Have you ever wondered why some people seem able to eat whatever they want without gaining weight while others only have to look at junk food for the scales to start spinning? Or why some exercisers build muscle easily while others train like maniacs but never seem to pack on any muscle mass?
There are several reasons why people respond the way they do to their food and workout, including genes, dominant muscle fiber type, insulin sensitivity, training experience, and underlying medical conditions.
Some also believe your somatotype or body type also may determine your ability to gain muscle or store fat.
In this article, we take a look at somatotyping and lift the lid on this fascinating and somewhat controversial subject.
Somatotyping was invented in the 1940s by American psychologist William Herbert Sheldon. Sheldon identified three main somatotypes – ectomorphs, mesomorphs, and endomorphs.
Ectomorphs are characterized by their slim builds, narrow shoulders, small joints, slender bones, and light musculature. Ectomorphs are often labeled as “hard gainers” as they don’t gain muscle easily. Endurance athletes are often ectomorphs.
Mesomorphs have broad shoulders and narrow waists and are naturally athletic and muscular. Often referred to as easy gainers, mesomorphs usually build muscle more quickly. They are well-suited to strength and power sports (1) but are not generally known for their endurance. Most top-ranked bodybuilders are thought to be mesomorphs.
Endomorphs tend to gain fat easily. And while they can usually gain muscle, they must be careful not to gain too much body fat. Many heavyweight weightlifters, strongman competitors, and wrestlers are endomorphs, i.e., they’re muscular but also carry a lot of body fat. As such, they often have a less aesthetically-pleasing shape than the classic “Greek god” mesomorph.
Somatotypes: Brain, Not Brawn
It’s often suggested that the different somatotypes should train differently and even follow different diets. While the concept of somatotyping does have some merit, the truth is it was never really meant to be used with exercisers and was, in fact, a way of classifying personality types.
Sheldon’s somatotypes were initially conceived to predict behavior based on appearance. For example, ectomorphs (the skinny ones) were more likely to suffer from a nervous and stressed disposition. In contrast, mesomorphs (the muscular ones) were more likely to be domineering and commanding.
Interestingly, endomorphs (the fat ones) were thought to be happier and jollier than the other somatotypes.
So, the aim of somatotyping was to connect the dots between physical and psychological traits. It had nothing to do with muscle-building, fat loss potential, or a person’s response to training.
However, these somatotypes have since become attached to exercise.
For example, many exercisers are quick to label themselves according to things like wrist size, hip width, muscle belly length, and other spurious physical characteristics that have little connection to true somatotypes.
Some people even follow workouts or diets based solely on their self-diagnosed somatotype. And while your genetics do dictate your ultimate physical shape, many people end up underachieving because they follow workouts designed for their body type and not their actual training goal.
The reasons that somatotyping may cause more problems than it cures include the following:
1) Somatotypes provide a convenient excuse
Many exercisers are very quick to blame their lack of progress on their somatotype when, in actuality, a lack of commitment or effort is the problem. Some even see it as a barrier to participation or a reason to not even start. For example:
“I can’t lose weight; I’m an endomorph.”
“I’ll never build big muscles; I’m an ectomorph.”
“I’m a mesomorph, so I’m no good at running.”
These people wrongly assume that being a mesomorph, endomorph, or ectomorph means that no amount of hard work will pay off. Such labeling can be limiting and even hurtful.
In reality, ectomorphs can gain muscle, endomorphs can lose fat, mesomorphs can succeed in endurance sports, and all three body types can become obese (2). It’s a case of nurture vs. nature, and you can always improve your chosen avenue of fitness and exercise if you apply yourself.
Personally, I’ve been a 154-pound triathlete and a 198-pound drug-free powerlifter – that’s some spread for a supposed ectomorph.
2) Pure somatotypes are very rare
Very few people can be considered to be 100% ectomorph, endomorph, or mesomorph. In fact, most people are a mix of all three. We’ve all seen the skinny guy with the fat belly (ectomorph/endomorph) or the person with powerful arms but slender legs (mesomorph/ectomorph), and the fat but muscular fellow (endomorph/mesomorph).
If the somatotypes are supposed to exercise and eat according to their body type, what should those who demonstrate different somatotype characteristics do?
What program should an ectomorph/mesomorph follow? What diet would be best for an endomorphic mesomorph? This sort of conundrum can lead to paralysis by analysis, detracting from what really matters – training hard and consistently.
Or, you could forget your supposed somatotype and just train and eat for your goal. Sure, some people are blessed with better genetics and will progress faster and to a higher level. But, if you put in the work, you can always improve your fitness and physique.
3) Unrealistic expectations
Having a particular body type does not guarantee that your body will respond favorably to a specific kind of training. For example, just because you think you’re a mesomorph and believe that all top bodybuilders are mesomorphs doesn’t mean you will get the same results if you follow the same workout.
So many other things can affect your progress, including muscle attachment sites, muscle belly lengths, the ratio of fast vs. slow twitch muscle fibers, mitochondrial and capillary density, pain threshold, dedication, drive, and your willingness to use performance-enhancing drugs…! It’s a long list.
Golden-era bodybuilder Frank Zane, a famous so-called ectomorph, amassed incredible muscle size despite being labeled as a hard gainer. He was certainly a different shape from the mesomorphic Arnold Schwarzenegger. Yet, he was equally impressive and won three Mr. Olympia titles. It’s a good job that Zane didn’t aim low simply because of his somatotype.
The same is true for ectomorphs, who are supposedly built for endurance. Yes, top marathon runners are very slender and light, but so are the club runners who finish two or more hours behind them. Your body type is no guarantee of success, and you cannot assume you’ll be good at something just because of your somatotype.
While there is nothing wrong with identifying your somatotype, it’s important to understand that it doesn’t have to affect your workouts or diet. The main thing to understand is that your body type can affect your rate of progress and your ultimate level of performance or development.
A true ectomorph may never build the massive muscles of a mesomorph but can still develop an impressive, muscular physique.
Similarly, an endomorph may tend to gain fat more easily or lose it more slowly, but that doesn’t mean they CAN’T get lean.
Mesomorphs can make great distance runners if they train appropriately, but their tendency to gain muscle means they’re often naturally bigger and heavier than other endurance athletes. This extra weight may be detrimental to their performance.
So, don’t get hung up on your somatotype. Your diet and training should reflect your goals and not your body type. Regardless of your somatotype, your body will adapt to the kind of training you do.
Hard work and consistency always pay off, regardless of whether you are a meso, endo, or ectomorph.
1 - Ryan-Stewart H, Faulkner J, Jobson S. The influence of somatotype on anaerobic performance. PLoS One. 2018 May 22;13(5):e0197761. doi: 10.1371/journal.pone.0197761. PMID: 29787610; PMCID: PMC5963773.
2 - Koleva M, Nacheva A, Boev M. Somatotype, nutrition, and obesity. Rev Environ Health. 2000 Oct-Dec;15(4):389-98. doi: 10.1515/REVEH.2000.15.4.389. PMID: 11199249.