What Are Somatotypes? Does it Matter?

I’ve had a few requests to do a post on somatotypes. A somatotype is a genetic body type that is predicated on your stature as well as your muscle and fat mass. 

When asking me to write this piece, my friend and colleague Nicole Osinga told me that as an ectomorph, she processes carbs well. 

I’m an mesomorph, but I too process carbs extremely well. 

That got me wondering if there’s any truth at all to this somatotype stuff, because honestly in my 20 years of practice I’ve always ignored the concept that someone’s body type tells you anything definite about their exercise and diet requirements.

Where Did Somatotypes Originate?

Somatotypes were conceived in the 1940s by a psychologist named William Herbert Sheldon, who thought he could determine a person’s entire personality by how they looked. 

What are the Three Somatotypes? What Somatotype Are You?

Ectomorph: lean, with little fat and little muscle. These people are thought to have trouble gaining weight.

Endomorph: lots of fat and muscle, with a rounder body shape than ectomorphs. They are thought to gain weight easily.

Mesomorph: athletic and muscular, these individuals are thought to gain and lose weight easily.

Most people are a combination of these types though; it’s fairly rare to see a person who lands squarely in one of the above three. These include:

Ecto-endomorphs: the classic pear-shaped body with large hips and thighs and smaller upper bodies.

Endo-ectomorphs: apple-shaped, with more fat in their midsection and thin legs.

I know you’re busy thinking about which somatotype you are, but before you do that, for shits and giggles, here is the complete fucked up list of what Sheldon believed were the traits of each group:

Ectomorph: skinny, thin, slender, slim, lithe, lanky, neotenous, flat-chested, lightly muscled, weak, fragile, delicate, and usually tall; described as intelligent, contemplative, melancholic, industrious, effeminate, submissive, inferior, perfectionist, quirky, idiosyncratic, sensitive to pain, soft, gentle, loving, helpful, placatory, calm, peaceful, vulnerable, humble, self-deprecatory, socially awkward, solitary, secretive, concealing, self-conscious, introverted, shy, reserved, defensive, uncomfortable, tense, and anxious.

Endomorph: fat, round, heavy, usually short, and having difficulty losing weight; described as open, outgoing, sociable, amiable, friendly, affectionate, accepting, happy, pleased, satisfied, laid-back, easily complacent, lazy, ungenerous, selfish, greedy, well-endowed, and slow to react.

Mesomorph: hard, rugged, triangular, muscular, thick-skinned, and with good posture; described as athletic, eager, adventurous, willing to take risks, competitive, extroverted, aggressive, masculine, macho, authoritative, strong, assertive, direct, forthright, blustering, dominant, tough, strict, fortunate, vigorous, energetic, determined, courageous, and ambitious.

I mean, I guess I’m macho…ha ha! But endomorphs: fat, lazy, and slow to react? And ‘well-endowed’??! OMG.

Obviously, it’s pretty ridiculous and mildly offensive to believe that a person’s body type can predict who they are as a person. Eventually, Sheldon became known as a quack for even suggesting it (and probably for using photos of naked female university students without their knowledge, that too. )

Despite the fact that somatotypes weren’t created to predict how a person responds to exercise and food, plenty of outlets (many of them low quality) still publish ‘train for your body type’ or ‘how to eat when you’re an ectomorph’ types of articles, and I’m pretty sure people are still reading them. 

Can somatotype tell us if someone will build muscle easily? Or which diet they should eat? Do different somatotypes have different metabolic rates? 

Let’s crack this open and take a look.

Somatotypes and Exercise.

Look at anyone who has ever won a major marathon: they’re ectomorphs, long and lean. Football players? Classic endomorphs, with huge legs and trunks. Does that mean your somatotype limits the type of activity you do? 


While ectomorphs might find long-distance running easier and therefore may be more likely to do it, that doesn’t mean that the rest of us should limit ourselves to non-endurance sports. Humans are a lot more complex than how they’re shaped, and we all respond differently to certain types of exercise.

Dr. Nanci Guest, PhD, RD sport dietitian, strength & conditioning coach and genetics researcher, tells me that each person starts out with a general somatotype, but genetics, exercise frequency, volume and type play a huge role in how a person can override their body types. 

In short, there’s no evidence that proves that somatotype can predict how each individual will build muscle or skill in a certain sport. 


The predisposition of the different somatotypes to disease hasn’t been studied all that much, and the studies that exist are not all that great. 

This 2002 study found that endomorphs and mesomorphs had the highest incidence of liver disease and high blood pressure; this 2012 study found the same thing with type 2 diabetes. Other studies appear to find the same conclusions: the heavier somatotypes get the most diseases. Some of these studies were done on people who were already diabetic, and likely already overweight. Could these two body types – both of which apparently gain weight easily – be predisposed to disease as a result?

Predictably, ectomorphs, with their their slim build and low body fat percentage, seem to have the lowest risk of disease, at least according to the studies I found. 

That all being said, health isn’t the result of having a certain body type. It’s the result of different factors, including genetics, socioeconomic status, living conditions, education level, access to food, and many others. You can be an ectomorph with a shitty diet that results in a potbelly and the development of chronic disease. 

You’re born with the somatotype, but life can override it pretty darn effectively.


It seems to be incongruent that someone’s body shape would affect the way they process food, as much as horoscopes can predict that every single Sagittarius is a party animal. I’ve never really found anything that would lead me to believe that different diets work for different body types, which is fine by me: we don’t need any more anxiety about how and what we eat.

donut eating
My mesomorph body means that I have a lot of muscle, but contrary to some body type diet articles, I process carbs just fine, thank you


Still, some outlets try to make eating for your somatotype a thing, because clickbait.

I found this 2014 article published on the American Council for Exercise website. I’m going to have to take a hard pass (and a big head shake to ACE, which I thought had reputable information on their site). This and their other ‘eating for your body type’ posts doled out outdated information about how mesomorphs means they need a diet moderate in carbs and high in protein, and that ectomorphs should eat a diet that’s 50-60% carbs. While Dr. Guest does admit that ectomorphs are more likely to have a fast metabolism than the other somatotypes (so maybe there is some truth to that somatotype metabolism thing!), she says that basing diet entirely on body type doesn’t make sense when there’s genetics as well as environmental factors that also influence what we eat and how we metabolize food. 

So Do Somatotypes Matter?

As much as I tried, I couldn’t find any solid research about which diet is best for which somatotype. To me, this means that somatotype-derived diet recommendations must be 1. anecdotal 2. a wild guess 3. total BS 4. all of the above. 

One funny thing they all have in common though: every single ‘eat for your body type diet’ makes it seem like ectomorphs are always starving to death and endomorphs are always on a diet. Pffft.

Somatotypes exist in the sense that we have different body shapes, but basing workouts and diet entirely on them is probably a waste of your time. As Guest says, “it’s like categorizing people for diet by BMI or by blood type; the story is much more complicated than this.”