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If you’ve ever heard someone talking about “macros,” they’re talking about three major nutrients: protein, fat, and carbohydrates.

Bodybuilders and fitness experts pay close attention to the macronutrient profile of the foods they eat to yield certain results—increased protein for muscle development and reduced carbohydrates for fat loss are some common examples of dietary targets.

By changing one’s macronutrient balance (i.e. a person on a high-fat diet gets most of his or her calories from overt fats, or foods rich in fats such as nuts and avocados), you can fuel your body with foods that will get you one step closer to your specific goals. Depending on whether your body composition goals are to gain muscle, lose weight, etc., you may give preference to one macro over the others.

Out of the three macros, one is often considered the least popular—carbohydrates or “carbs.” This is because comfort foods like pasta, bread, and cereal are high in carbs, and they’re linked to gaining weight. However, fruits and vegetables are also forms of carbs, and even at face value, you can see that based on this, not all carbs are created equal.

Do carbohydrates and body composition go hand in hand? Consuming a lot of carb-rich foods doesn’t automatically mean you’re going to gain weight. It all depends on the type you’re eating. However, cutting carbs does not necessarily mean that you will lose fat either.

People have long adopted high-protein diets to preserve lean body mass and high-fat, low-carb diets for weight loss, but high-carb diets are on the rise to achieve similar body composition results.

Different Types of Carbohydrates

There’s a stark difference between cookies and quinoa, yet both are classified as carbohydrates. The same thing goes for white bread and potatoes—both are carbs, but they’re vastly different in terms of nutritional content and overall effect on the body.

These different types of carbs have names: the type with a less complex structure is called a simple carbohydrate, including glucose, sucrose (table sugar), and fructose (from fruits) but starchy foods (potatoes, rice, etc.) and unprocessed plant-based foods are called complex carbohydrates. The next question is whether one is automatically better- the answer would appear to be complex carbs (as we’ll explain shortly) but the simple answer is no because even complex carbohydrates can be processed into less healthy versions, known as refined carbohydrates.

Carbs are often categorized as  “good carbs” or “bad carbs” but it isn’t that simple. The important thing to know about carbs is how they’re processed by the body. This helps us to understand how they affect body composition differently so that we can properly use carbohydrates to help us meet our goals.

Simple Carbohydrates

White flour and table sugar are examples of simple carbs. You might not recognize a simple carb when you see one, but if you’re looking at simple carbs on a molecular level, it is clear- simple carbs are made up of only 1 or 2 sugar molecules (while complex carbs have 3+ molecules bound together, hence the name complex).

Now the sugar in fruit isn’t quite the same as table sugar, but both fruit and white sugar are examples of simple carbs. While most simple carbs are what get called  “bad carbs”, they can actually provide significant benefits. Some simple carbs, like fruit, are packed with vitamins and minerals, providing you with high nutrient content. However, it is important to keep in mind that fruits are a bit of an exception in the simple carbohydrate category.

Consuming simple carbs gives you a readily available, quick source of energy. This is why major athletes sometimes consume candy right before a game, match, training session, or other performance events they want a rush of energy to power them through their physical endurance.

Simple carbs spike blood sugar levels, which can be dangerous and is a no-go for diabetics if intake is not monitored properly. The reason for this is this spike in blood sugar helps feed the body with glucose but will also cause the body to crash once this source of energy is used and glucose levels get low.

While a burst of energy may seem tempting, simple carbs have their drawbacks:

  • Simple carbs are generally low in nutritional value. Despite being high in carbohydrates, they’re low in essential vitamins and minerals. It is important to check the nutrition facts when choosing simple carbs.
  • When you consume simple carbs, you don’t stay full for long because they’re quickly digested. This can lead to binge eating because simple carbs aren’t satiating.
  • The consumption of simple carbs is also linked to serious health problems, including increased risk of coronary heart disease and a higher risk of type 2 diabetes.
  • Simple carbs can also be high in calories, which is not ideal for weight loss.

Intake of simple carbs, with the exception of fruit, should be limited, as they can hinder your body composition goals and lead to serious health problems.

Refined Carbohydrates

Refined carbohydrates fall under the umbrella of simple carbohydrates in that they may be less beneficial to overall health. By processing carbs, you change their molecular structure and get refined carbs, which include chips, white bread, muffins, donuts, etc. By changing their structure these foods last longer, which makes them easier to mass produce and sell (think fast food).

The sugar in refined carbs is linked to chronic diseases and high body weight, including:

It’s easy to fall into the routine of having donuts for breakfast, chips at lunch, and white bread at dinner, but refined carbs like these are giving all carbohydrates a bad name because of their effects on the body.

Complex Carbohydrates

On the other end of the carb spectrum lies complex carbohydrates. Unlike simple carbs, where the molecular structure consists of single sugar molecules, complex carbs are made of sugar molecules strung together on a chain. Whole grains, legumes, vegetables, and other whole and unprocessed plant-based foods are examples of complex carbs.

Complex carbs are broken down into starch and fiber, which are each processed by the body in a unique way.

The digestion process actually starts in your mouth: saliva mixes with the complex carbs, engulfs them, and a digestive enzyme called amylase turns them into a type of simple carb called maltose, which can form either in the mouth or once it reaches the small intestine. The maltose continues through the digestive tract until digestive enzymes turn it into glucose, which is then absorbed into the bloodstream.

From there, the complex carbs are processed similarly to simple carbs—as in they’re converted to a simple form to be used for energy—but this process is significantly slower. The slow increase in blood sugar level triggers the pancreas to produce a hormone called insulin, so the sugar can be stored or used as a source of energy.

The fiber in complex carbs isn’t broken down into glucose molecules, however. Fiber stays intact as it travels through the digestive system, but the two types of fiber have different roles: soluble fiber attracts water and allows the intestines to absorb nutrients, and insoluble fiber speeds up digestion. Both are necessary for a healthy digestive tract.

The way that complex carbohydrates are processed contributes to the main benefits of consuming complex carbs:

  • Complex carbs are digested slowly, giving you a feeling of satiety, allowing you to feel fuller for longer.
  • The slow digestion also sustains energy, instead of spiking and crashing like simple sugars. Complex carbs encourage steady energy levels.
  • The starch content in complex carbs are nutrient-dense, which means they’re full of vitamins and minerals.
  • Complex carbs are also high in fiber, which promotes healthy digestion and absorption of the nutrients.

You don’t have to be scared of all carbs when it comes to body composition. Simple and refined carbs should be limited, but complex carbohydrates are nutrient-dense and beneficial to the body.

Low-Carb vs. High Complex Carb Diets for Weight Loss

Understanding what we know now about the types of carbs and how they are utilized in the body, it is clear that there are a lot of complexities to planning your carbohydrate intake.

When it comes to diets that are best for losing weight, your mind may automatically jump to low-carb diets. For decades, low-carb diets like Atkins, paleo, and keto diets have been at the forefront of weight loss regimens.

Low-carb diets are effective for quick weight loss, but are they sustainable for long-term weight loss? The safety and effectiveness of low-carb diets have come into question, especially as high complex carb diets like vegetarianism, veganism, and the Mediterranean diet become more popular.

Weight Loss on a Low-Carb Diet

Because carbs are restricted on these diets, the body is forced to burn fat as a source of energy, so the weight loss can be driven by a loss of fat mass.

While low-carb diets are beneficial for weight loss purposes, lower carb diets aren’t encouraged for long-term use and are often associated with serious health complications.

Ultimately, more data is needed to recommend the long-term safety and health benefits of low-carb diets.

In regards to low-carb diets and body composition, low-carb consumption has a direct connection to muscle mass. Glycogen stores account for the primary energy source that muscle groups use to provide energy. When carbs are reduced, muscle glycogen concentration is also reduced, decreasing energy stores. This is also why bodybuilders tend to avoid low-carb diets as they can hinder their ability to maximize their workouts.

Weight Loss on a High Complex Carb Diet

The Mediterranean diet has long been accredited for effective weight loss results, and now other high complex carb diets, such as whole food plant-based diets, are gaining traction for efficient weight loss. The key is getting your carbs from complex carbohydrates in their whole food form and reduce intake of simple sugars or refined carbs.

A diet with 40-65% of calories coming from carbohydrates is considered normal, so if you’re consuming the Standard American Diet, you might be consuming more than half your calories without realizing it.

High-carb diets are associated with a naturally lower intake of calories, which is crucial for weight loss. A moderate consumption of carbohydrates (47-64%) has been related to a lesser likelihood of being overweight or obese in healthy adults.

Maintaining a calorie deficit is easy on a high complex carb diet because whole plant-based foods are generally high in volume yet lower in calories, allowing you to consume large yet low-calorie portions. Complex carbs like potatoes, legumes, and grains don’t spike your blood sugar like simple carbs, so you won’t experience the crash and cravings as with other carbs.

Weight loss on a high complex carb diet isn’t as dramatic as it is on a low-carb diet. However, gradual weight loss is generally thought to be healthier and more sustainable. Additionally, slower weight loss means a greater likelihood that the weight lost will come from fat instead of muscle mass.

Contrary to popular belief, carbohydrates can be weight loss powerhouses if the right types are consumed. While structuring a diet truly requires guidance from a professional, it is likely that they will recommend a diet that promotes better health:

Not only is weight loss possible on a high complex carb diet, but carbohydrates are necessary for sustainable weight loss. When it comes to body composition, complex carbs make it easy to decrease calories while having the energy to burn more calories through exercise. Plus, diets high in complex carbs are sustainable long-term and have many proven health benefits.

Carbohydrates Are Not the Enemy of Body Composition

USDA recommendations stipulate that 45-65% of calories should come from carbohydrates in all age groups. While this is a general recommendation and not a steadfast rule, having most of your carbohydrate calorie allotment come from complex carbs can be part of a healthy, well-rounded diet, especially for people whose body composition goals include weight loss.

The “bad” carbs that give all carbs a bad name have a poor reputation because they’re typically highly processed and have added sugars and flours. Simple and refined carbs aren’t good for weight loss and they aren’t health-promoting foods, but complex carbs shouldn’t be brought down with them. When the right kind are consumed in the right quantities, you can promote your overall health and a healthy body composition.

Maintain a Balanced Diet

Opting for a diet that’s higher or lower in one macronutrient may yield the body composition results you want, but maintaining a balanced diet is important in any restriction diet. Even in low-carb diets, you still consume some forms of carbohydrates, so make sure they’re complex. In high-carb diets, stick to starchy carbs and low-calorie, plant-based carbohydrates so unhealthy weight gain isn’t an issue.

So are carbs really bad for body composition? It depends on the type you’re consuming. Weight loss on a high-carb diet of sweets, chips, and white bread isn’t nearly as plausible as weight loss on a high complex carb diet of whole grains, legumes, and starchy vegetables. When you’re getting the right kind of carbs, changing your body composition is possible. This is because complex carbs boost your energy for exercise and keep you fuller for longer.

So move over, simple carbs, because complex carbohydrates are here to set the record straight.


Lacey Bourassa is a health and wellness writer in Southern California. Her areas of expertise include weight loss, nutrition, and skin health. She attributes her passion for healthy living to her plant-based diet. You can find out more about Lacey at

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