The thing is, it’s both bullshit and strictly false. There’s always some amount of food energy that goes in your mouth and comes straight out the other end, and this varies based on a host of poorly-understood factors.
Edit: I’m arguing against the extremely common assertion that energy eaten = energy expended + weight gain, which is what your original comment looked like. If you’re talking strictly about fat cell behavior, you’re right, but this is rather useless information for the purpose of weight loss. What SoullessAutomaton said was energy eaten >= energy expended + weight gain, which is indeed true.
The thing is, it’s both bullshit and strictly false. There’s always some amount of food energy that goes in your mouth and comes straight out the other end, and this varies based on a host of poorly-understood factors.
Edit: I’m arguing against the extremely common assertion that energy eaten = energy expended + weight gain, which is what your original comment looked like. If you’re talking strictly about fat cell behavior, you’re right, but this is rather useless information for the purpose of weight loss. What SoullessAutomaton said was energy eaten >= energy expended + weight gain, which is indeed true.
If you have diabetes mellitus you lose a lot of glucose in your urine. Certainly that simple case complicates the energy in energy out dogma.
“out” would have been a better word than “expended”—to cover all the ways that energy can leave your body, including glucose in the urine.