The Science of Excercise

Fitness Nutrition: What Science Says About Diet and Exercise

montage of eating and fitness images
(Image credit: Pindyurin Vasily, wavebreakmedia, Eldar Nurkovic, Marilyn Barbone/

No matter what your reason is for exercising — to strengthen your muscles, lose weight, increase your aerobic fitness or improve your mood — you likely want to get the most out of your workout.

But is there a particular way to eat to maximize that performance? To answer this question, Live Science talked to several experts about what the science says, and looked at some of the most definitive studies on nutrition and exercise.

It turns out there's no single best way to eat to be successful in your exercise goals. In fact, the vast majority of people who exercise do not need to eat anything special to support their exercise regimens, several experts said.  

"When someone tells you there is a specific magic diet or specific magic supplement, it's cause for suspicion," said Dr. Michael Joyner, an exercise physiologist at the Mayo Clinic in Rochester, Minnesota. "For the vast majority of people who are working out less than an hour a day, it doesn't make a whole lot of difference."

However, elite athletes or those engaging in hours of arduous workouts every day may need to tailor their nutritional approaches a bit more, studies suggest.

(Image credit: Purch Creative Ops)

As we'll detail below, exercisers simply need a well-rounded, healthy diet: high in whole foods, and low in processed foods and junk foods. People who go to yoga twice weekly, run for a few hours a week or hit the weight machines in the gym for an hour at a time typically do not need to eat specialized ratios of carbohydrates, proteins and fats.

Related: Does yoga help you lose weight?

Most importantly, the majority of people do not need to eat more calories to make up for energy expended in moderate workout routines — so a few spin classes are not an excuse to gorge on ice cream sundaes, Joyner said.

However, elite athletes, competitive athletes, and those who are doing very strenuous aerobic or resistance training may need to increase their carbohydrate and protein intake to maximize muscle recovery and energy levels during training, experts said. 

Ultimately, most people should take comfort in knowing that eating right for an exercise regimen is less about exhaustively calculating out certain proportions of protein, fat and other micronutrients in the diet, and more about eating healthy, whole foods, said Nancy Clark, a sports nutritionist and the author of the bestselling "Nancy Clark's Sports Nutrition Guidebook" (Human Kinetics, 2013). As long as about 85 percent of the diet is made up of nutritious, minimally processed foods, you are doing well, Clark said.

"You don't have to have a perfect diet to have an excellent diet. Some days, it's blueberries and some days it's blueberry pie," Clark told Live Science. "It's looking at the whole picture."

Workout Calorie Math

The average workout may burn calories, but not as many as most people think. Here are some simple guidelines to make sure you don't overeat and offset the benefits of that barre workout or 30-minute jog. [Full story: Here's How to Eat to Fuel a Workout]

Timing Meals and Exercise

Timing a meal to complement a workout can help people maximize the effects of exercise. We'll walk you through the best times to eat for your exercise regime. [Full story: Eating After Workouts: The Science of Timing Meals and Exercise]

Workout Supplements

The intensity of a workout determines whether a supplement can boost performance. Many supplements are often filled with mystery ingredients and may not have any documented effect. However, science has identified a few supplements that may be helpful to some athletes. [Full story: Workout Supplements: The Impact on Muscle Strength and Fatigue]

Exercise and Weight Loss

One of the most common reasons people take up an exercise routine is to lose weight, but eating for a weight loss exercise regimen is tricky. However, there are some simple nutritional guidelines that can help ensure you'll get the most out of your weight-loss workout. [Full story: Exercise and Weight Loss: The Science of Preserving Muscle Mass]

Nutrition for Extreme Workouts

Although most people don't need to overthink their eating plan when working out, elite athletes and those training for extreme endurance challenges may need to consider a few additional factors to get adequate nutrition. Elite athletes will need to plan the ratio of fat, protein and carbohydrate they eat, and will need to ensure they have the right number of calories to power grueling fitness challenges. [Full story: Extreme Workouts: The Nutritional Needs of Elite Athletes]

Original article on Live Science.

Tia Ghose
Managing Editor

Tia is the managing editor and was previously a senior writer for Live Science. Her work has appeared in Scientific American, and other outlets. She holds a master's degree in bioengineering from the University of Washington, a graduate certificate in science writing from UC Santa Cruz and a bachelor's degree in mechanical engineering from the University of Texas at Austin. Tia was part of a team at the Milwaukee Journal Sentinel that published the Empty Cradles series on preterm births, which won multiple awards, including the 2012 Casey Medal for Meritorious Journalism.