re: PuttaDaForkDown

You can't say either are 100%. Sure I could eat whopper's every day for a month then switch to a healthy balanced diet and I'll loose weight. But it's because my body isn't taking in crap anymore. I'd say diet is 75% and exercise is 25%. It depends on the type of exercise you a doing as well. Lifting a certain way will have you gain weight due to muscle build.
And the amount of sweating has nothing to do with it. It's all about keeping your heart rate elevated for an extended period of time.

Tl;dr: I disagree. I say 75% diet, 25% exercise