@JLeslie: If you read my answer you’ll note that I attempted to answer in the first sentence. “I don’t know because fat isn’t the only thing we need to live.” I will elaborate more. We need many other nutrients to live that we get from food. Someone who is underweight as it is would probably die faster, like someone who is anorexic. However, someone who is average weight, like me 130–140 pounds, 5’3 might not necessarily starve to death first. However, since I would imagine that obese people have slower metabolisms or else they might not have gotten fat in the first place then, yes, it is possible that an obese person would take longer to starve to death.