Quote[/b] ]FWIW, separating carbs and fat isn't going to be of benefit in my opinion, for the following reasons:
1. Eating carbohydrates without fat will not lessen the chance of fat storage. It is now known that, in the case of caloric excess, carbohydrates can be readily converted to fat via de novo lipogenesis.
2. Eating fat without carbohydrates shouldn't make a great deal of difference either, assuming the same amount of calories. There are multiple mechanisms for fat storage that are independent of insulin. If you have lower insulin levels over a long period of time you will lose fat, but separating carbs and fat isn't going to reduce your total insulin levels, just make them lower for some parts of the day and higher in others.
3. What we want is stable blood sugar levels for most of the day. Coingestion of fats and carbohydrates helps with this, as fat will generally decrease the glycemic and insulin response to a meal. If you separate carbs and fat, you will have lower insulin/blood sugar levels for some parts of the day and higher levels for others; it is this roller coaster ride which is precisely what we want to avoid.
4. I believe that the reason people often experience results from such diets is not because of the macronutrient manipulation per se, it is because it forces them to avoid the worst foods, which are generally high in both carbohydrates and fats, whereas healthy foods have a tendency to be high in only one or two of the macronutrients. Take a list of some of the healthiest foods and their predominant macronutrients:
Vegetables (carbohydrates, sometimes fat)
Fruit (carbohydrates)
Meat (protein, fat)
Low fat dairy (carbohydrates, protein)
Low GI grains (carbohydrates)
Protein powders
Healthy oils
The only real exception is beans and nuts, although these still tend to be particularly high in two of the macronutrients. In contrast, almost every junk food is high in both carbs and fats. So, IMO, it is safe to say that one doesn't have to worry about separating carbs and fat, but one should worry about just eating clean.