General Nutrition

Eating for Athletics: How to Know If You’re Under-Fueling & What to Do About It

November 14, 2023

Written by

Medically reviewed by Rita Faycurry, RD

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Key Points

  • Under-fueling during athletic training can impact performance and lead to health risks.
  • To optimize performance and recovery, it's essential to strategize your nutrition.
  • It's vital to consume adequate carbohydrates before, during, and after training to support energy levels and recovery.

Have you ever found yourself feeling unusually hungry mid-way through your training? Do you feel like you should have progressed further by now? Do you find yourself feeling sluggish, easily frustrated during exercise, or feel like it’s harder to recover from your workouts as the week progresses? If so, you might be under-fueling your body during training.

A common challenge faced by many athletes, given their rigorous workout routines and busy schedules, is getting their nutrition right for optimum performance. It's easy for nutrition to take a back seat amid such a balancing act, but fueling strategies can enhance your performance and aid recovery.

Let’s get into the impacts of under-fueling for athletic performance, as well as how you can properly eat to meet your athletic goals.

The physiology of under-fueling

When you experience hunger, your body enters a catabolic state, essentially breaking down body tissues for energy. Catabolism isn't conducive to training, especially when you're aiming for strength and speed gains. Instead, an anabolic (building) state is the goal, where your body can adapt best to training.

Under-fueled athletes often have inadequate muscle and liver glycogen stores, which are crucial energy sources during training. They are more prone to dehydration and struggle to recover fully between practices. During moderate to high-intensity practices, your body can typically absorb 30 to 60 grams of carbohydrates per hour, so it’s important to replenish these stores accordingly.

Women specifically struggle with under-fueling so categorically that there is a name for it: the Female Athlete Triad. The triad represents a group of health risks that result from chronic underfeeding while training: low energy availability (often linked with disordered eating), osteoporosis, and amenorrhea (lack of a menstrual cycle). This can result in irregular or nonexistent periods and/or imbalanced hormones, both of which contribute to bone density loss. Bone density is crucial for enduring and recovering from high-intensity athletic training.

Remember: proper fueling isn't just about meeting your energy needs during a workout. It also involves strategic recovery measures for both pre- and post-workout to ensure your body gets the fuel and replenishment it needs. This practice aids in a faster recovery process.

How to prioritize nutrition for your sport

If you’re accustomed to undereating, figuring out how to eat the right amount can be daunting and confusing. Here are some guidelines to follow:

  1. Honor your hunger cues. You may have grown used to ignoring hunger pangs – now is the time to reconnect with them. Try to eat something when you first sense hunger instead of waiting until it is unbearable. This will help train your response and improve your overall hunger signals.
  2. Don’t skip meals. Avoiding meals or snacks is a surefire way to continue underfeeding. If you don’t like breakfast or train very early, look for a quick-digesting meal that feels doable and gives you adequate energy.
  3. Listen to your body. Honoring what your body needs is a practice just like your sport. Pay attention to how you respond to different meals, meal timing, training, sleep, and other key signals. Chronic fatigue, soreness, anxiety, bad sleep, and hair loss all signal poor recovery, which may mean you need to eat more.
  4. Eat more carbs. Carbohydrates tend to be the first food people cut out in pursuit of weight loss. But they’re the main source of energy for all activity, so try to reintroduce them and see how you feel.

How to eat for optimal athletic performance

Before training: You can aim to have a bigger meal two to four hours before a workout or a smaller meal or snack an hour or two before. These meals should be low in fat, moderate in protein and fiber, and high in carbohydrates. You should test what foods and timing work best for you – everyone is different.

During training: You should aim for 30-60 grams of carbs per hour of training while maintaining adequate hydration. You can use both liquids and/or small, frequent bites of high-carbohydrate foods. If your workout isn’t longer than an hour, you likely don’t need to eat mid-session.

After training: Depending on the intensity of your workout, try to consume food with both carbs and protein within the first hour after exercise. It’s important to eat within an hour or two after a session to replenish your muscles and support recovery. Waiting too long may lead to unnecessary fatigue, poor recovery, and potential overeating.

Of course, everyone’s needs are different. It will take some time and testing to find the right balance for your individual requirements based on your sport and training schedule. Working with a registered dietitian can help you find the right approach to nail your nutrition and maximize your athletic performance. Fay Nutrition’s network of vetted, board-certified RDs can help connect you with a provider covered b your insurance to optimize your sports nutrition. Click here to get started.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.


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Written by

Rita Faycurry, RD

Medically Reviewed by Rita Faycurry, RD

Rita Faycurry, RD is a board-certified Registered Dietitian Nutritionist specializing in clinical nutrition for chronic conditions. Her approach to health is centered around the idea that the mind and body are intimately connected, and that true healing requires an evidence-based and integrative approach that addresses the root cause of disease. In her books and articles, Rita offers practical tips and insights on how to care for your body, mind, and spirit to achieve optimal health and wellness.