Are you someone who even so much as sniffs a piece of cake and gains weight? Or maybe you’re the polar opposite, and just can’t add more size to your frame no matter how much food you throw down your pie hole.

How can two guys with similar diet and training approaches have such drastically different types of physiques?

There’s Something About Somatotypes

Maybe you’ve heard of somatotypes. Their origins first entered the public conscious when a psychologist and doctor by the name of William Herbert Sheldon developed his somatotyping system in the 1930s, and this is where ectomorphs (thin), mesomorphs (muscular and lean) and endomorphs (fat) came about. He actually based his work on what he believed to be psychological attributes tied to each physical appearance. However, today that notion has generally been dismissed as outdated by modern scientists.

man's torso

New research has shed light on the differences in metabolisms from one person to the next, substantiating the claim that body type variations do exist in the world today. Since the FTO gene was discovered – which links individuals to obesity – studies have been conducted to see what impact the gene has on those cursed with it.

Researchers at the Medical Research Council’s Epidemiology Unit in Cambridge examined data on genes, weight and the exercise habits of 220,000 adults from around the world. In sedentary people with the gene, odds of obesity were 30 percent higher than in those who did not have the gene, which was consistent with previous research.

A recent study in Sweden found a correlation between obesity and a person’s ability to make amylase (AMY1), an enzyme that helps break down starch (carbohydrates) in your mouth. The results showed those who have more AMY1 (the gene that correlates with the amount of amylase you have) had lower Body Mass Indexes (BMI) across the board, lending credence to the “carb intolerance” theory of weight gain.

lean male physique

But, there’s a caveat. Just because you’re “carb intolerant” or were born with the FTO gene, doesn’t mean you’re destined to fail in your fitness and health pursuits. In the Cambridge research, among those who exercised, the effect of the FTO gene on obesity was reduced by 27 percent.

While, in the case of carb digestion, if you feel you’re carb intolerant and lacking in amylase, a quick tip to level the playing field with those pesky high responders is to eat slower and improve the efficiencies of the amylase you do have.

Closing Thoughts

Whether the literal definitions of the three somatotypes exist or not, there are wide variations in body type, carb tolerance and exercise response from one person to the next. What one person can get away with diet wise, another simply cannot. That’s the reality.

And, yes, if your parents battle obesity, you of course run the risk of following in their footsteps through genetics and environment, but don’t compound the risk by living a sedentary lifestyle and eating junk all day.

The take home point is ultimately not to let your genetic limitations hold you back. You can improve what you consider a sub-par metabolism through diet and exercise. Don’t let mental barriers stop you from getting started.