[Thorondir]

My five children (mostly adults) and I eat tons of sugar and none of us are fat at all, because we exercise like maniacs. We don't exercize because we are health fanatics, but because we enjoy working out together or alone, for that matter. And we are not fit because of genetics. My parents and two of my sisters are fat. Whenever I slow down on my exercise routines, I begin to pork up, so I just don't do that. At 44 I can still wear a leather belt I wore when I was 16.

It's the exercise, folks. If you exercise a lot, you can go on an eat-all-you-want diet. It works for me and everyone I know, except for one of my sisters. Her thyroid is screwed up. She really has to fanatically diet and exercize to drop the flab, but she did it once and proved it beyond a doubt with her (temporary) cute little figure.

[King Prout]

I will go so far as the following:
While in Basic Training, I simultaneously lost two inches around my waist and gained about 30 lbs.
A lot of folks go nuts equating BMI-based "overweight" with actual medically hazardous obesity, totally neglecting to factor in the much greater mass per-unit-volume of lean muscle versus fat.

[King Prout]

Oh, and those maniac DI's crammed about 9000 calories down my gullet every day, because they believed that I was "too damned skinny" They were right, and it worked... Eating like a pig plus an intensive exercise regimen did exactly what they intended it to.
Conversely, their method of dealing with obese trainees involved intensive exercise and a heavily restricted diet. It never turned an obese recruit into a sleek snake like me, but it DID render them fitly "overweight" rather than obese... in the cases I observed. I do not know what their success rate was, nor how permanent the overhauls were.
That sort of strict and sudden regimen would not work with a massivly obese patient who has begun to suffer the secondary effects of chronic or morbid obesity. It'd kill them.

[Rennes Templar]

You may be trim and fit, but don't expect to have pain free joints in 5 to 10 yrs consuming all that sugar!