You mean other than the fact that I have a degree in nutrition from an accredited university, and have over a year in chemistry and biochem under me from that, and the fact that I'm not pitching a new fangled diet...hmm let me think. There are blogs, etc out there that tout that you burn more calories and lose weight with these negative foods. Just as there is opposition. With that being said, take into consideration the fat lose claims. eat more veggies and lose fat. Well of course, veggies and fruits are fiber low-cal (mostly) fiber containing foods. This means that the more you eat, the more a sensation of fullness you get and by default the less of other foods (fats, some proteins) you eat, creating in essence a calorie reduction in your diet. Same goes for the high protein diets. You replace carbs with protein. Protein makes people feel fuller longer thus over the course of the day generally eat less calories than if they stuck with their high carb normal diet. In general, this is a basic premise.
they are not negative calorie foods. As a matter of fact there are no real negative calorie foods. Unless it's 100% cellulose.
vegetables are very very fiberous, as you mentioned. their very small amount of calories are intertwined deeply in natural fibers and water. the digestive process to release those calories is very thermogenic(comopared to oher foods), because the body has to get through all the fibers. the amount of calories that it takes to digest a vegetable like broccoli is more than the amount of actual calories that your body will get out of broccoli.
that alone makes them fat burning and negative calorie.
now there is absolutely no proof of that fact... no way to measure calories for digestion...
BUT
beyond that argument, there are soem facts
vegetables help balance ph levels. with veggies your metabolism will be better becase it wont be pulling calcium and glutamine from muscle and bone to balance the bodies ph. without a balanced intake of ph foods, your body will be somewhat catabolic, regardless of how much your eating..because it has to balance the ph on its onw, which means it has to release catabolic homrones t signal the release fo glutamine and calcium form muscle and bone... two things which are required for the bodies ph balancing process.
vegetables, even though they contain glucose, actually lower resting insulin levels. the fiber contained vegetables isnt digested, but the bacteria in the intestines feeds on the fiber and sends short chain fatty acids to the liver as a result of that feeding.. and when the liver recieves these SCFA's it in turn lowers its out put of glucose and lowers the release and levels of insulin.
fibers also have the possibility of potentially increasing insulin sensitivity, have the ability to clean up the digestive tract to promote better protein digestion, and..as you mentioned, help the mind feel well fed on a small amount of calories.