Sports Nutrition for Athletes

Sports Nutrition

• This presentation outlines dietary requirements for athletes, comparing them to normal adult requirements.

Objectives

• Outline dietary requirements of athletes compared to normal requirements
• Outline supplements commonly used and the scientific basis behind their use
• Present an argument for or against using supplements

Dietary Requirements for Normal Adults

• Energy: 2000 Kcalories per day
• Protein: 50 grams per day
• Fat: 70 grams per day
• Saturated Fatty Acids: 24 grams per day
• Carbohydrates: 310 grams per day
• Sugars: 90 grams per day
• Dietary Fiber: 30 grams per day
• Sodium (salt): 2.3 grams per day

Energy Requirements for Athletes

• Individual athletes have unique energy requirements to meet total nutritional goals.
• Daily energy requirements can be estimated based on resting metabolic rate (RMR) and activity levels.
• Research methods like indirect calorimetry and doubly labeled water (DLW) can measure energy requirements. These methods can confirm situations of abnormal energy balance in athletes.

Common Concerns in Athletes

• Many athletes focus excessively on reducing body mass and body fat to inconsistent levels with long-term health and performance.
• Restrained eating can negatively impact body function.
• Leptin may play a role in modulating these changes.

Daily Calorie Needs

• Calorie needs vary based on age, gender, and activity level. A table provides calorie ranges for different activity levels (sedentary, moderately active, and active) across various age groups (2-3 to 51 and older).

Carbohydrates

• Official dietary guidelines recommend high carbohydrate intake for athletes.
• Carbohydrate intake should be 5-7 grams per kilogram of body weight per day for general training, and 7-10 grams per kilogram of body weight per day for endurance athletes.
• Carbohydrates are crucial for peak performance during physical activity, providing energy and supporting muscle growth.
• Without enough stored glucose, the body will use other nutrients (like fat and protein) for energy.
• Adequate carbohydrates allow protein to focus on muscle repair and building, maximizing muscle growth.

Protein

• The Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight per day for adults.
• This RDA maintains nitrogen balance in the body, preventing muscle breakdown for energy.
• Recent studies suggest that athletes, active individuals, and older adults may need more protein than the RDA to optimize health.

Protein Guidelines

• Develop a meal plan to supply adequate calories, carbohydrates, and protein.
• Distribute protein evenly across meals for optimal muscle protein synthesis.
• Prioritize high-quality protein sources.
• Base protein intake on weight, not percentage of calories.
• Tailor protein intake to an individual’s sport and intensity level. Protein-Rich Foods:
• Beef steak (3.5 oz): 29g
• Salmon (4 oz): 29g
• Lentils (1 cup): 18g
• Greek yogurt (5 oz): 14g
• Skim milk (8 oz): 8g
• Tofu, firm (3.5 oz): 7g
• Egg (1 large): 6g

Fat

• Adequate fat intake is essential for many metabolic activities and optimal health.
• Vitamins A, D, and E require fat for absorption.
• Athletes should aim for a fat intake between 20-35% of total daily calories.
• Dietary guidelines recommend 10% of fat intake from monounsaturated sources, 10% from polyunsaturated sources, and no more than 10% from saturated fat.

Effect of Diet on Physical Endurance

• A higher intake of carbohydrates has been linked to longer maximum endurance times, compared to lower carbohydrate diets and diets high in fat and protein.

Micronutrients

• Micronutrients play important roles in health, energy production, blood synthesis, bone health, and immune function.
• They are also crucial for muscle and tissue repair during recovery.
• Vegetarian athletes might have an increased risk of low intakes of iron, calcium, vitamin D, riboflavin, zinc and vitamin B12.

Female Athletes

• Female athletes frequently have lower nutritional intake than male athletes.
• Female athletes, particularly endurance athletes, often have difficulty meeting carbohydrate recommendations due to chronic or periodic restrictions on total energy intake to achieve/maintain low body fat.
• Female athletes involved in sports promoting leanness (e.g., gymnastics, distance running) may struggle with inadequate nutrient intake.
• These athletes may frequently consume less than 70% of recommended daily energy needs.
• Female athletes have an increased risk of deficiencies in iron, calcium, vitamin B, and zinc.