Basically it's a fad.
When you do a Google search on "food combining" you end up with a lot of sites that sound very authoritative but for the most part, they're usually selling their diet program...keep in mind that often these sites utilize Search Engine Optimizers to maximize the chance that their site will be listed at or near the top of page 1 of any search results...so it won't necessarily be the CORRECT information or UNBIASED information...
That said, as far as I know, there is really no scientific basis for food combining as a way to lose weight.
Quick and Easy Weight Loss, Is It For Real? - the practice is mentioned here as 'junk' diet advice.
From what I've seen, a lot of the hype about food combining began back when the book
Fit For Life came out. You
can find an article about the book/program here.
From the
UC Berkeley Wellness Letter:
Quote:
Forget about "food combining." There's no evidence to support claims that it's vital to eat foods in the right combinations—never combining, for instance, carbohydrates and protein at the same meal—or that fruits should always be eaten raw and alone, because otherwise they will ferment and turn toxic in the stomach.
The Myth of Combining Foods Properly (from the Kansas State University Foods & Nutrition Digest):
Quote:
A myth that never dies is the myth of food combining, that is, it's important to eat foods in the right combinations. One such taboo is eating carbohydrates such as starch or sugar in the same meal as high protein foods. Furthermore, it is better to eat fruits raw and alone because otherwise they will "ferment and turn toxic in the stomach." This kind of nonsense works best with people who have little idea of what constitutes food and how their bodies work. Food chemistry and composition are a mystery to them. They don't understand how a common food like bread is a combination of starch, protein, a number of minerals and vitamins including most of the B vitamins. If you eat the whole grain (the brown wheat kernel with the germ that can sprout), you'll also get considerable fiber from the outer brown layers and some fat and vitamin E from the germ. Other ingredients in bread usually include some sugar, fat, and salt. Thus foods are combinations of nutrients and many other natural chemicals...
Here's a study from Pubmed, titled
Similar weight loss with low-energy food combining or balanced diets - where they put study participants on either food combining or a balanced diet to see what the results were:
Quote:
CONCLUSION: In summary at identical energy intake and similar substrate composition, the dissociated (or 'food combining') diet did not bring any additional loss in weight and body fat.
(
here's a link to an article about the same study, only written in laymen's terms)
Lastly - An excellent summary of food combining written by Australian dietician Glenn Cardwell can be found on
page 22 of this PDF. I especially enjoyed the bit where Mr. Cardwell points out that if you can't digest protein and carbs at the same time, why don't women have one breast labeled 'protein' and the other 'carbohydrate' - as breast milk is a blend of protein, carbs and fat!