Posted on July 23, 2025 by Kate Halsall

For decades, fitness advice has often been filtered through the lens of somatotypes — the idea that people fall into one of three body types: ectomorph, mesomorph, or endomorph. You’ve probably seen the charts. You might’ve even been told you “can’t gain muscle because you’re an ectomorph” or that “you’ll always struggle with weight as an endomorph.” 

But here’s the truth: 

Body types don’t define your potential — and they were never designed for that in the first place.

Let’s separate the facts from the fiction. 

❌ Myth #1: Everyone fits neatly into one body type 

The original somatotype system was developed in the 1940s by psychologist William Sheldon — not a fitness coach or physiologist. His theory linked body shapes with personality traits (yes, really), not training or nutritional needs. 

Most people are a blend of somatotypes. You might have long limbs like an ectomorph but carry more muscle like a mesomorph. Body types aren’t fixed categories — they’re broad descriptors. 

Truth: You’re not an ectomorph or a mesomorph. You’re you — and your needs are unique. 

❌ Myth #2: Your body type determines what you can achieve 

Saying an ectomorph can’t build muscle or that endomorphs can’t get lean is like saying tall people can’t run fast. It’s simply not true. While genetics do influence things like limb length, fat storage patterns, and muscle fibre makeup, they don’t dictate your limits. 

Anyone can gain muscle with smart programming and nutrition. People who gain fat easily can still lose weight — it just requires a tailored approach. 

Truth: Genetics affect the starting point, not the finish line. 

❌ Myth #3: You need to train and eat according to your somatotype 

You’ll find plenty of outdated fitness advice recommending “ectomorph workouts” or “endomorph diets” — usually rigid plans that ignore personal preference, training history, or current lifestyle. 

What works is responding to how your body adapts: 

  • Is your recovery slow? Adjust volume and rest. 
  • Are you not gaining muscle? Look at calories, protein, sleep. 
  • Are you gaining fat too easily? Adjust intake and activity level. 

Truth: A personalised plan based on your real-life response will always beat a generic “body type” protocol. 

❌ Myth #4: Your body type can’t change 

People often think they’re “stuck” in a body type forever. But your physique can change drastically with training, diet, hormones, age, and even stress or sleep. 

An “ectomorph” at 18 might look and perform very differently after a few years of consistent strength training and eating for growth. 

Truth: You’re not locked into a body type — your body is adaptable. 

So… Should We Ditch Somatotypes Altogether? 

Not necessarily. They can be a starting point for understanding someone’s natural tendencies — just like tracking someone’s posture or movement patterns. 

But they should never be used as limits or a justification for poor results. Instead, focus on: 

  • Actual data (e.g. strength progress, measurements, performance) 
  • Recovery and energy levels 
  • Adherence to training and nutrition 
  • How someone feels physically and mentally 

That’s how real results happen — not from fitting into a body-type label.