I’d love to see your take on the validity of the metabolic type diet. I have found that a primal-style eating plan similar to yours works wonders for me, but I have seen some people comment that they maintain lean bodies with a very different approach than you. One commenter even stated that he gains weight when he increased fat calories. It seems like people can react differently to certain foods.
Metabolic typing periodically gets a boost in press every once in a while. The premise of typing suggests that people have distinctive metabolisms that are best served by a corresponding nutrition profile. Presumably, these metabolic distinctions are genetic differences based on your ancestors’ geographic origin. For example, if your ancestors are from the South Pacific islands, your nutritional needs differ significantly from those of the Lapps in Scandinavia, etc.
(Metabolic typing is different from the “blood type diet” you might occasionally hear about, but some people try to emphasize what they see as the overlap between the two “theories.”)
Traditional metabolic typing uses three categories: protein type, carbo type, and mixed type. As you can probably guess, “protein types” are supposed to eat protein- (and fat-) rich diets. “Carb types,” according to this theory, do well with a high carb, low protein and fat diet. “Mixed types” are supposed to thrive on equal parts proteins, fats and carbs.
And it gets more intricate/convoluted from there. Your “type” theoretically shows if your sympathetic or parasympathetic nervous system is “dominant” in your personality and physiology. Some of the tests and descriptions go into detail about everything from “fast/slow oxidation” to endocrine gland dominance. Supposedly, if you eat “according to your type,” you will finally be able to maintain good health and a normal weight. You can get long, exhaustive testing and reports that gives you this information, usually for a certain price. (Imagine that.)
What’s my estimation of this theory? Hooey, humbug, nonsense. But let me tell you why.
In last week’s post Did Grok Really Eat That Much Meat?, we cited research highlighting the substantial role that animal sources (fish/meat, fat/protein) played (and still play) in traditional hunter-gatherer diets. The study established a range of animal source intake between 45-65% of total energy intake. While the 20% difference isn’t exactly trivial, it’s still pretty minor in the grand picture.
It’s true people sometimes respond slightly differently to particular foods (like raw nuts, for example), and occasionally we find tolerance related patterns within particular ethnicities. An example of this pattern would be the fact that most of the world has a higher level of lactose intolerance than certain European ethnic groups. Nonetheless, we’re still talking about pretty targeted food sources. Despite these relatively minor patterns and individual issues, the fact is we all share the same biochemistry. (As in, our bodies all pump out insulin in response to carb intake….) Some people might be more sensitive to lectins, but lectins are still processed by those people’s bodies the same way they are by everyone else’s systems. The same goes for other food sensitivities, even those that may show a population-based pattern.
Let me say it this way. Having particular sensitivities to foods or preferences for foods doesn’t equate with the need for a different macronutrient composition in your diet. One size fits all may not be exactly right – there is a range. But that range is much narrower than the metabolic typing theorists want to suggest… We each might prefer to get our protein through a unique combination of meats and other foods (nuts, etc.), but we share the need for significant protein intake.
There are, indeed, other individual factors that influence our nutritional needs and sensitivities, but I’d argue that these don’t have anything to do with where Great-, Great-, Great-, Great- (and so on) Grandpa came from. They have to do with age, gender, personal medical condition and hormone balance, exposure to toxins and allergens, etc.
And then there’s the part about weight maintenance/loss. Sure, some people out there have a harder time gaining muscle mass despite their best efforts. Some people, while they’re perfectly healthy, have a harder time maintaining a “thin” physique. But a type report isn’t going to offer any new answers. Controlling your hormonal balance by minimizing carbs is the key. (And as for those people who eat carbs but look thin, they’re still throwing their body into hormonal havoc, despite their denial. Thin doesn’t necessarily equal health.)
Once again, within our individual ranges, we can all expect to achieve a healthy body by practicing what we know to be true over millions of years. At the end of the day, there’s undeniably a surprising consistency in our nutritional needs. A hunter-gatherer style diet (cornerstone of the Primal Blueprint) has held up time and time again as offering the best promise for true health and best protection against chronic disease.
Thanks, as always, for your questions and comments, and keep ‘em coming!