Title: Sports Nutrition — LearnCoachAssist

Q: What are the three macronutrients?
A: The three macronutrients are protein, carbohydrates, and fats. Each provides energy: protein and carbs yield ~4 kcal/g, while fat yields ~9 kcal/g.

Q: How much protein per day is generally recommended for athletes?
A: Most sports nutrition guidelines recommend 1.2–2.0 g of protein per kg of body weight per day for athletes, depending on the sport and training intensity. Endurance athletes need ~1.2–1.4 g/kg; strength athletes need ~1.6–2.0 g/kg.

Q: What is the primary role of carbohydrates in sports performance?
A: Carbohydrates are the body's preferred fuel source during moderate-to-high intensity exercise. They are stored as glycogen in muscles and liver, providing readily available energy for athletic performance.

Q: What is glycogen and why is it important for athletes?
A: Glycogen is the stored form of glucose found in muscles (~300–400 g) and the liver (~75–100 g). It is the primary fuel for exercise above ~65% VO2max and its depletion leads to fatigue and reduced performance.

Q: What are simple vs complex carbohydrates?
A: Simple carbs (monosaccharides, disaccharides) are quickly digested and raise blood sugar rapidly (e.g., fruit, sugar, honey). Complex carbs (polysaccharides) digest more slowly and provide sustained energy (e.g., oats, rice, potatoes).

Q: How much carbohydrate should endurance athletes consume daily?
A: Endurance athletes typically need 6–10 g of carbohydrate per kg of body weight per day, depending on training volume and intensity. During ultra-endurance events, needs may exceed 10 g/kg/day.

Q: What is the role of dietary fat in athletic performance?
A: Dietary fat provides essential fatty acids, supports hormone production (including testosterone), aids absorption of fat-soluble vitamins (A, D, E, K), and serves as a fuel source during low-intensity and prolonged exercise.

Q: What is the recommended fat intake for athletes?
A: Athletes should consume 20–35% of total daily calories from fat. Intake below 20% can impair hormone production and fat-soluble vitamin absorption. Emphasis should be on unsaturated fats.

Q: What are omega-3 fatty acids and why are they important for athletes?
A: Omega-3s (EPA and DHA) are essential polyunsaturated fatty acids found in fatty fish, flaxseed, and walnuts. They reduce inflammation, support cardiovascular health, may improve recovery, and have been linked to reduced exercise-induced muscle soreness.

Q: What is the difference between saturated and unsaturated fats?
A: Saturated fats have no double bonds between carbon atoms (solid at room temperature, e.g., butter). Unsaturated fats have one or more double bonds (liquid at room temperature, e.g., olive oil). Unsaturated fats are generally considered healthier.

Q: What is the biological value (BV) of a protein?
A: Biological value measures the proportion of absorbed protein that is retained and used by the body. Whole egg has a BV of 100 (reference), whey protein ~104, casein ~77, and soy ~74.

Q: What is a complete protein?
A: A complete protein contains all nine essential amino acids in adequate amounts: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Examples include meat, fish, eggs, dairy, soy, and quinoa.

Q: What are BCAAs and what do they do?
A: Branched-Chain Amino Acids (leucine, isoleucine, valine) make up ~35% of muscle protein. Leucine is the key trigger for muscle protein synthesis (mTOR pathway). BCAAs may reduce exercise-induced muscle damage and perceived fatigue.

Q: What is the anabolic window?
A: The anabolic window is the supposed 30–60 minute post-exercise period when nutrient uptake is enhanced. Current research suggests this window is wider than originally thought (several hours), and total daily protein intake matters more than precise timing.

Q: What is nutrient timing?
A: Nutrient timing is the strategic consumption of specific nutrients at specific times relative to exercise to optimize performance, recovery, and body composition. Key periods include pre-workout, intra-workout, and post-workout nutrition.

Q: What should a pre-workout meal contain?
A: A pre-workout meal (eaten 2–4 hours before exercise) should contain moderate protein (20–40 g), complex carbohydrates for sustained energy, and low-to-moderate fat. Example: chicken breast with rice and vegetables.

Q: What should a post-workout meal contain?
A: A post-workout meal should include protein (20–40 g) to stimulate muscle protein synthesis and carbohydrates (0.8–1.2 g/kg) to replenish glycogen stores. Consuming this within 2 hours post-exercise is generally recommended.

Q: What is the glycemic index (GI)?
A: The glycemic index ranks carbohydrates on a scale of 0–100 based on how quickly they raise blood glucose. High GI foods (>70) cause rapid spikes; low GI foods (<55) produce slower, sustained rises. Medium GI is 56–69.

Q: When should high-GI foods be consumed by athletes?
A: High-GI foods are best consumed during and immediately after exercise when rapid glycogen replenishment and quick energy are beneficial. Examples include white bread, sports drinks, white rice, and ripe bananas.

Q: How much water should an athlete drink daily?
A: General guideline: at least 3–4 liters per day for active individuals. A more precise method: drink enough to maintain pale yellow urine. During exercise, aim for 400–800 mL/hour depending on sweat rate and conditions.

Q: What are the signs of dehydration?
A: Signs include dark yellow urine, thirst, dry mouth, headache, dizziness, fatigue, decreased performance, elevated heart rate, and reduced sweat rate. Even 2% body weight loss from fluid can impair performance by 10–20%.

Q: What are electrolytes and why do athletes need them?
A: Electrolytes are minerals that carry an electrical charge: sodium, potassium, chloride, calcium, magnesium. They regulate fluid balance, nerve function, and muscle contraction. Athletes lose them through sweat, especially sodium (500–1500 mg/L of sweat).

Q: What is hyponatremia?
A: Hyponatremia is dangerously low blood sodium levels (<135 mmol/L), often caused by drinking excessive water without adequate sodium replacement during prolonged exercise. Symptoms include nausea, confusion, seizures; can be fatal.

Q: What is creatine and how does it work?
A: Creatine is a naturally occurring compound stored as phosphocreatine in muscles. It regenerates ATP during short, high-intensity efforts (the phosphagen system). Supplementing increases muscle creatine stores by 20–40%, improving power output and recovery.

Q: What is the recommended creatine dosage?
A: The standard protocol is a loading phase of 20 g/day (split into 4 doses) for 5–7 days, followed by a maintenance dose of 3–5 g/day. Alternatively, taking 3–5 g/day without loading saturates muscles in ~28 days.

Q: Is creatine safe for long-term use?
A: Yes. Creatine monohydrate is one of the most studied and safest supplements available. Research spanning decades shows no adverse effects on kidney or liver function in healthy individuals at recommended doses.

Q: What is whey protein?
A: Whey protein is a fast-digesting, complete protein derived from milk during cheese production. It is rich in BCAAs (especially leucine) and has a high biological value. Types include concentrate (~80% protein), isolate (~90%), and hydrolysate (pre-digested).

Q: What is the difference between whey concentrate, isolate, and hydrolysate?
A: Concentrate: 70–80% protein, contains some fat and lactose. Isolate: 90%+ protein, minimal fat/lactose, faster absorption. Hydrolysate: pre-digested for fastest absorption, most expensive. All are effective; isolate is best for lactose-intolerant individuals.

Q: What is casein protein?
A: Casein is a slow-digesting milk protein that forms a gel in the stomach, providing a sustained release of amino acids over 6–8 hours. It is often recommended before bed to support overnight muscle protein synthesis.

Q: What are the benefits of caffeine for exercise?
A: Caffeine reduces perceived exertion, increases alertness, enhances endurance performance (3–5%), and may improve strength and power output. Effective dose: 3–6 mg/kg body weight, consumed 30–60 minutes before exercise.

Q: What is beta-alanine?
A: Beta-alanine is an amino acid that increases intramuscular carnosine levels, which buffers hydrogen ions during high-intensity exercise. It reduces fatigue during efforts lasting 1–4 minutes. Common dose: 3–6 g/day. May cause harmless tingling (paresthesia).

Q: What is citrulline malate?
A: Citrulline malate increases nitric oxide production and arginine levels, improving blood flow and reducing fatigue. It may enhance endurance performance and reduce muscle soreness. Typical dose: 6–8 g taken 30–60 minutes pre-exercise.

Q: What are pre-workout supplements?
A: Pre-workout supplements typically contain a blend of caffeine, beta-alanine, citrulline, creatine, and/or nitric oxide precursors. They aim to increase energy, focus, blood flow, and performance. Effects vary by ingredient quality and dosage.

Q: What is a calorie?
A: A calorie (technically kilocalorie, kcal) is a unit of energy. It represents the energy needed to raise the temperature of 1 kg of water by 1°C. In nutrition, it measures the energy content of foods and the energy expenditure of activities.

Q: How do you calculate Total Daily Energy Expenditure (TDEE)?
A: TDEE = BMR × Activity Factor. BMR (Basal Metabolic Rate) can be estimated using equations like Mifflin-St Jeor. Activity factors: sedentary (1.2), light (1.375), moderate (1.55), active (1.725), very active (1.9).

Q: What is the Mifflin-St Jeor equation?
A: For males: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 5. For females: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. It is considered the most accurate BMR prediction equation.

Q: What is a caloric surplus and when is it used?
A: A caloric surplus means consuming more calories than you expend. It is used for muscle gain (bulking). A moderate surplus of 250–500 kcal/day above TDEE promotes muscle growth while minimizing fat gain.

Q: What is a caloric deficit and when is it used?
A: A caloric deficit means consuming fewer calories than you expend. It is necessary for fat loss. A moderate deficit of 300–500 kcal/day below TDEE promotes fat loss while preserving muscle mass (with adequate protein and resistance training).

Q: What is the thermic effect of food (TEF)?
A: TEF is the energy required to digest, absorb, and process nutrients. Protein has the highest TEF (~20–30% of calories consumed), followed by carbohydrates (~5–10%) and fat (~0–3%). TEF accounts for ~10% of total daily energy expenditure.

Q: What is carb loading?
A: Carb loading is a strategy to maximize glycogen stores before endurance events lasting >90 minutes. The modern approach involves eating 8–12 g carbs/kg/day for 1–3 days before competition while tapering training.

Q: What are micronutrients?
A: Micronutrients are vitamins and minerals required in small amounts for essential bodily functions. They do not provide energy but are critical for metabolism, immune function, bone health, and hundreds of enzymatic reactions.

Q: Why is iron important for athletes?
A: Iron is essential for hemoglobin (oxygen transport in blood) and myoglobin (oxygen storage in muscle). Iron deficiency impairs endurance performance, causes fatigue, and is common in female athletes and endurance athletes. RDA: 8 mg (males), 18 mg (females).

Q: Why is calcium important for athletes?
A: Calcium is critical for bone health, muscle contraction, nerve signaling, and blood clotting. Athletes, especially females, need adequate calcium (1000–1300 mg/day) to prevent stress fractures and osteoporosis.

Q: What is vitamin D's role in athletic performance?
A: Vitamin D supports calcium absorption, bone health, immune function, and muscle function. Deficiency is linked to increased injury risk, impaired recovery, and reduced performance. Many athletes are deficient, especially those training indoors. Recommended: 1000–2000 IU/day.

Q: What are the B vitamins' roles in sports nutrition?
A: B vitamins are coenzymes in energy metabolism. B1 (thiamine), B2 (riboflavin), and B3 (niacin) are involved in energy production. B6 aids protein metabolism. B12 and folate support red blood cell production. Athletes with restricted diets may need supplementation.

Q: What is magnesium's role for athletes?
A: Magnesium is involved in 300+ enzymatic reactions including energy production, muscle contraction, protein synthesis, and nerve function. Deficiency can cause cramps, fatigue, and impaired performance. Athletes may need 400–600 mg/day. Found in nuts, seeds, leafy greens.

Q: What is zinc's role for athletes?
A: Zinc supports immune function, protein synthesis, testosterone production, and wound healing. Exercise increases zinc loss through sweat and urine. RDA: 11 mg (males), 8 mg (females). Found in meat, shellfish, legumes, and seeds.

Q: What is the Female Athlete Triad?
A: The Female Athlete Triad consists of three interrelated conditions: low energy availability (with or without disordered eating), menstrual dysfunction (amenorrhea), and low bone mineral density (osteoporosis). It is now part of the broader concept of Relative Energy Deficiency in Sport (RED-S).

Q: What is RED-S (Relative Energy Deficiency in Sport)?
A: RED-S describes impaired physiological function caused by low energy availability, affecting both males and females. It impacts metabolism, menstrual function, bone health, immunity, protein synthesis, cardiovascular health, and psychological well-being.

Q: How much protein should be consumed per meal to maximize muscle protein synthesis?
A: Research suggests 20–40 g of high-quality protein per meal maximally stimulates muscle protein synthesis. The leucine threshold of ~2.5–3 g per meal is key. Larger individuals and older adults may benefit from the higher end of this range.

Q: What is the role of leucine in muscle protein synthesis?
A: Leucine is the primary amino acid trigger for the mTOR signaling pathway, which activates muscle protein synthesis. A threshold of approximately 2.5–3 g of leucine per meal is needed to maximally stimulate this response.

Q: What are the best protein sources for muscle building?
A: Top sources include chicken breast, lean beef, fish (salmon, tuna), eggs, Greek yogurt, cottage cheese, whey protein, and plant sources like tofu, tempeh, and lentils. Quality is determined by amino acid profile and digestibility (DIAAS score).

Q: What is the DIAAS scoring system?
A: Digestible Indispensable Amino Acid Score evaluates protein quality based on the digestibility of individual essential amino acids. It replaced the older PDCAAS method. Scores >100 are excellent (e.g., milk, eggs); plant proteins typically score lower.

Q: What are the effects of alcohol on sports performance?
A: Alcohol impairs muscle protein synthesis, dehydrates the body, disrupts sleep quality, reduces glycogen resynthesis, impairs reaction time, and can increase injury risk. Even moderate consumption post-exercise can significantly hinder recovery.

Q: What is intermittent fasting and how does it affect athletes?
A: Intermittent fasting involves cycling between eating and fasting periods (e.g., 16:8, 5:2). While it may aid fat loss, it can impair performance and muscle gain if total calorie and protein intake is insufficient or if training occurs in fasted states.

Q: What is the ketogenic diet?
A: The ketogenic diet is a very low-carb, high-fat diet (typically <50 g carbs/day) that forces the body to use fat/ketones as primary fuel. It may benefit ultra-endurance athletes but generally impairs high-intensity performance due to reduced glycogen availability.

Q: What should athletes eat during prolonged exercise?
A: During exercise lasting >60 minutes, consume 30–60 g of carbohydrates per hour from easily digestible sources (sports drinks, gels, bananas). For events >2.5 hours, intake can be increased to up to 90 g/hour using glucose + fructose combinations.

Q: What is the 2:1 glucose-to-fructose ratio?
A: Using a 2:1 ratio of glucose to fructose allows absorption of up to ~90 g carbs/hour by utilizing two different intestinal transport pathways (SGLT1 for glucose, GLUT5 for fructose), compared to ~60 g/hour from glucose alone.

Q: What is sodium bicarbonate loading?
A: Sodium bicarbonate (baking soda) is an extracellular buffer that can improve performance in high-intensity efforts lasting 1–7 minutes by neutralizing hydrogen ions. Typical dose: 0.2–0.3 g/kg taken 60–90 minutes pre-exercise. May cause GI distress.

Q: What is the role of antioxidants in sports nutrition?
A: Antioxidants (vitamins C, E, selenium, polyphenols) neutralize free radicals produced during exercise. However, excessive supplementation may blunt training adaptations, as some oxidative stress is needed for adaptation signaling. Whole foods are preferred over supplements.

Q: How does protein intake differ for endurance vs strength athletes?
A: Endurance athletes: 1.2–1.4 g/kg/day to repair tissue and support immune function. Strength athletes: 1.6–2.2 g/kg/day to support muscle growth and repair. Both benefit from distributing protein evenly across 4–5 meals.

Q: What is sports anemia?
A: Sports anemia (pseudoanemia) is a dilutional decrease in hemoglobin concentration caused by expanded plasma volume in endurance athletes. It is a normal adaptation, not true anemia, and does not impair performance. True iron-deficiency anemia requires treatment.

Q: What is glycogen supercompensation?
A: Glycogen supercompensation is the process of loading muscles with more glycogen than normal (up to 150–200% of resting levels) through a combination of glycogen-depleting exercise followed by high-carbohydrate intake (8–12 g/kg/day) for 1–3 days.

Q: What is the Randle cycle?
A: The Randle cycle (glucose-fatty acid cycle) describes the competition between glucose and fatty acids for oxidation. When fat availability is high, fat oxidation increases and glucose oxidation decreases, and vice versa. This is relevant for understanding fuel selection during exercise.

Q: What is the crossover concept in exercise metabolism?
A: The crossover concept states that as exercise intensity increases, the body shifts from fat oxidation to carbohydrate oxidation as the primary fuel source. The crossover point typically occurs at ~65% VO2max, varying with training status and diet.

Q: What are medium-chain triglycerides (MCTs)?
A: MCTs are fats with 6–12 carbon chains that are rapidly absorbed and transported directly to the liver for oxidation. They provide quick energy but their ergogenic benefit is limited and may cause GI distress at effective doses. Found in coconut oil.

Q: How does fiber affect athletic performance?
A: Fiber supports gut health, blood sugar regulation, and satiety. However, high-fiber foods should be avoided 2–3 hours before exercise as they can cause GI discomfort. Athletes should aim for 25–35 g/day, timed away from training.

Q: What is the role of tart cherry juice in recovery?
A: Tart cherry juice contains anthocyanins and anti-inflammatory compounds that may reduce muscle soreness (DOMS), lower inflammation markers, and improve sleep quality due to natural melatonin content. Typical dose: 8–12 oz twice daily around training.

Q: What is HMB (beta-hydroxy beta-methylbutyrate)?
A: HMB is a metabolite of leucine that may reduce muscle protein breakdown and support recovery. It appears most effective for untrained individuals or during caloric restriction. Typical dose: 3 g/day divided into 3 doses. Benefits for trained athletes are less clear.

Q: What is nitrate supplementation (e.g., beetroot juice)?
A: Dietary nitrate (from beetroot juice) is converted to nitric oxide, which improves blood flow, reduces oxygen cost of exercise, and enhances muscle efficiency. It can improve endurance performance by 1–3%. Effective dose: ~6–8 mmol nitrate taken 2–3 hours pre-exercise.

Q: What is the difference between essential and non-essential amino acids?
A: Essential amino acids (EAAs) cannot be synthesized by the body and must come from diet (9 total). Non-essential amino acids can be produced by the body. Conditionally essential amino acids (e.g., glutamine) become essential during illness or stress.

Q: What is glutamine and is supplementation beneficial for athletes?
A: Glutamine is the most abundant amino acid in the body, important for immune function and gut health. Intense exercise depletes glutamine levels. Supplementation (5–10 g/day) may support immune function in heavily training athletes, but evidence for muscle-building benefits is weak.

Q: What is the importance of sleep for recovery nutrition?
A: Sleep is critical because growth hormone is primarily released during deep sleep, facilitating muscle repair. Poor sleep increases cortisol, impairs glycogen replenishment, and increases appetite. A casein protein shake before bed can provide sustained amino acids during sleep.

Q: What is periodized nutrition?
A: Periodized nutrition involves adjusting calorie and macronutrient intake based on training phase. During high-volume training: more carbs. During strength phases: more protein. During off-season: moderate intake. This optimizes performance, body composition, and recovery throughout the training year.

Q: How do you calculate macronutrient ratios?
A: First determine calorie needs (TDEE). Then set protein (1.6–2.2 g/kg), fat (20–35% of calories), and fill remaining calories with carbohydrates. Example for 80 kg athlete at 3000 kcal: protein 160 g (640 kcal), fat 83 g (750 kcal), carbs 403 g (1610 kcal).

Q: What is the difference between weight loss and fat loss?
A: Weight loss includes loss of fat, muscle, water, and glycogen. Fat loss specifically targets adipose tissue. To maximize fat loss while preserving muscle: maintain a moderate deficit, keep protein high (2.0+ g/kg), perform resistance training, and lose 0.5–1% body weight per week.

Q: What is metabolic adaptation (adaptive thermogenesis)?
A: Metabolic adaptation is the body's reduction in energy expenditure beyond what is predicted by weight loss. It includes decreased BMR, reduced NEAT (non-exercise activity), improved movement efficiency, and hormonal changes (lower leptin, thyroid). It makes continued fat loss progressively harder.

Q: What are diet breaks and refeeds?
A: Diet breaks are planned periods (1–2 weeks) of eating at maintenance calories during a fat loss phase. Refeeds are shorter (1–2 days) periods of increased carbohydrate intake. Both may help counteract metabolic adaptation, reduce psychological stress, and restore leptin levels.

Q: What is the importance of sodium for athletes?
A: Sodium is the primary electrolyte lost in sweat (average 500–1500 mg/L). It regulates fluid balance, nerve impulses, and muscle contractions. Athletes exercising >1 hour, especially in heat, should replace sodium to prevent hyponatremia and maintain performance.

Q: What are sports drinks and when should they be used?
A: Sports drinks contain water, carbohydrates (6–8%), and electrolytes. They are beneficial during exercise lasting >60 minutes or in hot conditions. For exercise <60 minutes, water is usually sufficient. Examples: isotonic drinks match blood osmolality for optimal absorption.

Q: What is the difference between isotonic, hypotonic, and hypertonic drinks?
A: Isotonic: same osmolality as blood, balanced fluid and energy replacement (most sports drinks). Hypotonic: lower osmolality, faster fluid absorption, less energy (e.g., diluted juice). Hypertonic: higher osmolality, more energy but slower absorption (e.g., fruit juice, recovery drinks).

Q: What is collagen protein and is it beneficial for athletes?
A: Collagen is the most abundant protein in the body, found in tendons, ligaments, skin, and cartilage. Supplementing with 10–15 g collagen peptides + vitamin C before exercise may support tendon and ligament health. However, it is not a complete protein and should not replace whey/casein.

Q: What is the role of potassium in athletic performance?
A: Potassium helps regulate fluid balance, muscle contractions, and nerve signals. It works with sodium to maintain cellular hydration. Deficiency can cause muscle cramps and weakness. Athletes need 3500–4700 mg/day from foods like bananas, potatoes, spinach, and avocados.

Q: Is plant-based protein as effective as animal protein for athletes?
A: Plant proteins can be equally effective if consumed in sufficient quantity and variety to provide all essential amino acids. Plant proteins are generally lower in leucine and may have lower digestibility (DIAAS). Combining sources (e.g., rice + pea protein) creates a complete amino acid profile.

Q: What is the thermic effect of exercise (TEE)?
A: TEE is the energy expended during physical activity, including both structured exercise and non-exercise activity thermogenesis (NEAT). It is the most variable component of daily energy expenditure, ranging from 15–30% of TDEE depending on activity level.

Q: What should athletes eat for breakfast?
A: An ideal athletic breakfast includes protein (eggs, Greek yogurt, protein shake), complex carbs (oats, whole grain toast), and healthy fats (nuts, avocado). Example: 3-egg omelet with vegetables, oatmeal with berries, and a glass of milk (~600–800 kcal, 40 g protein).

Q: What is the role of insulin in nutrient partitioning?
A: Insulin is an anabolic hormone released in response to carbohydrate and protein intake. It promotes glucose uptake into muscle cells, stimulates glycogen synthesis, enhances amino acid uptake, and inhibits protein breakdown. Post-exercise, it helps shuttle nutrients to recovering muscles.

Q: How does training status affect nutrition needs?
A: Beginners can build muscle in a deficit (body recomposition). Intermediate athletes need a slight surplus for muscle gain. Advanced athletes need precise nutrition with small surpluses. Training status also affects glycogen utilization efficiency and fat oxidation capacity.

Q: What is the best nutrition strategy for weight-class sports?
A: Athletes in weight-class sports should minimize weight-cutting and compete as close to natural weight as possible. If cutting: lose weight gradually (0.5–1 kg/week), maintain high protein, use moderate water/sodium manipulation in final days. Rapid weight cuts impair performance and health.

Q: What nutrition is optimal for team sports (e.g., soccer, basketball)?
A: Team sports require 5–7 g carbs/kg/day, 1.4–1.7 g protein/kg/day, with emphasis on pre-game carb loading and halftime refueling. Hydration is critical as games involve intermittent high-intensity efforts. Post-game recovery should focus on protein + carbs within 2 hours.

Q: What is the best nutrition for swimming?
A: Swimmers need high carbohydrate intake (6–10 g/kg/day) due to high training volumes. Pool chlorine increases oxidative stress, so antioxidant-rich foods are beneficial. Meals should be timed 2–3 hours before training. Recovery nutrition is critical due to multiple daily sessions.

Q: How should runners fuel for a marathon?
A: Marathon nutrition involves: carb loading (8–12 g/kg) for 2–3 days pre-race, a familiar pre-race meal 3–4 hours before, consuming 30–60 g carbs/hour during the race via gels/drinks, and aggressive post-race recovery with protein + carbs + electrolytes.

Q: What is the importance of gut training for athletes?
A: Gut training involves practicing race-day nutrition during training to improve gastrointestinal tolerance and nutrient absorption. The gut can be trained to absorb more carbohydrate (up to 90 g/hour) and tolerate foods during exercise with consistent practice.

Q: What are the nutritional needs of masters athletes (over 40)?
A: Masters athletes need higher protein (1.6–2.2 g/kg/day) due to anabolic resistance, adequate vitamin D and calcium for bone health, omega-3s for inflammation management, and may benefit from creatine supplementation. Recovery takes longer, so post-workout nutrition timing is more important.

Q: What is the role of probiotics in sports nutrition?
A: Probiotics are beneficial bacteria that support gut health and immune function. For athletes, they may reduce upper respiratory tract infections, improve GI symptoms during exercise, and support nutrient absorption. Strains like Lactobacillus and Bifidobacterium are most studied.

Q: What is the myth about eating fat making you fat?
A: This is false. Fat gain is caused by a caloric surplus, regardless of macronutrient source. Dietary fat is essential for hormones, cell membranes, and vitamin absorption. Healthy fats (avocados, nuts, olive oil) should comprise 20–35% of calories.

Q: Is the myth 'you must eat every 2–3 hours to boost metabolism' true?
A: This is largely a myth. Meal frequency has minimal impact on metabolic rate when total calorie and protein intake are equated. The thermic effect of food is determined by total intake, not meal frequency. Eating 3–6 meals per day based on preference and schedule is fine.

Q: Does eating carbs at night cause fat gain?
A: No. Total daily calorie intake, not timing, determines fat gain. Carbs at night can actually improve sleep quality (via serotonin/melatonin production) and may be beneficial for morning training. What matters is the overall energy balance throughout the day.

Q: Is detoxing or cleansing necessary for athletes?
A: No. The liver, kidneys, and digestive system already detoxify the body effectively. Juice cleanses and detox diets are unnecessary, often lack protein and calories, and can impair performance and recovery. A balanced, whole-foods diet supports natural detoxification.

Q: Do you need supplements to build muscle?
A: No. Supplements are not required for muscle building. A well-planned diet can provide all necessary nutrients. However, creatine, protein powder, and vitamin D may be convenient and beneficial when dietary intake is insufficient. Supplements should supplement, not replace, real food.