Proper fueling when you’re training is about more than just eating when you’re hungry and stopping when you’re full, and it’s tough to get enough calories when you’re avoiding often-demonized calorically dense foods. While we’re thankfully undergoing a seismic cultural shift away from traditional diets and restrictive eating, subtler food rules like “don’t eat processed foods” or “limit carbs” persist among health-conscious people. These principles might seem innocuous, but the trouble with food rules is that they almost always decrease your caloric intake, and many active people have internalized ideas that make it tough to consume enough energy throughout the day. Limiting carbs might mean swapping bread for vegetables, and avoiding processed food could lead you to forgo on-the-go snacks or tasty desserts.
Kelly Jones, a Philadelphia-based certified sports dietitian who has consulted for USA Swimming and the Philadelphia Phillies, sees this often. “The majority of the clients that come to our practice, as well as athletes whose teams I consult for, are underfueling in some way,” she says. Jones explains that they’re not eating enough overall, not getting enough carbohydrates, or not eating the right nutrients at the right time. Below, two sports nutrition experts share the fueling mistakes that they often see athletes making, as well as how to avoid them.
Veggies Aren’t Always Best
Fruits and vegetables are key to a healthy overall diet, and athletes, like everyone else, should be aiming for five servings per day. But it’s possible to overdo it, particularly if you subscribe to clean eating, or the idea that whole foods are always best. “Athletes may eat a lot of high-volume ‘healthy’ foods, like squash, salads, and vegetables, which leave them feeling full even though they have not met their calorie needs,” says Anne Guzman, a sports nutritionist and researcher at Brock University in Ontario. Vegetables high in fiber and water fill you up, but they’re relatively low in calories and macronutrients, which means they don’t provide much energy. Take a look at your meals: are you mixing in an adequate serving of fats, carbs, and protein with your veggies? A kale salad with tomatoes, cucumbers, and sprouts is a good start, but try adding calorically dense toppings like nuts, cheese, chicken, avocado, and olive oil—and eat a slice of bread on the side.
Don’t Trust Your Gut
Even the non-diet approach, which prioritizes relying on hunger and fullness cues to tell you when and how much to eat, may not work for athletes without some modifications. “Those who eat based on stomach hunger can wind up with very low energy intake compared to what they’re burning,” Jones says.
This may be because, contrary to popular belief, exercise can actually decrease appetite. “Several factors can affect post-exercise appetite, including but not limited to hormones and blood redistribution during exercise,” Guzman says. A 2020 review published in the American Journal of Physiology-Endocrinology and Metabolism describes that the buildup of lactate in your blood during intense exercise is associated with lower levels of ghrelin, the hormone that makes you feel hungry. And a 2016 review in the journal Appetite explains that many other things may contribute to decreased appetite post-workout, including the effect that exercise has on the levels of insulin, glucose, and fat molecules in your bloodstream.
The amount of food you need depends on the length and duration of your workouts and your basal metabolic rate (BMR). The best way to figure out your energy needs is to work with a dietitian or estimate them using a calorie calculator that takes your activity level into account.
Stop Cutting Carbs
Carbs are the foundation of a healthy diet. The U.S. Department of Agriculture’s Dietary Guidelines recommend that carbs make up 45 percent to 65 percent of your total daily calories. But they’re even more important for athletes.
“Carbs are the most efficient and preferred energy source for exercising muscle,” Jones says. It’s important to eat them throughout the day, not just during or around workouts, because carbs get stored as glycogen to be used during exercise. When you run out of stored glycogen and there’s not enough glucose in your bloodstream, your body will start burning fat—which is OK but not optimal for high-intensity workouts—and may also start breaking down muscle for protein.
“To ensure the body isn’t tapping into muscle protein, which can impair recovery and adaptation to training sessions, eating adequate carbohydrates throughout the whole day is important,” Jones says. You should eat a pre-workout meal or snack that’s high in carbs, and if your workout is moderate or high intensity and lasts longer than an hour, eating at least 30 grams of carbs per hour (one banana, two slices of bread, or three or four energy chews) will improve performance and prevent muscle breakdown.
Don’t Fear Processed Foods
Even if you’re not dieting or trying to lose weight, you might still try to limit your intake of processed foods. That can be a good thing, to a point, as whole foods generally contain more nutrients. But there’s no need to eliminate processed foods completely. For one thing, processed carbohydrates are easier to digest because they lack fiber, which means that they’re generally a better choice before and during a workout. The carbs from a sports gel will enter your bloodstream and give you energy quickly, whereas the carbs in an apple will take longer to absorb. The apple’s high fiber content may also upset your stomach, particularly because exercise diverts blood away from your gastrointestinal tract and slows digestion.
Processed protein sources, like powders and bars, can also be helpful. “The recommended intake of protein for both female and male strength and endurance athletes is 1.2 to two grams per kilogram of body weight per day, ideally with meals spread throughout the day,” Guzman says, citing a 2016 paper published in the Journal of the Academy of Nutrition and Dietetics. For a 150-pound woman, that’s between 82 and 136 grams of protein per day, which can be hard to get from whole foods sources like nuts, cheese, or yogurt.
“Ideally, protein will be spread into moderate doses four to five times per day, rather than just having high doses post-workout and at dinner,” Jones adds.
Bottom Line: Break the Rules
Strict food rules are rarely sustainable, and even loose food rules like cutting back on processed foods or prioritizing vegetables can have unintended consequences when you’re an active person. “Healthy eating for an athlete is so different than for a non-athlete. Many athletes are not aware of how much higher their energy needs are,” Jones says.
If you’d like more guidance, check out the Athlete’s Plate, a tool that helps people visualize how much to eat based on training intensity. Ideally, this tool will help you give your body what it actually needs to perform and recover properly, instead of living by vague healthy eating maxims and arbitrary rules.