A Comprehensive Overview of Sports Nutrition Essentials
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A ketogenic diet with low carbohydrates might be advantageous for runners, but its relevance for weightlifters is less clear.
“Effective nutrition can elevate a good athlete to greatness, while poor nutrition can diminish a great athlete's performance.”
Since ancient times, athletes have sought nutritional supplements to boost their performance. Historical accounts from 400–500 B.C. suggest that warriors consumed foods like deer liver and lion heart to enhance their strength and valor.
Today, our enhanced understanding of physiology and metabolism has led to a booming sports nutrition industry worth over 50 billion USD. The ketogenic diet has also found its place in sports nutrition, as athletes utilize it to enhance fat oxidation and improve training results.
But should you adopt this approach?
The answer is complex. Nutrition is highly personalized and varies significantly based on individual metabolism, genetic factors, fitness level, and medical history. This article aims to provide a “crash course” on the fundamentals of sports nutrition, covering topics such as:
- Hydration
- Carbohydrates
- Protein and Protein Supplements
- Fats and Low-Carb Ketogenic Diets
- Branched-Chain Amino Acids, Creatine, and Antioxidant Supplements
Understanding Aerobic vs. Anaerobic Metabolism
During exercise, two primary metabolic pathways are at play. Recognizing these will help us identify which nutrients our body prefers for energy during various activities.
Aerobic metabolism occurs when oxygen is present, which is typical during endurance activities like cycling, swimming, and jogging. In this state, our bodies primarily oxidize carbohydrates, fats, or proteins for energy, often favoring fat stores during prolonged exercises.
In contrast, anaerobic metabolism takes place when oxygen levels are low, such as during strength training, high-intensity interval training (HIIT), or short sprints. Under these conditions, our body relies on carbohydrates from glycogen through the anaerobic lactic acid cycle, which leads to lactic acid build-up.
1. Importance of Hydration
Water is the original nutritional supplement. The heat generated by our muscles during physical activity can lead to significant water loss. Dehydration negatively impacts strength, endurance, cognitive function, and recovery, with losses ranging from 0.5 to 2 liters per hour for some athletes.
However, over-hydration poses risks too. Hyponatremia, or low sodium levels in the blood, can result from excessive water intake combined with salt loss through sweat, potentially endangering health more than dehydration. A sports drink with sodium, electrolytes, and carbohydrates can be beneficial during prolonged activities lasting more than two hours.
Listening to thirst cues and hydrating at regular intervals generally suffices for most athletes, with a recommendation of 400–800 ml of water per hour during exercise.
2. Carbohydrates
Carbohydrates serve as the primary energy source during high-intensity anaerobic activities, especially when exerting more than 70% of VO2 max. This is supported by both basic biochemistry and extensive scientific research.
Carbohydrates generate more ATP (the energy currency of our cells) per volume of oxygen than proteins or fats. As exercise intensity increases, our breathing rate rises, reducing oxygen availability. Thus, our bodies prefer oxidizing glucose into lactic acid for energy.
When glycogen stores in muscles and the liver are depleted, it is often described as “hitting the wall,” leading to fatigue. Therefore, maximizing glycogen storage is vital in all aspects of sports nutrition.
How Much Carbohydrate Should I Consume?
Carbohydrate needs differ significantly among individuals, but athletes typically require 5–7 g/kg of body weight daily. Athletes can utilize various strategies to fulfill their carbohydrate requirements and optimize glycogen stores.
Meals should ideally be consumed 3–4 hours before exercise, including at least 60g of high-quality carbohydrate sources, such as whole grains, to allow for digestion and glycogen incorporation. If exercising within an hour, it’s beneficial to consume 1–4 g/kg of high-glycemic, low-fiber carbohydrates for swift glycogen replenishment.
During extended activities, consuming 30–60 g of carbohydrates (like sports gels or gummies) is recommended, particularly in intermittent sports like soccer and basketball. Post-exercise, replenishing with 1.0 -1.2 g/kg of carbohydrates, alongside protein and fluids, within 4–6 hours is essential for those training daily.
What Exactly Are Carbohydrates?
For more information on carbohydrates, refer to my detailed article.
3. Protein
Muscle protein synthesis (MPS) is crucial for muscle growth and mass increase. MPS is triggered by the intake of essential amino acids, the fundamental building blocks of dietary protein.
The amino acid leucine plays a pivotal role in stimulating MPS but is most effective when consumed as part of complete proteins rather than in isolation. Therefore, the whole foods you consume, including both animal and plant proteins, are likely adequate.
For those aiming for muscle hypertrophy, protein supplementation can enhance gains in both type I and II muscle fibers during resistance training programs lasting over six weeks. If you choose to supplement, opt for products containing primarily whey or pea protein isolates, as they provide complete protein with a high leucine content.
What About BCAAs?
Branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—are often marketed as supplements for enhancing MPS. However, relying solely on BCAAs can lead to 50% less MPS compared to complete protein sources, as they lack five of the nine essential amino acids. Remember, BCAAs are most effective when consumed within a complete protein context.
How Much Protein Should I Consume?
The timing of protein consumption post-exercise, along with total daily intake, is vital for muscle repair and stimulating MPS. Consuming 20–30 g of protein, including at least 10 g of essential amino acids, within an hour after exercise is advisable. Follow this with another meal within 3–5 hours, as studies indicate that MPS peaks occur 3–5 hours apart.
The recommended daily protein intake for athletes ranges from 1.2 to 2.0 g/kg, with MPS up-regulated for 24 hours post-exercise, underscoring the importance of consistent protein intake throughout the day.
4. Fats and Ketogenic Diets
While glucose is often seen as the primary fuel source, the situation changes for endurance athletes operating below 70% of VO2 max, who primarily oxidize fat for energy, conserving glycogen for bursts of effort.
Training on a low-carbohydrate, ketogenic diet can enhance fat oxidation, allowing endurance athletes to optimize energy from fat and improve training outcomes. However, you don’t need to strictly follow a ketogenic diet to reap these benefits, as similar effects can arise from fasted cardio, where glycogen stores are low.
Why Avoid Ketogenic Diets for Strength Training?
Increasing fat oxidation through a ketogenic diet simultaneously reduces glucose oxidation, which can hinder performance in strength training contexts where glucose is the more efficient energy source under anaerobic conditions.
However, opting out of a high-fat diet doesn’t mean embracing a low-fat approach. Diets with less than 20% of energy from fats risk deficiencies in essential omega-3 and omega-6 fatty acids.
5. Are Sports Nutrition Supplements Worth It?
Optimizing nutrition should begin with whole, high-quality foods, as they cannot be matched by supplements. These products can never compensate for poor dietary habits, lack of sleep, or inadequate training.
Nonetheless, some athletes might contemplate adding supplements to their diets. In the U.S., nutritional supplements are not regulated. Always consult with a healthcare provider or dietitian before incorporating them into your routine.
Creatine
What is it? Creatine is not a steroid. It is an organic compound synthesized from the amino acids glycine, arginine, and methionine. Our bodies produce creatine, which aids in delivering ATP to our muscles. It’s also found in animal proteins, with vegetarians typically having lower muscle creatine levels.
What does it do? During high-intensity anaerobic exercise, muscles can deplete ATP within 8–10 seconds. Creatine can extend this duration by providing additional ATP. Research supports creatine’s positive impact on muscle growth, performance enhancement, and cognitive function.
How should I supplement? Creatine requires a loading phase for muscle saturation. The International Society of Sports Nutrition (ISSN) recommends 5 g four times a day for 5–7 days, followed by a maintenance dose of 3–5 g daily. Insulin enhances creatine absorption, making it advisable to take it with a meal containing protein and carbohydrates. Creatine monohydrate is the most bioavailable form.
Antioxidant Supplements
What are they? Antioxidant supplements include omega-3 fatty acids and vitamins C and E.
How do they work? Antioxidants, produced by our bodies and found in colorful fruits and vegetables, combat oxidation by reducing reactive oxygen species (ROS) in the body. Antioxidant supplements gained popularity due to claims of reducing inflammation and accelerating recovery.
However, exercise naturally induces inflammation, and athletes adapt by enhancing their internal antioxidant systems. Trained athletes possess higher antioxidant levels than untrained individuals. Relying on supplements can hinder this adaptation, ultimately impairing the body’s natural repair and recovery processes.
How should I supplement? Avoid supplements and focus on consuming antioxidant-rich foods post-exercise, such as blueberries, raspberries, and dark leafy greens.
Conclusion
Sports nutrition can be complex, but the foundation lies in consuming adequate calories along with quality carbohydrates, proteins, and fats. Don't overlook the importance of proper hydration and sleep in optimizing performance.
Key nutritional takeaways include:
- Carbohydrates are essential for high-intensity anaerobic exercises, including weightlifting, HIIT, and sprinting. Aim for 5–7 g/kg of carbohydrates daily.
- Protein intake is crucial throughout the day for athletes, with a recommendation of 20–30 g of protein within two hours post-workout to optimize MPS.
- Low-carbohydrate ketogenic diets can benefit endurance athletes, as fat oxidation becomes their primary energy source.
Lastly, remember that sports nutrition is highly individualized; each athlete’s metabolism, gene expression, fitness level, and medical history varies. Consulting with a sports dietitian is the best approach to enhance performance.
> Kristen Sunstrum is a dietetics student who believes nutrition extends beyond healthy foods.