Proteins, Carbs, & Fats: How They Affect Your Performance


January 18, 2018


What may be considered the best tasting macronutrient can sometimes be misunderstood. We’re talking about carbohydrates.

Carbohydrates are a fundamental macronutrient. Each molecule of a carbohydrate contains three elements: carbon, hydrogen, and oxygen, and are classified into sugars, starches, and fibers depending on their chemical makeup and digestive characteristics.

Simple Sugars (simple carbs)

Simple carbohydrates, or simple sugars, contain one or two sugar molecules and are quickly digested and absorbed by the body. They are generally found in fruits and processed sweets like cookies and cakes. Processed sweets are mostly filled with refined, added sugars that are low in nutritional value and can quickly affect blood sugar. When these types of sugars are consumed, the body experiences a spike in blood sugar and as a consequence, a rise in insulin production. Insulin is a hormone that assists glucose in entering the body’s cells to be used for energy. When too much glucose enters the body, insulin helps store energy in the liver to be used later.

Complex Starches and Fibers]


Complex carbohydrates, or polysaccharides, are generally digested and absorbed slower than simple carbohydrates due to their larger chemical structure. Slow absorption of complex carbohydrates keeps insulin secretion steady, which sustains blood sugar levels compared to simple carbohydrates that ignite a quick insulin response. Complex carbohydrates are found in whole grains including wheat, barley, oats, green, leafy greens, starchy vegetables like carrots, potatoes, and pumpkin, as well as beans, lentils, and peas.


Fiber refers to the nutrients in foods that are indigestible. As fiber passes through the digestive system, it remains mostly intact, only broken down into soluble and insoluble fibers. Soluble fiber has the ability to bind with water and create a gel-like byproduct in the digestive tract. It can also bind to and help the body excrete cholesterol. In contrast to soluble fiber, insoluble fiber does not bind with water and remains in its whole form. Insoluble fiber plays a large role in bowel health, as it bulks stools and promotes regularity. Sources of insoluble fiber include beans, vegetables, and most whole grains.

Why Low-Carb Diets Hurt Performance

When training at an intense level, or above approximately 70 percent of your VO2 Max (a measure of the peak amount of oxygen the body can take in and use per minute), about 80 percent of your energy comes from glucose and glycogen. When the brain is deprived of carbohydrates, it changes to a self-protective mode and restricts the number of carbohydrates the muscles can use to make sure it receives enough energy to maintain function. This can result in low energy and decreased performance during exercise.

How to Fuel Your Workouts with Carbs

The amount of carbohydrates needed depends on the intensity of exercise. A light jog may not require a large intake of carbohydrates to fuel, whereas a long-distance run, an extensive weight lifting set or a HIIT session may need a bit more. That being said, not all carbs are created equally. It is recommended to consume carbohydrates with a low glycemic index (GI) throughout the day to obtain sustained energy, rather than foods with a high GI that can cause blood sugar spikes. Choose carbohydrates from whole food sources like fruits, non-starchy vegetables, and whole grains. Foods should be rich in fiber and ideally paired with lean protein and healthy fats.metabolic testing for weightloss goals

90 Minutes Before Your Workout

About 90 minutes before an intense workout, it’s smart to fuel up with a meal that contains complex carbs, proteins, and fat, or follow specific macro recommendations prescribed by a nutrition coach.

Only Have 30 Minutes before a Workout?

When a workout is on the horizon within 30 minutes, it is acceptable to fuel up with carbohydrates such as white bread, pretzels, white potatoes or bagels — yes, the refined carbs that are typically recommended to avoid. Choose a carbohydrate with a high GI that will raise blood sugar quickly and pump energy from the stomach into the bloodstream for muscles to use.

What to Eat After a Workout 

The body also needs carbohydrates post-exercise, ideally paired with protein. Carbohydrates help the body build muscle and restock glycogen stores to keep energy levels up for the remainder of the day. Seek out low-fat chocolate milk or a protein shake, then plan for a non-starchy, fiber-rich meal within 1-2 hours after a workout.


Like carbohydrates and fat, protein is a macronutrient the body needs in relatively large amounts to grow, develop, and function properly. In general, protein is perhaps the most important macronutrient to consume due to their role in the body: organs, tissues, muscles, and hormones are all made from proteins. When proteins are digested in the body, they are broken up into amino acids, which are the building blocks of tissues the body. Unlike carbohydrates and fat, the body does not store protein, meaning it has no reservoir to draw from when running low, so protein must be a part of an every-day diet for the body to maintain proper function. Protein comes from a variety of sources, including meat, milk, fish, soy, and eggs, as well as beans, legumes, and nuts.

Reasons to eat more protein:

Appetite and Hunger 

Out of all three macronutrients (fats, carbs, and protein), protein is by far the most filling relative to the volume of food consumed. This is due to the effect protein has on the hunger hormone, ghrelin. When protein is consumed, the level of ghrelin in the body decreases. This effect can be powerful. In one study, increasing protein from 15% to 30% of calories consumed made overweight women ate 441 fewer calories each day, even without intentionally restricting calories. If losing weight or belly fat is a goal, consider replacing some of the carbohydrates and fats in your diet with protein.

Muscle Mass and Strength

Protein helps form and grow muscle fibers. Therefore, it seems logical that eating more protein helps build muscle in the body. If an individual is physically active through lifting weights, they must ensure protein intake is high to build muscle volume and strength. Protein also helps prevent muscle loss when the body is in a “catabolic” (breaking down) state or during weight loss.

Bone Health

Most long-term studies suggest protein, including animal protein, has major benefits for bone health. People who eat more protein tend to maintain bone mass better as they age and tend to have a lower risk of developing osteoporosis and fracturing bones. This is especially significant in women after menopause, as they are at a high risk of osteoporosis. To reduce risk, incorporate plenty of protein in the diet and stay active throughout life.


A food craving is different from normal hunger. Rather than the body needing energy or nutrients, the brain needs to feel rewarded. Unfortunately, cravings can be incredibly hard to control. The best way to overcome a craving is to prevent them from occurring in the first place by – you guessed it — increasing protein intake. One study suggested that overweight men who increased protein to 25% of their daily caloric intake reduced cravings by 60% and reduced their desire to snack at night by one half.

Metabolism and Fat Burning

Protein intake has been shown to significantly boost metabolism and increase calorie burn to upwards of 80 to 100 or more each day. One study on protein intake during overfeeding found that participants consuming a high amount of protein burned 260 more calories per day than a low-protein group. This is equivalent to an hour of moderately intense exercise per day.

Weight Loss and Long-term Weight Maintenance 

When it comes to losing weight, protein is the most effective of the macronutrients. Along with reducing cravings, protein boosts metabolism and burns more calories because it takes more energy to digest. It is not surprising that an increase in protein intake leads to almost automatic weight loss. However, losing weight is only the beginning: maintaining weight loss is a much bigger challenge for most. Luckily, even a modest increase in protein intake has been shown to help with weight loss maintenance.

How much protein you should eat daily

Each person requires a different amount of protein based on the body’s needs. Body weight, gender, age, and level of activity all determine the ideal amount of protein needed. For instance, athletes require more protein than the average person who may not be exercising as intensely each day. Regardless, there are general guidelines that serve as a recommendation for daily protein intake based on body composition. To determine this, it is helpful to take into consideration the amount of lean mass on the body, which can accurately be measured by CompID Scan. For every 1 pound of lean mass, 0.8-1.6 grams of protein should be consumed each day. For example, an individual with 120 pounds of lean mass should consume between 96 and 192 grams of protein. However, these calculations can vary based on activity, goals and age. Overall, it is recommended to consume 30 percent of calories from high-quality protein per meal.

To further optimize performance, consume half a serving of protein 30 minutes before a workout and 30 minutes after – a total of 10 to 20 grams per serving of protein is ideal. Adding a carbohydrate with protein can help raise insulin, which slows protein breakdown and speeds muscle growth post-workout. This avoids any stored protein from being used due to a readily available supply of carbohydrates.


Fats provide both available energy and a source of stored energy in the body. Stored fat can provide insulation for body temperature regulation through the development of adipose tissue. Fat is comprised of fatty acids that play a role in brain development, blood clotting and the management of inflammation. The body is unable to generate certain essential fatty acids so it relies on foods in the diet to provide them. Fat is the most powerful source of energy, with 9 calories of energy in every gram of fat—more than twice the energy proteins or carbohydrates provide. Because calories from carbohydrates are usually burned within the first 20 minutes of exercise, the body relies on fat stores to maintain energy.

Types of Fat

Fats can be divided into three categories: saturated fats, trans fats, and unsaturated fats. Saturated fats are usually found in animal products including meat, cheese and milk, and have been shown to increase LDL (bad) cholesterol in the body. Trans fats, which form when vegetable oil hardens, are found in fried foods, processed foods, spreads, and baked goods. When considering a healthy diet, saturated fats and trans fats should be consumed on a limited basis. Unsaturated fats, or “healthy fats,” are found in fish, nuts, olive oil, canola oil and some vegetable oils. This type of fat should be consumed on a moderate basis to support cellular function and HDL (good) cholesterol level maintenance.

Recommended Daily Intake of Fat

Fat is an important part of a healthy diet and should be consumed on a moderate basis – not too much and not too little. Eating too much fat can lead health problems like high cholesterol. Limiting daily fat intake to the recommended allowance helps ensure the body still receives its benefits without potential health problems. Fat intake should be between 25-35 percent of daily caloric intake, which translates to fewer than 78 grams of fat per day for a 2,000-calorie diet. It is important to choose healthy, unsaturated fats instead of saturated fats or trans fats.

When it comes to macronutrients, balance is the key. Analyzing your fitness and wellness goals is important to determine the right proportion of macronutrients needed in your diet. A well-balanced meal plan that includes all food groups will help create and sustain healthy habits that support long-term goals.

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