ELI5: what would happen if a morbidly obese person starved themselves? Would they live longer than an average weight person who did the same?

Fun fact: Overweight people (not morbidly obese - about 40 pounds overweight) tend to do better when they get into accidents or are slammed with a critical illness than normal/underweight people because they have the stores to get them through 30-60 days of hanging onto the edge.

My mother is a perfect example of this. She weighed 180 lbs when she became sick. It took the doctors three months to figure out that she had Grave's Disease and was having thyroid storms. Despite eating her standard diet of meat/veg/carbs supplemented with entire boxes of Hostess snacks and up to 8 candy bars a day (she'd freak out if she didn't. She was starving to death) she still lost more than 60 pounds and was so frail toward the end.

But she survived. A woman starting out in the 120's would not have have made it three months.

This is just one personal antidote, but the science does back this up. In general, overweight people have much better five and ten year morbidity outcomes than any other group. They aren't so obese that they risk significant increases in heart disease and cancer, and they have some padding to catch them if they have an accident. There is a movement in the medical community to reflect this in the BMI charts. (I read one doctor who didn't want the change because he was fighting hard enough to get people from obese to overweight.)

/r/explainlikeimfive Thread