Dehydration increases the risk of gastrointestinal issues during exercise, with studies showing that athletes losing more than 2% of body weight in fluids are significantly more likely to experience nausea, cramping, and diarrhea. Underfueling can also have severe consequences, as I learned firsthand when I suffered a stress fracture 12 weeks out from my ultramarathon due to inadequate energy intake, which weakened my bones and impaired recovery.
Proper athlete nutrition isn’t just about eating healthy; it’s about strategic fueling to prevent issues like GI distress or injuries while maximizing performance. Whether you’re aiming to build muscle or compete in endurance events, nutritional demands are specific and unforgiving. Muscle growth requires consistent resistance training paired with a caloric surplus over weeks, while endurance athletes need to carefully time carbohydrate intake, targeting 60-90g per hour during intense activity. For activities lasting over two hours, I personally consume 80-90g of carbohydrates per hour to sustain energy levels and prevent bonking.
When developing an effective athlete nutrition plan, we must consider factors like training intensity, environmental conditions, and fat-free mass. Balancing energy intake with output is crucial; insufficient energy relative to expenditure risks relative energy deficiency in sports (RED-S), which can lead to injuries like my stress fracture.
In this article, we’ll break down how to fuel your body for optimal performance, whether you’re building lean muscle, maintaining composition, or preparing for competition. Let’s dive into the science and strategies behind performance nutrition that works.
Understanding Fueling Basics
The foundation of athlete nutrition lies in energy balance the relationship between energy consumed and expended. For peak performance, precise fuel management trumps simply eating healthy foods.
Macronutrients serve specific roles in athletic function. Carbohydrates are the primary energy source for high-intensity activity, with athletes needing 3-5g per kilogram of body weight daily for light activity and up to 8-12g for intense training. Proteins support muscle repair and growth but are rarely used for energy, with strength athletes requiring 0.7-0.8g per pound of body weight. Fats aid cell membrane structure and muscle metabolism, ideally comprising 20-35% of total calories.
Energy availability (EA) is calculated as dietary energy intake minus exercise energy expenditure, normalized to fat-free mass. Optimal EA is ≥45 kcal per kilogram fat-free mass daily. Falling below 30 kcal/kg FFM/day creates low energy availability (LEA), which can lead to RED-S, affecting multiple body systems. Signs include decreased performance, fatigue, frequent injuries (like my stress fracture from underfueling), and compromised recovery. Persistent underfueling also lowers basal metabolic rate, complicating weight management.
Designing a nutrition plan requires balancing macronutrients based on your activity level and training demands.
Building a Performance-Focused Diet
An effective nutrition plan starts with optimizing carbohydrate intake, the primary fuel for high-intensity performance. Endurance athletes should consume 6-10g/kg of carbohydrates daily, and up to 12g/kg for extreme endurance activities like ultramarathons. For my 100-mile races, I target 80-90g of carbohydrates per hour during runs exceeding two hours, using gels, chews, and sports drinks to maintain steady energy. These should come from whole grains, fruits, vegetables, and potatoes.
Protein intake of 1.6-2.2g/kg daily maximizes muscle protein synthesis. Strength athletes may need the higher end, while endurance athletes can target the lower end. High-quality protein sources include lean meats, eggs, dairy, and plant-based options like legumes.
Dietary fat should comprise 20-35% of calories, emphasizing unsaturated fats from olive oil, avocados, nuts, and fatty fish to support hormone production and reduce inflammation.
Micronutrients, including vitamins B, C, D, and minerals like iron, magnesium, and zinc, support energy production and oxygen delivery. For optimal recovery, consume carbohydrates (0.5-0.6g/kg) every 30 minutes for 2-4 hours post-exercise. Protein should be evenly distributed across meals.
When in a caloric deficit, such as during weight-cutting phases, I drink carbohydrate powder during lifting sessions. This provides a quick energy source to fuel workouts, sparing muscle glycogen and preventing performance drops, which is critical when energy intake is limited.
Whole foods should form the diet’s foundation, with supplements used only for specific deficiencies under professional guidance.
Hydration and Supplement Strategy
Proper hydration is a cornerstone of athlete nutrition. Dehydration of just 2% body weight reduces strength by ~5.5% and anaerobic power by ~5.8%. Maintaining fluid balance is critical to avoid performance declines and injuries like my stress fracture, which was exacerbated by underfueling and poor hydration.
Pre-exercise, consume 16-24 ounces of fluid 2-3 hours before activity, plus 7-10 ounces 10-20 minutes prior. During exercise, aim for 6-12 ounces every 10-20 minutes. Plain water suffices for activities under 60 minutes, but for sessions exceeding one hour especially over two hours, where I consume 80-90g of carbs per hour sports drinks with electrolytes (20-25 mmol/L sodium) help maintain blood osmolality and fluid retention, particularly in hot or sweaty conditions.
Post-exercise, replace each pound of weight lost with 16-24 ounces of fluid. Beverages with electrolytes and carbohydrates aid recovery after intense sessions. Individual sweat rates vary (0.5-3.0 L/hour), so personalized hydration strategies are essential.
Conclusion
Proper fueling is the backbone of athletic success, whether you’re chasing muscle gains or endurance goals like a ultramarathon/IRONMAN. Strategic nutrition impacts performance, recovery, and long-term health, as I learned the hard way when underfueling contributed to a stress fracture 12 weeks before my race.
Energy balance is fundamental, with carbohydrates, proteins, and fats playing distinct roles. Endurance athletes like me rely on 80-90g of carbs per hour for activities over two hours, while strength athletes prioritize higher protein. When in a caloric deficit, I use carbohydrate powder during lifting to maintain energy and protect muscle. Adequate energy availability prevents RED-S and its cascading effects, like injuries and fatigue.
Hydration is equally critical, with personalized strategies based on sweat rate and exercise duration ensuring optimal performance. Electrolyte replacement is vital for long sessions or hot conditions.
The journey to optimal nutrition requires consistent effort and adjustment. Monitor your body’s responses and tweak your plan to meet its unique demands. Proper fueling isn’t just about avoiding GI distress or injuries like stress fractures, it’s about giving your body everything it needs to excel, today and throughout your athletic career.