dzuljas, the concept of not eating fats and carbs together is a modern trend in bodybuilding that is very unscientific. For one thing, you should NEVER eat a meal that doesn't contain fats. Evidence shows that eating a lowfat meal (20% of the calories from fat) will lower testosterone production and elevate shbg (something even steroid users should worry about on cycle). This can lead to a reduction in fat loss, and can impede gains in lbm while bulking, and cause muscle loss while cutting.
Now as far as eating carbs and fat together causing gains in bf, this is rediculous. The idea is that the body tends to burn fat or carbs as a fuel source, and it will burn carbs in preferance to fat (interesting theory but false), so it will use the carbs as fuel and store the fat. Ok, so you remove the fat and just eat the same number of calories from carbs. You get a faster rise in blood sugar (the lower the fat content of the meal the HIGHER the GI, you can lower the GI of foods by adding fat) and a larger insulin spike. This is caused by the precence of more carbs and the lack of fat to slow absorbsion. So, you eat the same number of calories, but absorb it faster and have more insulin released. Insulin is your storage hormone. Higher insulin levels cause more fat storage. Thus more of the calories you just injested would be stored as bodyfat by eating a lowfat or no fat meal than had you just eaten a mix of fat and carbs.
Now this theory gets even sillier when you consider the fact that low gi carbs, are still digested and absorbed faster than fats eaten in the same meal. So you will get the rise in blood sugar and the insulin spike prior to the fat being absorbed from your intestine and into the bloodstream. So in all actually, if this theory of the body burning either fat or carbs, and prefering carbs thus storing fat, the fat you ate in the fat + protien meal would be entering the bloodstream at while the carbs from the carb + protien meal eaten a few hours later was being eaten, thus you would gain fat from it. So these eating plans where you eat 6 meals liek this
Meal 1: carbs + pro
meal2: fat + pro
meal 3: carbs + pro
meal 4: fat + pro
meal 5: carbs + pro
meal 6: carbs + pro
Would be extremely fattening during meals 3 & 5. Fortunately, their theory is wrong so it doesn't happen like that. In any event, it is far more complex than this, but anyone who knows basic nutrition can clearly see how utterly rediculous this idea of not eating fat and carbs in one meal is.
::slips into his flame-resistant suit::