Why is it, that you can eat a 2,000 calorie meal, and in theory, you shouldn’t need calories again until the next day, but you can be hungry again 6-8 hours after you finish eating? Is your body just not capable of actually processing that many calories?

Question

I think the title kind of says it all, but I watched a video of someone eating a 2.1k calorie burger, and his friend said, good now you won’t need to eat for 24 hours and they laughed, then I thought, ” wait why is it that you would be hungry again after 6-8 or so hours, is our body that inefficient with those calories? Does this mean that when you eat over a certain limit of calories you body just puts the rest into waste and some into fat? How does it work?

Update: Wow thanks for all the upvotes, awards, and comments. I really appreciate all the new information and help on this topic.

In: Biology

Answer 1

I think your question comes out of a misunderstanding of how efficient your body is and what calories are. The hunger you feel is mostly driven by literally how full you are and also other things like how much you think about food, how thirsty you are, how hard to digest the food you eat is.

When it comes to calories, the word represents an amount of energy we get out of food when digested. The way we find out how many calories a food has is we burn it and see how much heat is created. Calories are stored in the body in different ways but the vast majority of the excess is stores in fat cells.

When we eat a burger with 2000 Calories (kilocalories) we pretty much absorb all those calories. From the literature I’ve read, bodies are very efficient and pretty much absorb all the calories +/- 5%. The most inefficient bodies absorbing 5% less and the most efficiwnt absorbing 5% more. Obviously we can’t absorb more than the amount of Calories available so you can disregard the + if you know exactly what’s in the burger.

Now bodies are built to be able to store energy to use when food isn’t available so if we did not feel hunger outside of caloric need, we would be in trouble if food became scarce. Therefore, as soon as our bodies are physically able to accommodate food, we will feel hunger. That’s why people say you should have more fibrous food when on a diet. It’s because it takes longer to go through you, keeping you fuller longer.

There are some weird things that happen after you stay hungry chronically where you feel it less and less but I don’t have expertise in that so I’ll leave it for someone else.