system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Will a fat person survive longer without food than an average weighted person?

Does fat have an advantage after all ??
gpt
Usually, but not always. They'll die of straight-up starvation much later. However, people are more likely to die from secondary problems like electrolyte imbalances and vitamin/mineral deficiencies before dying from organ wasting to the point that the organs no longer function. And while being fat doesn't necessarily mean one's heart is less healthy and more susceptible to potentially fatal arrhythmias, it IS an additional risk factor.

So all else being equal, Average Adam's body will start burning vital organ tissue sooner, but Fat Frank's organs were already a bit more stressed and he's more likely to have a heart attack when electrolyte problems set in, so Adam could still survive longer.

People have died of starvation at high weights due to those secondary problems after not eating. Our bodies are adapted to storing fat for energy to get us through famines, but even during a famine, it's very rare that there's absolutely nothing at all to eat for very long periods of time. Typically, it means food is scarce, not absent. You can live much longer on very little food than none at all.