system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] What would happen if Ant-Man shrunk himself, ate enough food (relative to his size) to get him full and then grew back to normal? Will he still be full?

Does the food grow as well as him? Does he stay full? I need to know.
gpt
In the MCU, I'd say probably, but he wouldn't be getting much energy from the food.

Pym explicitly states at least twice in the movie that the technology works by decreasing the **space between atoms**. That means that tiny Ant-Man has the same *number* of atoms as regular sized Ant-Man. Our bodies need food so that our mitochondria can respire and make ATP. 

The amount of energy you need is proportional to the number of cells you have. And because tiny Ant-Man has the same number of atoms as regular Ant-Man, he has the same number of cells, and therefore has the same energy requirement.

Now, if Ant-Man ate a crumb while small, his stomach would get full. And when he increased back to regular size, that crumb would also *probably* increase in size proportionally; therefore Ant-Man would still have a full stomach. **But** by the same logic of Pym particles stated in the movie, making an object larger would not increase the number of atoms, it just increases the **space between atoms**. Therefore a crumb would not provide any extra nutrition after being expanded. 

If an item of food could be expanded and the process increased nutritional value proportional to size, wouldn't Pym have tried to exploit that trick to solve world hunger? The answer is no, because that trick would violate the first law of thermodynamics (conservation of energy), and so it does not happen. Expanding food does not increase the *number* of atoms, therefore it does not increase the nutritional value of an item of food. If a regular-sized person ate an expanded food, they would feel full without having consumed as many calories - probably a great idea for a line of diet foods.

I don't know what the Marvel comics explanation of Pym particles is, but in the movie universe, the answer is - **yes**, grown Ant-Man would *feel* full, but as the growth process does not provide any extra nutrition, his body would only absorb the amount of energy that was present in the original tiny piece of food.