Should You Be Exercising for Your Body Type?

Are some bodies better suited toward certain eating and workout plans than others? It's an enticing question to ponder, especially if you've long struggled with getting the fitness or weight-loss results you want.

The idea of three different body types, known as somatype theory, has been around since the 1940s. Back then, experts believed that every body fit neatly into one of three categories based on characteristics like body fat and muscle. And that each type was basically genetically determined to only ever look a certain way that could never be changed. (The theory also stipulated that certain body types were prone to certain personality traits…which is clearly, uh, ridiculous.)

Today, the idea that your body is preprogrammed to have a certain look or shape that can never be changed doesn't hold much ground, according to the National Academy of Sports Medicine (NASM).

But the question remains: Can eating or exercising a certain way help you achieve a drastically different weight or shape?

Turns out, the answer is both sort of complicated and super simple. Here's what the experts have to say.

According to somatype theory, bodies are endomorphs, ectomorphs or mesomorphs. These three types were thought to determine how a person looked and how easily they gained or lost fat or muscle. Let's take a quick look:

1. ​Endomorphs​ naturally carry more fat, particularly around the hips and thighs. They have a larger bone structure and tend to gain weight relatively easily, but aren't necessarily overweight.
2. ​Mesomorphs​ have a medium bone structure. They have an easy time losing or gaining muscle, and as a result, have an athletic build and a more proportional shape.
3. ​Ectomorphs​ tend to have a smaller bone structure and more narrow shoulders and hips. They have a harder time putting on fat or muscle.

These days, experts still agree that bodies tend to lean more toward one type or another. Part of the reason we look the way we do — and why we look different from one another — has to do with things like musculature, body fat levels and bone structure, according to experts at the University of Houston.

But most people don't fit neatly into one category. You might have smaller, ectomorph-like arms and shoulders and wider, endomorph-like hips and thighs, for instance. And your body's shape and structure is far from static — it can shift over the course of your lifetime, the NASM says.

Genetics certainly play a part in determining your body's basic frame, along with how easily your body gains or loses fat or muscle. But your DNA definitely isn't your fate, experts say.

"Genetics plays a large role in determining our height, skeletal structure, composition of slow-to-fast twitch muscle fibers, our insulin health and where we store body fat," explains K. Aleisha Fetters, CSCS, personal trainer and author of ​Fitness Hacks for Over 50​. "But genetics just sets the stage. How the play goes is determined by lifestyle factors."

In other words, what you eat and how much you move has a major effect on how much fat or muscle you carry. And as a result, your proportions of fat and muscle tissue have a major impact on your body's shape.

That's not to say that the same diet and exercise plan will give every person the same result, or that we should all be eating and working out the exact same way in the first place.

"I don't put much stock in somatype theory when it comes to nutrition recommendations for clients," sports dietitian Kelly Jones, RD, CSSD, tells LIVESTRONG.com. "There may be some considerations for nutrient goals and timing of food intake as it relates to their goals, but trial and error is always important to account for factors outside of their body type, including their actual fitness level, training program, gut health, food preferences and history of disordered eating."

Your body's basic shape also doesn't determine your weight. A person's somatype can only be guessed based on their body mass index (BMI) roughly half the time, according to findings published in ​The Social Science Journal.​ What's more, any of the three basic body types can be prone to obesity, concluded a study in ​Reviews on Environmental Health​.

"When people put effort into building habits that will serve their energy levels, muscle recovery and overall health for a lifetime, their weight eventually reaches the most appropriate place for them as an individual."

You'll never be able to make yourself tall if you're short or short if you're tall. You'll never be able to make your body store fat in a different spot or change your natural tendency for putting on muscle. But that doesn't mean you can't achieve your fitness goals and become the healthiest version of yourself.

"The ultimate goal should be to have the health you deserve to best enjoy your life," Fetters says.

The first step toward making that happen is to determine what you want from your body. Working with a certified personal trainer or registered dietitian can help you clarify your goals —and put together a plan for achieving them.

"The first step in creating an exercise program is a 'needs analysis.' What do you need for your best health and function?" says Fetters.

If you carry more fat around your middle, for instance, focusing more on strength training than cardio can help reduce the accumulation of age-related abdominal fat, research published February 2015 in ​Obesity​ shows. If you're after a more athletic upper body, hone in on strength moves that can build arm and shoulder strength, Fetters suggests.

As for diet? Unless you're an elite athlete with very specific goals, you'll reap big benefits by sticking with simple, healthy eating principles long-term — like eating plenty of fruits, vegetables, whole grains and lean proteins, not overdoing it with sugary treats and keeping your portions in check.

"When people put effort into building habits that will serve their energy levels, muscle recovery and overall health for a lifetime, their weight eventually reaches the most appropriate place for them as an individual," Jones says.

On the other hand? If it seems like you can't reach or maintain a certain size unless you stick rigidly to a very intense eating or exercise program, you may need to rethink your expectations. For instance, "if someone genetically prone to be an endomorph is constantly dieting and overexercising to try to achieve the look of a natural ectomorph, they may be living in a body size not appropriate for them in terms of physical and mental performance," says Jones.

In other words: Listen to what your body is truly trying to tell you, instead of trying to force it to fit a shape that might not be right for you.

"Your body is more than a body type. Every body is unique, individual and it deserves to be treated that way," Fetters says. "By fully evaluating your family history, personal history, lifestyle, likes, dislikes and so much more, you can zero in on what works best for you both as a body and a whole person."