IB Sports, exercise and health science A.2.2.4 Dietary Planning, Nutrient Needs, and Supplementation Notes

A balanced diet provides essential nutrients in the correct proportions

1. A balanced diet is essential for maintaining optimal health, supporting growth, promoting recovery, and performance.
2. It consists of various food components, each serving a distinct role in the body's function.
3. A well-balanced diet provides all the essential nutrients, maintaining the correct proportions to support bodily processes and fuel performance.

Dietary guidelines define recommended nutrient intake

1. Dietary guidelines are structured recommendations based on scientific research, often formulated by health organizations to promote general health and reduce the risk of chronic diseases.
2. They give clear advice on the proper quantities of food and nutrients necessary to maintain optimal health.
3. Recommended Nutrient Intake (RNI): The amount of each nutrient needed for normal body function. It varies by age, sex, activity level, and health status.

Cultural and religious practices shape dietary planning

1. Cultural and religious practices significantly impact dietary choices, leading to variations in the types of food consumed.
2. These factors must be taken into consideration when planning nutrition for diverse populations.
3. Some cultural practices, such as vegetarianism or veganism, can offer health benefits but require careful planning to ensure adequate intake of all essential nutrients.

Nutritional needs vary with age, sex, activity, and reproductive status

Age

1. The nutrient needs of children, adolescents, adults, and older people differ as their growth, development, and metabolism rates change.
2. For instance, adolescents require more protein and energy for growth, while older adults may need more calcium and vitamin D to maintain bone health.

Sex

1. Males and females have different nutritional needs, with women requiring more iron during menstruation and pregnancy, while men may require higher amounts of certain nutrients like zinc.

Physical Activity Level

1. Athletes and physically active individuals need higher energy intake, particularly carbohydrates, for fuel during exercise.
2. Active individuals may also require more protein for muscle repair and growth.

Pregnancy and lactation increase nutrient needs

1. Nutritional requirements increase during pregnancy and breastfeeding to support fetal development and milk production.
2. This includes increased intake of calories, protein, iron, calcium, and folic acid.

Eating for Athletes vs Non-Athletes

1. An athlete's diet must meet higher physiological demands than a non-athlete's, especially increased energy and fluid requirements.
2. Carbohydrate (athletes): 55-75% of total energy (vs 45-65% for non-athletes), or 6-10 g per kg of body mass.
3. Protein (athletes): 1.2-1.4 g per kg body mass per day (vs 0.8-1.0 g per kg for non-athletes).
4. Fat (athletes): 20-35% of total energy (slightly above non-athlete range). Provides fuel for prolonged work, fat-soluble vitamins, and essential fatty acids.
5. Fluid (athletes): Significantly higher to replace heavy sweat losses during training and competition.
6. No protein storage: The body has no storage form of protein. Steady daily intake is required because the amino acid pool is continuously broken down and rebuilt.

Energy needs depend on activity and are met by macronutrient balance

1. Energy needs are based on the amount of energy the body requires to perform essential functions and physical activity.
2. These needs can be measured in kilocalories (kcal).
3. They are determined by factors such as basal metabolic rate (BMR), activity level, and overall health.
4. The three macronutrients, carbohydrates, proteins, and fats play specific roles in providing energy and supporting bodily functions.

Carbohydrates (55-75% of total energy)

1. The primary source of energy, especially during exercise.
2. Carbs are stored in muscles and the liver as glycogen and are the body's main fuel source during physical activity.

Proteins (10-15% of total energy)

1. Essential for tissue growth, muscle repair, and the production of enzymes and hormones.
2. They are also used for energy when carbohydrate stores are low.

Fats (15-30% of total energy)

1. Provide a concentrated source of energy and are crucial for cellular structure, hormone regulation, and fat-soluble vitamin absorption.

International guidelines set recommended nutrient intake ranges

1. Different countries offer guidelines on the optimal intake of nutrients to promote health.
2. These recommendations are provided by organisations such as the World Health Organization (WHO) and national health bodies. They promote dietary patterns that reduce lifestyle diseases such as obesity, heart disease, and diabetes.
3. The WHO recommends fat intake of 15-30% of total energy to balance essential fatty acid needs against chronic disease prevention.
4. The USDA's MyPlate emphasises balancing food groups, encouraging consumption of vegetables, fruits, grains, and proteins.

WHO/FAO General Population Targets

1. Total Fat: 15-30% of total energy intake
2. Saturated Fat: Less than 10% of total energy intake
3. Carbohydrates: 55-75% of total energy intake
4. Protein: 10-15% of total energy intake
5. Sodium (Salt): Less than 5 g per day
6. Fruits and Vegetables: At least 400 g per day for optimal health

Nutritional ergogenic aids can improve performance but have limits

1. Nutritional supplements are used in sport to enhance performance and recovery.
2. While some are backed by scientific evidence, others lack proven benefits.
3. The most commonly used performance-enhancing supplements include:

Caffeine

1. Acts as a central nervous system stimulant, reducing perceived exertion and enhancing endurance and strength performance.
2. Recommended Dose: 2-6 mg/kg body mass before or during exercise.
3. Benefits: Improved endurance, increased force production.
4. Potential Side Effects: Insomnia, anxiety, mild diuretic effects.

Creatine

1. Increases muscle creatine phosphate stores, improving short-duration, high-intensity exercise performance.
2. Recommended Dose: 15-20 g/day for 4-7 days (loading phase), followed by 2 g/day maintenance.
3. Benefits: Enhanced power output, increased muscle mass.
4. Potential Side Effects: Weight gain due to water retention.

Bicarbonate

1. Acts as a buffer to reduce muscle acidity, delaying fatigue in high-intensity activities (most effective for efforts lasting 1-7 minutes).
2. Recommended Dose: 0.3 g/kg before exercise.
3. Benefits: Improved tolerance to anaerobic exercise.
4. Potential Side Effects: Gastrointestinal discomfort.

Emerging Supplements

1. Beta-alanine: Acts on intramuscular buffering and may help with 1-4 minute sustained efforts.
2. L-arginine: May increase vasodilation and oxygen delivery.
3. Dietary nitrate (beetroot juice): May improve oxygen efficiency during sub-maximal exercise.
4. Caveat: Athletes should check that any supplement is permitted under their sport's anti-doping rules (e.g., Australian Institute of Sport classification) before using it.

1. While supplements can provide performance benefits, they should be used alongside a well-balanced diet and proper training.

Gastrointestinal Discomfort During Exercise

1. GI problems are common in endurance sport and one of the most frequent causes of underperformance.
2. Symptoms include nausea, vomiting, diarrhoea, bloating, and urgency.

Causes

1. Physiological: During exercise, blood flow to the intestines drops as it is redirected to working muscle. The gut is starved of oxygen and stops working efficiently.
2. Mechanical: Repetitive jostling damages the intestinal lining (more in runners than cyclists). Cyclists in the aerodynamic position experience more upper-GI symptoms because of abdominal pressure.
3. Nutritional: High-fibre foods, high-fat meals, large fructose doses, dehydration, and very concentrated carbohydrate drinks all increase risk.

Practical Advice for Athletes

1. Avoid high-fibre foods: In the day or days before competition.
2. Avoid aspirin and some NSAIDs: Ibuprofen and similar drugs increase intestinal permeability and worsen GI symptoms during long efforts.
3. Avoid high-fructose foods or drinks: A glucose-fructose mix is better tolerated than fructose alone.
4. Start the session well hydrated: Dehydration makes every GI symptom worse.
5. Choose lower carbohydrate concentrations: Very concentrated drinks sit in the stomach longer.
6. Practise nutrition strategies in training: Never try new fuels, drinks, or supplements for the first time on race day.