You don’t have to be an elite athlete or super vigilant about what you eat during your workouts. Even casual exercise can burn more calories than your body at rest. This means you may need to eat more to support your workouts as well as your recovery.
“In a culture where ‘eat less, exercise more is the norm, many people fear eating enough [to sustain their workouts],” states Zoe Schroder RDN. She’s a nutrition coach and certified strength-and-conditioning specialist and is based in Tucson, Arizona. Underfeeding can lead to a slow recovery and a loss of motivation.
Here are some reasons why it is important to get enough calories and when you should eat more to fuel your workouts.
Why does your body burn more calories during exercise than at rest?
Todd Buckingham, Ph.D. is an exercise physiologist and a member of the Mary Free Bed Sports Rehabilitation Performance Lab. He says that the body gets the energy it requires in the form of calories. Carbohydrates are broken down into glucose, glycogen, and fatty acids. “From there, these glucose and glycogen molecules are broken down further into a molecule known as adenosine triphosphate (ATP), which provides energy. (Protein is broken down into amino acids, which then break down to ATP. However, this process is less efficient and can’t be used for exercise.
This process is known as metabolism and it happens continuously in your body. Dr. Buckingham explains that ATP production is increased during exercise to support your muscles, which are doing more than usual, as well as to maintain your higher heart rate and breathing. You will burn more calories if you have more ATP.
How many calories do you burn during exercise?
The Centers for Disease Control and Prevention states that an average 154-pound person would burn 300 calories an hour while engaging in moderate-intensity activities like walking or casual cycling. After an hour of intense exercise, such as running or swimming, or circuit weight training, the same person will burn between 440 to 590 calories. To get a better idea of how many calories you’ve burned during an activity, download the Physical Activity Calorie Counter. This calculates your body weight, exercise type, and duration.
How many calories do you need to support your workouts?
To maintain your current body weight and to keep your energy up, you should eat approximately the same amount of calories each day as you burn. This happens naturally for most people, even those who aren’t athletes. Schroeder explains that your body’s hunger hormone, ghrelin increases in response to exercise. This is your body’s way to tell you to eat more.
This means that you don’t need to increase your calories if you do moderate-intensity exercises (which burn about 300 calories an hour) only a few times per week. A past study found that exercising at a high intensity (running, circuit training, or HIIT) can suppress your ghrelin. Schroeder warns that relying on hunger cues alone could lead to you being undernourished.