Posted on

How Dietary Differences Affect Athletics

When it comes to athletic performance, nutrition is an increasingly important aspect. Many of us have heard the phrase “food is fuel,” and that’s how athletes need to look at dietary nutrition. During training, athletes need adequate energy to maintain a level of intensity, and the energy produced when our bodies break down food is how we sustain that intensity. However, not everyone has the same nutritional needs, and some even have nutritional restrictions.

Dietary Choices

While some people have to restrict the foods they eat for health reasons, others limit their eating habits by choice. Diets like pescatarian (only fish as a “meat” source), vegetarian (absolutely no meat), and vegan (an entirely plant-based diet with no animal by-products) are all restrictive diets that eliminate one or more food groups. And although proteins found in meat can be substituted for the most part, , it still can be challenging when it comes to an athlete’s need for protein.

Vegetarian and vegan athletes may be at risk for low energy, protein, and micronutrient intakes because of high intakes of low-energy–dense foods and the elimination of meat and dairy from the diet. It’s recommended that athletes with any of these restrictions work with a dietitian to be sure they’re meeting their bodies’ needs.

Other Diets

Beyond vegetarian or vegan, some people use dieting to reach a certain weight or physical appearance. Low-carb and low-fat diets are popular, but for athletes, special consideration needs to be taken before starting any kind of restrictive eating as it could impact performance. In fact, one study found that eating a low-carb diet for 7 days significantly impacted both physical and mental performance. Strength and endurance decreased substantially, and tension, anger, mental fatigue, and confusion increased considerably.

Fat has been a controversial topic in terms of dieting. Most people think they need to cut out fat altogether in order to achieve a certain physical appearance, while the latest diet trend, ketogenic, encourages fat intake vs. carb intake. When it comes to athletic performance, neither restricting intake nor high-fat diets have a significant impact. Additionally, a statement from the American Dietetic Association explains:

“Fat is important in the diets of athletes as it provides energy, fat-soluble vitamins, and essential fatty acids.”


Another type of dieting fad, intermittent fasting has become a popular way to lose or maintain weight and/or maximize the metabolic system. However, some religions call for fasting, as well. This can put an incredible strain on athletes, as they are not getting enough food to fuel their intense gameplay. It’s important for these athletes to consult a nutritionist or dietitian in order to maintain their health and performance during periods of fasting.


Diabetes is a complicated health concern which involves the management of blood sugar levels with stringent food restriction and/or insulin injections. People with diabetes need to take special care when eating so as not to disrupt their blood sugar, and sometimes this requires a low-carb diet. For athletes, this poses a problem. Carbohydrates are important to maintain blood-sugar levels during activity and replace muscle glycogen. Additionally, sugary sports drinks are usually a must-avoid for athletes with diabetes who want to maintain a certain glucose level.

Learn more about diabetes and athletics.


Another reason athletes may be limited by food is if they have allergies. Some of the most common food allergies include eggs, peanuts, and fish, and these restrictions require athletes to get creative in order to meet certain nutritional needs. For example, an allergy to dairy could reduce the intake of calcium, which could lead to health issues like osteoporosis. However, you can substitute the calcium found in milk and cheese with leafy greens like kale and spinach or fortified wheat products.


Supplements can also be used to help fill any dietary gap in nutrition. Many athletes use protein powders to increase their intake of protein and amino acids for muscle growth and recovery, but most nutritionists believe that protein needs can be met through diet. Additionally, it’s recommended that athletes who are eliminating certain foods utilize multi-vitamin/mineral supplements to fulfill any micronutrient deficiency, such as the calcium example above.

Supplementation for Visual Performance

While eye health is not often thought of as a piece of the performance puzzle, it’s an incredibly important aspect and can be improved through supplementation. Studies show that taking at least 20 mg of dietary zeaxanthin, a critical antioxidant for healthy vision, a day can improve contrast sensitivity, visual acuity, visual processing speed, and reaction time. However, athletes in general need to watch which supplements they take, as many are not certified to be used in a sports performance capacity.

EyePromise performance vitamins are all NSF Certified for Sport, meaning that the formulas are testing through third-party labs to ensure that what you see on the label is what you get in each and every dose, nothing missing and nothing extra (like banned NCAA substances). Each of these formulas have been designed to enhance visual function and improve game-time performance. Furthermore, our extensive product line offers nutritional solutions for athletes, people with diabetes, vegetarian or vegan diets, and even gluten-free needs.

Learn more about performance and nutrition or find out which EyePromise vitamin is right for your needs.