system
Given the following post, respond as if you're commenting on Reddit:
human
[LotR] Are there fat elves?

Does elven biology even allow them to become overweight? Can an elf suffer from cardiac disease?  Would a fat elf sink in the snow?
gpt
Deep inside our human psyche there is an innate fear of death. This motivates our biological drive to consume more than we need, because there is a fundamental anxiety in our nature that there may be a future point where we don't have enough.

To an immortal, if there is not enough food later on it's not a big deal. They can't die, they're just uncomfortable until they get fed again. Their appetites work differently from our's. In this way, all their biological drives are naturally tuned to be more moderate. They don't crave non-procreative sex, because they don't need to adopt a high-productivity reproduction strategy. They don't crave excessive amounts of food because they don't need to fear starvation. 

This is why some of the half-elven choose to be mortal. The knowledge that things may have an end makes all the highs and lows of life more intense.