Unless you’re an elite athlete, there’s no need to be hypervigilant about how you fuel your workouts. But even occasional exercise burns more calories than your body would if you were at rest, which means you may need to eat more to support both your workouts and your recovery.

“In a culture that emphasizes ‘eating less, exercising more,’ many people are afraid to eat enough. [to support their workouts]says Zoë Schroder, RDN, nutrition coach and certified strength and conditioning specialist based in Tucson, Arizona. But ultimately, running out of fuel will undermine your goals and slow your recovery.

Here’s why getting enough calories is so important and how to know when you need more calories to fuel your exercise routine.

Why does your body burn more calories during exercise than when resting?

“Our bodies get the energy they need in the form of calories, primarily carbohydrates and fats,” says Todd Buckingham, PhD, exercise physiologist at the Mary Free Bed Sports Rehabilitation Performance Lab in Grand Rapids, Michigan. Carbohydrates break down into glucose and glycogen, while fats break down into fatty acids. “From there, these molecules of glucose, glycogen, and fatty acids further break down into a molecule called adenosine triphosphate (ATP), which provides energy.” (Protein breaks down into amino acids, which also break down into ATP, but this process is less efficient and not used to fuel exercise.)

This process, known as metabolism, happens constantly in your body, even when you are still, such as when you are sleeping in your bed or working at your desk. But during exercise, Dr. Buckingham explains, the rate of ATP production increases to support your muscles (which are working harder than usual), as well as to regulate your body temperature and maintain your heart rate and breathing. increased. The more ATP you produce, the more calories you burn.

How many calories do you burn during exercise?

According to the Centers for Disease Control and Prevention (CDC), an average 154-pound person will burn about 300 calories per hour during moderate-intensity exercise like walking, golfing, and occasional cycling. The same person would burn between 440 and 590 calories after one hour of vigorous exercise such as running, swimming or circuit training. For a more accurate estimate of the number of calories you burn during a certain activity, you can use a free physical activity calorie counter, which takes into account your body weight, type of exercise and duration .

How many calories do you need to sustain your workouts?

To maintain your current weight and maintain your energy level, you need to eat roughly the same number of calories you burn each day. For most people who aren’t elite athletes, this happens naturally, without you having to consciously add more food into your day. “Your hunger hormone, ghrelin, intensifies in response to increased physical activity, with your body telling you that you need to eat more,” Schroeder explains.

This means that if you’re only doing moderate-intensity exercise — which, remember, burns about 300 calories per hour — a few times a week, there’s probably no need to intentionally increase your calories. But if you train at a vigorous intensity (running, circuit training, HIIT), which burns more than 500 calories per hour, your ghrelin levels may actually be suppressed post-workout, according to a previous study. So relying solely on your hunger cues could leave you undernourished, Schroeder says.

“Too large a calorie deficit can lead to loss of muscle mass,” Buckingham says. That’s not a good thing, because muscle mass supports your health by not only allowing you to perform physical tasks, but also performing basic functions like pumping blood through your body and helping you breathe, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Plus, having muscle mass actually helps your body burn more calories overall, even at rest, according to a previous study.

If you’re trying to lose weight, a small calorie deficit is acceptable. The Academy of Nutrition and Dietetics (AND) recommends a calorie deficit of no more than 250 to 500 calories per day for active adults. If you notice over time that you’re losing weight and you don’t want it, you can try increasing your calorie intake by a few hundred calories a day, Buckingham says. One hundred calories equals about one medium banana or 1 tablespoon of peanut butter.

5 signs you need more calories to support your workout

Pay attention to these common signs that you need more calories to make sure you’re eating enough to support your workout routine:

1. Lasting pain

“If you notice you’re still sore long after a workout, that’s a sign of nutritional deficiency,” Schroeder says. A little pain is fine, but if it lasts for several days, you may need to increase your calorie intake, as proper fueling is key to muscle recovery.

2. Poor performance and fatigue

If you notice that you’re not able to go as hard, fast or heavy in your workouts as you used to, or if you’re constantly tired outside of your workouts, Buckingham says it could be a sign that you’re not. not eat enough.

3. Illness or injury

Buckingham also warns that not eating enough calories to support your workouts can lead to disease and injury because muscle repair and immune function depend on energy and nutrients from food.

4. Dizziness

Hypoglycemia occurs when you don’t have enough stored energy. Called hypoglycemia, low blood sugar can cause dizziness or lightheadedness, according to the Mayo Clinic. This is another sure sign that your body needs more calories than you take in.

5. Lost or irregular period

Over a long period of time, the combination of exercise and eating too few calories can lead to hypothalamic amenorrhea, a deficiency of the reproductive hormone estrogen. A review of the literature published in February 2019 in Reproductive Medicine Seminars explains that hypothalamic amenorrhea can lead to lost or irregular periods, as well as irreversible bone loss and an increased risk of cardiovascular disease. As this is a more serious symptom than others, it is best to discuss it with your doctor.

Tips for increasing your calorie intake

The good news is that increasing your calorie intake is relatively simple. Schroeder recommends adding one or two snacks between meals that contain a balance of protein, carbohydrates and fats. “Carbohydrates are your body’s primary fuel during exercise, so it’s important to replenish them afterwards,” Schroeder says. “Protein is essential for building and maintaining healthy muscle, and fat is important for vitamin absorption, hormonal function, and overall health.” Some easy snacks suggested by Schroeder are peanut butter and banana, fruit and yogurt, or hummus and crackers. Portion size will depend on both your goals and the number of calories you burn during a workout. If you’re aiming to eat 300 calories, you can get it with a medium banana and 2 tablespoons of peanut butter.

If snacking isn’t your thing, or if you need more calories than snacking can provide, Schroeder also recommends adding more healthy fats to your meals, as fats contain more than double the calories (9 calories per gram) compared to protein and carbohydrates (4 calories per gram), according to the Cleveland Clinic. “Things like avocado, olive oil, and peanut butter can boost calories without adding too much extra bulk,” she says. Ultimately, eat healthy, whole foods to feel energized during workouts and throughout the day.