body works, although my friends adamantly argue that it will mean exactly that.

Similarly I believe that I would gain more weight from eating a pizza, if I ate it one slice per day on top of my regular diet, rather than if I binged out at one time and consumed it all in one night. Again I can't really defend this idea, it's just intuition.

Is my intuition correct? If so, why, and what evidence can I show my friends to prove my case?

  • While diminishing returns are a thing, I imagine that in an ancestral environment of scarcity, any gene that let you hang on to a big meal and salvage every calorie out of it would be highly advantageous. I was going to say that nutrition questions aren't allowed, but darned if you didn't find an appropriate batch of tags. – Noumenon Mar 2 '15 at 4:16
  • Where is there any fitness related information in this question? Straight nutrition unrelated to exercise is off topic for the site. – JohnP Mar 2 '15 at 14:55

The body is very good at consuming calories, especially carbs. Eating large amounts of fat takes a bit of adaption until it's 100%.

Eating more does increase your energy expenditure though, and it does so in many different ways. One of these is non-exercise activity thermogenesis (NEAT), which increases as energy intake increases, i.e. if you eat more, you will do more activities that you are not aware of, such as fidgeting and so on. (1)

You will also waste more energy when doing planned exercise (2)

Except for these two reasons, eating more will also make you add muscle and fat, which increases your total energy requirement in the long run, won't be affected by one cupcake though :)

I think the first part is very interesting, it could explain why exercising makes you feel more calm and focused.

[1] http://www.ncbi.nlm.nih.gov/pubmed/9880251

[2] http://www.ncbi.nlm.nih.gov/pubmed/19889869

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