First, to respond to your post 273, yes, consuming more calories than you burn does indeed make you fat, and I agree, it is that simple. The problem is, it's all too easy to exceed your caloric limit (I don't count calories, as the saying goes, but calories DO count) if fats and proteins are the central part of your diet. Two thousand calories a day (or whatever) doesn't go far in the form of meat and butter. Reduce fat and protein, especially the former, and you can eat a LOT, never be hungry, and stay under your calorie limit. But more importantly, just consuming the right amount of calories isn't enough, as I'm sure you know -- vitamins, minerals, fiber, that sort of thing. I'm not one of these people who advocates eating nuts and berries and tree bark or whatever; a reasonable balance is far preferable.
Now, as to the ill effects of too much protein... while obviously not as bad as overconsumption of fat, too much protein can interfere with the absorption of minerals, can raise blood sugar levels, can raise uric acid levels (leading to gout), and is linked to higher incidences of cancer. The biggest problem to me, however, is that high protein foods are so often high in fat.
It used to be commonly believed that the more protein you ate, the stronger you'd be, period. The training tables of college and pro athletes used to permit/encourage literally unlimited meat comsumption. That's no longer the case. Far from somehow "burning" fat, excess protein is stored by the body as fat.
I'm no monk, believe me. I enjoy a nice rare New York strip as much as, if not more than, the next guy. But I make a conscious effort to limit those occasions.
Here's a quote:
"Adaptive changes in metabolic rate in response to low caloric intake relies on complex and highly redundant readjustments of the thermoregulatory system including both behavioral and physiological regulations, and acting on both heat loss and heat production. It contributes to the rapid replenishment of fat stores as soon as an adequate amount becomes available again. It thus has a survival value in subsistence societies societies. In affluent societies it is a source of despair for the obese and of fortune for the authors of slimming programs." (IJO 1993 17 (Suppl 1) S3-S8)
In addition, there are studies that suggest high fat content does not cause obesity. From the same link, comes:
"There is no epidemologic evidence indicating that total fat intake per se, independent of total caloric intake, is associated with increased adiposity in the population. Obesity itself has not been found to be associated with dietary fat in either inter- or intra- population studies. ("Diet and Health: Implications for reducing chronic disease risk"; Committee on Diet and Health Food and Nutrition Board Commission on Life Sciences, National Research Council; National Academy Council, Washington D.C. )"