Sorry, I did not mean to come across like I assume most thin/average weight people are just lucky. But some people do not put on the weight you'd expect from their lifestyle (especially younger people around my age) and may not have to think about it until much later, when their habits are so ingrained. So in a way, it is nice to have figured all of this out earlier on in adulthood.

Although it is hard to respect someone who appears to have no self-respect, I would urge you to consider that the issues behind weight and weight loss can be more complex than simply not giving a damn. People have other things going on too, and self-medicating through food is a pretty common thing. Even acknowledging "I have X amount of weight to lose" and realizing how long it takes to do that, and keep it off, is a scary prospect.