[cbloom]

1000 calories = 1000 calories in terms of weight gain/loss, if all other factors are held constant.

However, those calories have affects on your body other than just weight gain/loss.

As for fruit vs. pretzels -

fruit has more fiber & water so it's actually harder to eat as many calories as you get from pretzels, you get all the vitamins & minerals, perhaps the fructose provides more steady energy than the flour in pretzels dunno about that.

But yeah, generally the biggest difference comes from the fact that "all other factors held constant" is not usually done. If you eat 1000 calories of sugars you probably crash and eat again or aren't as physically active, maybe you don't consume enough protein and fat and vitamins, etc.

It's sort of a trick, just like the Atkins diet is really a trick. People lose weight on Atkins because they eat fewer calories, not because the calories are somehow better for weight loss. The diet says you can eat as much as you want, but the fact is that people can very easily eat a ton of calories on sugary starchy snacks, and it's just really hard to eat an insane amount of calories if you restrict yourself to meat veg and fruit.



(BTW I know people will talk about the thermogenic effects of some foods and so on - that is a microscopic factor in the scheme of things)