I would have to eat a LOT of junk food for an extended period of time to push myself into the overweight range, much less the obese range. I'm kind of itty bitty. x3 So I don't really worry about that-- especially since I don't really care if I look "chubby" by society's (somewhat unrealistic) standards, as long as I'm healthy. The chances of me having weight-related health issues are virtually nonexistant, considering my genetics and eating habits.
However, I do try to watch what I eat. I may not worry about my weight, but I do like to make sure what I put into my body is actually good for it so I can feel energized and stay healthy in the long-run (and not end up in pain, in the short-run). That, and I have a hypersensitive stomach. I have a hard time eating anything too rich, greasy, or spicy without getting a stomach ache, so I tend to live on things like carbs (potatoes, whole grain bread, noodles, etc.), poultry, and fruit, which are inherently fairly healthy foods. They taste good, too-- added bonus of healthy things that weren't formulated to be "sugar free" or "fat free" or "diet" or whatever other weird-tasting nonsense-alternatives they have out there.