Genetics
Eat for the Muscle!
Your muscle fiber composition determines how your body metabolizes energy. Learn why there's no universal diet and how to find the optimal nutrition strategy for your body.
Genetics
Your muscle fiber composition determines how your body metabolizes energy. Learn why there's no universal diet and how to find the optimal nutrition strategy for your body.
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When it comes to diet trends, you can usually sit back and relax. The reason is simple: everything we do goes through an "evolution"—things that "fit" prevail. That's why we have (nutritional) trends. Hot today, forgotten tomorrow.
The reason these don't take off is that our biology gets in the way. Paleo, for example, is a solid template—but many Europeans simply can't live like an African hunter-gatherer for genetic reasons. It doesn't work. Let's connect the dots to low carb. The message from low-carb followers is: just "reprogram" your fat metabolism, and you'll automatically burn far more fat.
It's true that a person can, with considerable effort—say, through caloric restriction—enter an emergency metabolism mode that comes with a global, body-wide upregulation of fat-burning enzymes. Something similar has been observed in ketogenic diets. For one thing, you shouldn't confuse the relative proportion of fat-burning enzymes with the absolute amount of belly fat you actually lose.
But far more important is the question: are you forcing yourself into such a metabolism, or is it more or less the normal mode for your body?
Let's zoom in on, for example, the muscle fiber composition of individual people—the place where energy is primarily burned in the body—which is largely genetically predetermined (more on that shortly). It's striking how enormous the differences are.
There's plenty of variation, but we can distinguish three main fiber types:
Of course, fibers can partly transform into one another, so there's room for plasticity—that is, for change. But you should always keep in mind that metabolically (at the level of metabolism) and in terms of your contractile proteins and their properties, you inherit certain genetic preconditions. If you want to know which fiber types you're built with, consider which sport you most enjoy doing. That should give you a good approximation.
Anyway, here's an example: From sports science, we know that people of West African descent—more precisely, people with West African ancestry—have a very high proportion of fast, large Type II fibers. It's no accident that some of the world's best sprinters come from there, or why these people have an extraordinarily high muscle growth (hypertrophy) potential.
BUT: Studies consistently show that these same people have a significantly elevated diabetes risk compared to non-African control groups. That's because their muscles quickly become overwhelmed when, due to excess weight or excessive calorie intake, too much fat floods into the muscle cells. These Type II fibers can't buffer the extra load well because their basic substrate preference is glycolytic—that is, glucose-based—or they have only limited capacity to burn fat.
Given these metabolic constraints, these fibers can handle neither large amounts of carbohydrates (unless you're a sprinter) nor large amounts of fat. This results in a significantly elevated risk of metabolic disease. These fibers need:
If you try to "re-educate" these fibers with a ketogenic or fat-based diet, you're risking serious, possibly long-term damage. That's because their capacity to adapt to such a diet is extremely limited, and you'll almost certainly make things worse. Carbohydrates are always missing for optimal function—and fat isn't burned properly either.
Long story short: Maybe you're not West African. But the muscle fibers of these populations make an excellent model for understanding why your individual fiber composition has huge influence on which diet is optimal for you. You should never—just as with your own child—force anything. Instead, you should get to know your own body so well that you understand what it wants and what it needs, and adjust accordingly.
We often do this intuitively, but often maladaptively—which is why trends don't take off, yet the population remains metabolically sick. Maybe your muscles want some carbs, but you're stuffing yourself with white bread and pasta all day. That's why low carb might help at first, but mid-term your body—your muscles—are missing something. The same goes for veganism: At first, you were eating too much cured meat, but mid-term you're missing heme iron, carnitine, etc. from red meat. Well...
PS: What your body likes to burn most on any given day is a mix of many different tissue types. We've just picked out the biggest energy consumer as an example. Logically, many other variables feed into this...
