Tuesday, July 16, 2013

Food combining


Dear Mark,
I have heard two competing ideas on food combining and insulin release/fat storage. One says that you should combine high carb foods with fat or protein to minimize insulin spikes.  The other says that you should eat carbs by themselves because the insulin stimulated by the carbs will also store protein or fat as fat if eaten in the same meal as carbs. Which theory is correct and does it really matter for health/weight loss?
Thank you so much!

 For the most part, there’s no need to separate fats from carbs from protein in a normal meal with reasonable amounts of calories. In one study, researchers put patients on one of two hypocaloric diets: either a balanced diet, where fat and protein and carbs were eaten together, or a food combining diet, where macronutrients were consumed mostly separately. Both groups lost the same amount of weight, though people who ate macronutrients together achieved better blood pressure numbers and lost slightly more fat. Those were low calorie diets, however, not massive ad libitum feedings. If you’re eating normal amounts of food (i.e. not stuffing yourself or purposely overfeeding), I see no reason why some sweet potato fries cooked in coconut oil or a bowl of Greek yogurt and berries will do any harm. Your body doesn’t have to handle extra energy, so switching between fuel substrates isn’t much of a problem.
When overfeeding, whether on purpose or inadvertently (the buffet effect), macronutrient selection begins to matter. One of the reasons why I recommend that folks doing a carb refeed for weight loss limit fat for the duration is that overfeeding with carbs boosts leptin and energy expenditure, while overfeeding with fat does not. It’s also why bodybuilders typically follow their workouts with a super high-carb, high-protein meal – to spike insulin and shuttle nutrients into their gaping, starving muscle cells – and go lower carb and higher fat on rest days – to keep fat burning elevated. As a general rule, burning massive amounts of fat precludes burning massive amounts of carbs, and vice versa. Plus, there’s the simple fact that carbs and fat are incredibly tasty together – think pizza, cookies, ice cream, french fries, and so on. Fat alone or carbs alone aren’t very appetizing, but combined they definitely promote overeating. That’s not a problem for people who want to gain weight, or have no issue with incredibly tasty foods, but it bears mentioning. For an idea of the long term effects of a high-carb diet with significant amounts of (bad, refined, seed-based) fat, just look at the obesity rates in America.


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