Diet & Exercise 4 — Questions and Answers
Question 1: What does the term 'energy availability' mean in sports nutrition?
- The total calories consumed in a day
- Dietary energy remaining after subtracting exercise energy expenditure, relative to lean body mass (Correct answer)
- The glycogen stored in muscles before exercise
- Calorie surplus needed for weight gain
Correct answer: Dietary energy remaining after subtracting exercise energy expenditure, relative to lean body mass
Energy availability = (dietary intake − exercise energy cost) ÷ fat-free mass; low energy availability can impair hormonal and metabolic function.
Question 2: Relative Energy Deficiency in Sport (RED-S) is most commonly triggered by which scenario?
- Eating too much protein
- Chronic low energy availability relative to training demands (Correct answer)
- Taking creatine supplements
- Overhydration during competition
Correct answer: Chronic low energy availability relative to training demands
RED-S occurs when athletes do not consume enough calories to support both exercise and normal physiological functions, affecting hormones, bone, and immunity.
Question 3: Which macronutrient has the highest thermic effect of food (TEF), meaning the body burns the most calories digesting it?
- Fat
- Carbohydrates
- Protein (Correct answer)
- Alcohol
Correct answer: Protein
Protein has a TEF of approximately 20–35%, compared to 5–15% for carbohydrates and 0–3% for fat, making it the most metabolically costly macronutrient to digest.
Question 4: A marathon runner 'hitting the wall' around mile 20 is primarily experiencing what physiological event?
- Dehydration causing muscle cramps
- Complete depletion of liver and muscle glycogen stores (Correct answer)
- Protein breakdown reaching a critical threshold
- Blood pressure dropping dangerously low
Correct answer: Complete depletion of liver and muscle glycogen stores
Glycogen depletion forces the body to rely almost entirely on fat for fuel, which cannot sustain race pace, causing the dramatic slowdown known as 'hitting the wall.'
Question 5: Which supplement has the strongest evidence for improving high-intensity exercise performance and is approved by major sports organizations?
- Glutamine
- BCAAs alone
- Creatine monohydrate (Correct answer)
- Collagen peptides
Correct answer: Creatine monohydrate
Creatine monohydrate is one of the most extensively studied and effective supplements for increasing power output and muscle mass during resistance and high-intensity training.
Question 6: How does exercise-induced sweating affect dietary electrolyte needs?
- It has no impact on electrolyte needs
- It significantly increases needs for sodium, potassium, and magnesium (Correct answer)
- It only increases the need for calcium
- It reduces the need for all electrolytes
Correct answer: It significantly increases needs for sodium, potassium, and magnesium
Sweat contains electrolytes, particularly sodium, and prolonged exercise increases the need to replenish sodium, potassium, and magnesium to maintain fluid balance and muscle function.
Question 7: Which dietary approach is most appropriate for an athlete needing to lose body fat while maintaining training performance?
- A 1,000 kcal/day deficit regardless of training load
- A modest 300–500 kcal/day deficit with high protein and periodized carbohydrates (Correct answer)
- Complete elimination of carbohydrates
- Alternating between binging and severe restriction weekly
Correct answer: A modest 300–500 kcal/day deficit with high protein and periodized carbohydrates
A modest deficit paired with high protein and adjusted carbohydrate intake allows gradual fat loss while preserving muscle mass and supporting training quality.
Diet & Exercise 4
What does the term 'energy availability' mean in sports nutrition?