Sport Nutrition Timing Calculator
Nutrient timing refers to the strategic intake of food and fluid relative to training sessions to optimise performance, recovery, and adaptation. While overall daily nutrient intake is the primary driver of athletic performance, what you eat and when you eat it around training can meaningfully affect the quality of the session and the speed of recovery. This calculator generates personalised pre-workout, intra-workout, and post-workout carbohydrate, protein, and fluid targets based on your body weight and session duration, following the evidence-based guidelines from the ACSM and the Academy of Nutrition and Dietetics.
Nutrition timing formula (ACSM/AND/DC)
Pre-workout carbs = BW x 1.0-2.0 g/kg (1-4hr before)
Intra-workout carbs: <60min=0g/hr, 60-90min=30-60g/hr, >90min=60-90g/hr
Post-workout carbs = BW x 1.0-1.5 g/kg (within 30min)
Post-workout protein = BW x 0.25-0.3 g/kg (20-40g target)
Pre-workout fluid = BW x 5-7 ml/kg (4hr before)
Intra-workout fluid = 400-800 ml/hr (sweat-rate dependent)
Frequently asked questions
When should I eat before training?
ACSM and Academy of Nutrition and Dietetics guidelines recommend a meal containing 1 to 4 g of carbohydrates per kg body weight consumed 1 to 4 hours before exercise. A smaller snack (0.5 to 1 g/kg) 30 to 60 minutes before training is appropriate if a larger meal cannot be timed optimally.
Do I need to eat during training?
For sessions under 60 minutes at moderate intensity, no intra-workout nutrition is needed. For sessions of 60 to 90 minutes, 30 to 60 g of carbohydrate per hour is recommended. For sessions over 90 minutes, 60 to 90 g of carbohydrate per hour (from multiple sources) optimises performance.
What should I eat after training?
The ACSM recommends consuming 1.0 to 1.5 g of carbohydrate per kg body weight within 30 minutes after exercise for glycogen resynthesis, combined with 0.25 to 0.3 g of protein per kg body weight (approximately 20 to 40 g) to stimulate muscle protein synthesis.
Does the anabolic window really exist?
Post-exercise nutrition timing matters more for athletes training in a fasted state or who train twice daily. For most athletes who eat adequate protein across the day, the so-called anabolic window is less critical. However, consuming protein within 2 hours of training is still beneficial for muscle protein synthesis rates.
How much fluid do I need around training?
ACSM guidelines recommend consuming 5 to 7 ml of fluid per kg body weight 4 hours before exercise, and replacing 150% of sweat losses (weigh before and after training) within 4 to 6 hours post-exercise. During exercise, aim to prevent body weight loss exceeding 2% from sweat.
Official sources
- Academy of Nutrition and Dietetics / ACSM / Dietitians of Canada: Joint Position Statement: Nutrition and Athletic Performance.
- International Society of Sports Nutrition: ISSN Position Stand: Nutrient Timing.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.