Part 1 | Part 2 | Part 3 | Part 4 | Part 5
In part one of this series on universal truths, I discussed how the Internet has given rise to a whole class of fitness pseudo-gurus who preach universal truths like they are gospel. Then in part two, I highlighted how mistakes made in interpreting the exercise science and diet literature have helped perpetuate the belief that universal truths even exist.
In one of those weird instances of karma, I was forwarded this interview, a critical look at inadequacies in the US food pyramid, seconds before I posted part two of this series. Talk about timing! I recommend you take a couple of minutes to watch this clip as it serves as a great lead-in to today’s discussion.
Although one corroborating viewpoint doesn’t prove anything, you can at least be comforted in knowing that the information I’m about to share with you isn’t just the inane rambling of a delusional blogger. Rather, my opinions are shared by others with strong backgrounds in nutritional biochemistry and physiology.
Today, we are going to look at one of the major reasons why universal truths are so universally ineffective: bio-individuality.
Bio-individuality is simply a term coined to reflect that different individuals have different nutrient needs. This concept is well represented by the simple phrase:
“One man’s food is another man’s poison”
In fact, I would go so far as to suggest that if your nutritionist, personal trainer, physiotherapist or doctor doesn’t ascribe to the belief that different physiologies require different interventions, you seriously need a new practionner.
Let’s look at why…
One Diet to Rule Them All…
For quite some time now, more enlightened nutrition practitioners have been moving away from endorsing the kind of “one size fits all” recommendation espoused by our food guides.
Now I appreciate that the food guide is designed to apply to the entire population; however, in trying to create a document that applies to all, we’ve wound up with a document that benefits very few.
It really doesn’t take much effort to show how patently absurd it is to suggest there is a “best diet” that everyone should follow. Even a simple survey of the native diets from various populations the world over, all of whom experience tremendous health (defined for my purposes as a general lack of chronic disease), paints a pretty clear picture.
Although there are numerous examples, I’ll limit the discussion to five distinct diets:
- Traditional Inuit (Canada)
- Traditional Masai (Kenya)
- Traditional Kohama (Japanese)
- Traditional Mediterranean (Coastal Greece)
- Traditional Tokelau (New Zealand)
Although industrialization and globalization have changed what these populations eat today, historically their diets would have consisted of:
- Inuit: High in seal meat, wild game and fish. Little to no vegetable matter or starches.
- Masai: High in meat, blood, milk, fat, honey, and tree bark.
- Japanese: High in rice, vegetable, fermented soy products, moderate amounts of fish.
- Mediterranean. High in olive oil, legumes, unrefined cereals, fruits, vegetables, moderate consumption of dairy products (mostly as cheese and yogurt), fish, and wine and low consumption of meat and meat products.
- Tokelau: high in coconut, fish and breadfruit (an extremely high-starch fruit).
By looking through these 5 examples, we see humans thriving on diets where over 50% of total calories come from saturated fats (Masai and Tokelau), others where over 70% of total energy comes from carbohydrates (Japanese), yet another still where next to no energy comes from carbohydrates (Inuit) and finally one that offers a semblance of balance between carbohydrate, fat and protein intake (Mediterranean).
Apart from all of these diets being low in added sugars and processed foods, there are no real commonalities from a macronutrient perspective. And yet individuals following these traditional diets are remarkably free of chronic health conditions*.
*In contrast to the typical snake oil salemen who want to push a single food or supplement as the miracle cure or secret to great health, it is far more logical to conclude that the secret to great health is to avoid eating crappy processed foods.
How is this possible?
Aren’t vegetables mandatory for great health? Don’t white carbohydrates make us fat? Doesn’t saturated fat cause heart disease?
Clearly, despite what you have been told, the answer to all these questions is: not necessarily.
If nothing else, evolutionary biology has taught us that humans are a remarkably adaptable species, one of the few that can thrive on a variety of foodstuffs. This is why some humans can be optimally healthy on a vegan diet, whereas others can eat nothing but meat and still have great health.
To date, no civilization has shown the ability to thrive on a “fast food” diet.
Of course, these are the extremes and I wouldn’t necessarily endorse either dietary approach as optimal for the majority of the population. However, it is readily apparent that people are able to thrive on either extremes so by now I hope you’ll agree with me how totally pointless it is to argue that one approach is inherently superior to another.
Frankly, the only nutrition question we really need to ask ourselves is: how should I eat in order to optimize my function.
Although this seems like a logical question to ask, you’d be amazed at how often I encounter individuals making the mistake of eating entirely the wrong foods.
For example, I don’t care how “healthy” you might think vegetarianism is, if you are chronically fatigued and storing tons of excess body fat while eating vegetarian, clearly it’s not the right type of diet for you.
Conversely, to all those individuals who brag that they never eat any vegetables but who walk around with a 30 lbs spare-tire sitting around their midsections or a lovely set of scars from a recent quadruple bypass surgery… guess what guys, your diets suck too.
Ok, so we’ve seen how silly it is to argue that there is a “one size fits all”, best diet. But how to begin determing the optimal diet for yourself?
Now this may come as a surprise but remarkably effective strategies have existed for many years.
Some Kind of Somatotype
In the 1940′s, psychologist William Sheldon proposed that human physiques be categorized according to somatotypes, which he named after the germ layers of embryonic development: ectoderm (forms the skin and nervous system), mesoderm (forms the heart, muscles and blood vessels) and endoderm (forms the digestive tract).
Of course, you can trace references to different types of constitution requiring different intakes all the way back to antiquity, but the somatotype classification is one of the better known systems.
In the context of body typing, these became known as:
- ectomorphs: typically tall and skinny.
- mesomorphs: typically broad shouldered and muscular.
- endomorphs: typically short and squat.
As the theory goes, each consitutional type is better adapted for a particular type of diet. Although I’m not a huge fan of classifying macronutrient needs based on percentages, a typical somatotype diet distinction might look something like:
- Ectomorph: 60% carbohydrate, 15% protein, 25% fat.
- Mesomorph: 40% carbohydrate, 30% protein, 30% fat.
- Endomorph: 25% carbohydrate, 35% protein, 40% fat.
Although these macronutrient breakdowns are somewhat crude, they do make some physiological sense.
Ectomorphs, typically have a fast metabolism and are not prone to storing body fat. Therefore, they have no problem metabolizing and using the large amounts of immediate energy provided by a diet high in starches and simple sugars. These individuals are often waif-like marathon runners or your friend who can, “eat an entire bag of chips and drink several cans of Coke each day” yet never gain a pound.
If you are someone who struggles to manage your weight, you probably hate these individuals and deservedly so 
Mesomorphs on the other hand, tend to have quite a bit of muscle and a more moderate metabolism. Mesomorphs tend to be able to gain both muscle and fat relatively easily, but can also lose fat with a modest investment in cleaning up their diets. Therefore, they tend to do better on a diet of mixed macronutrient composition (think the Mediterranean diet).
At the other end of the spectrum we have endomorphs, who tend to easily store fat and have extremely sluggish metabolisms (the obese and type II diabetics would fall into this category). Limiting access to simple sugars and starches in favour of greater amounts of protein and fat are dietary strategies that typically work well for classic endomorphs.
These poor chaps definitely drew the short straw when it comes to managing their body composition, but such is life. They have to be uber vigilent about their diets and will need to accept that their training volume will also need to be higher if they desire such aesthetic features as “washboard abs”.
The only real way to avoid this unfortunate lot in life is making sure you do a better job of picking your parents.
Piece of Cake?
So problem solved, right? Divide all of humanity based on how they are built and start doling out the diet advice?
If only it were so easy.
Very few inviduals are pure examples of these classes so we wind up labelling a number of individuals as tweeners (meso-endos, ecto-meso). But even more importantly, we have clear examples of when the somatotype classification just doesn’t work… a theme I’ll address in my next installment in this series!
Till next time, train hard and eat clean!
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