I think a lot has to do with age and genetics.

I'm not fat but my weight can move 5 -8 lbs. a week depending on how much exercise and what I eat.

Fruits are ok, but contain lots of sugar.

Veggies are great, but aren't very satisfying.

If you can cut down on starchy stuff and fried/fast food you will be ok.  Plus booze really puts it on.

When I was skinniest I was juicing...one can really lose the weight but it's a pain buying fresh stuff and nutritional additives.