Nutrient timing, strategic meal timing around training and competition, adds another level of precision to your training. Nutrient timing requires planning and testing whole or enriched foods and supplements around activity or competitions to dial in what benefits you. You need to establish how much of which macronutrients are consumed at which time periods before, during, and post activity to improve performance, recovery, and adaptation.
Macronutrient timing and ratio planning are specific to the athlete, there is no one recommendation. Science-backed information suggests guidelines for timing the ingestion of carbohydrates (CHO), protein (PRO), and fat. Other variables such as the duration of activity, type (resistance training vs endurance), and intensity are key factors in timing and planning consuming nutrients. In this blog, we will cover the recommended consumption and benefits of these macronutrients pre-exercise, during exercise, and post.
The Role of Carbohydrates
You may know that carbohydrate loading before activity is one of the oldest and most effective nutrient timing practices. When carbs are consumed, the body’s blood sugar levels rise significantly, prompting the pancreas to release insulin. This hormone moderates the output of glucose from the liver and prompts the movement of glucose into muscle cells. Any unnecessary glucose is converted into glycogen and stored. These glycogen stores are a crucial energy source during physical activity.
Pre-Exercise
The availability of glycogen, influenced by nutritional status, athlete training level, and exercise intensity, is limited. During moderate to high-intensity exercise (65 – 85% VO2 max), endogenous glycogen stores may only be sustained for 90 minutes to 3 hours.
Diminishing glycogen levels are linked to reduced exercise intensity, pace, and work output (Coyle EF, Coggan AR, Hemmert MK, Lowe RC, Walters TJ. Substrate usage during prolonged exercise following a preexercise meal. J Appl Physiol.1985). The depletion of glycogen is associated with heightened muscle tissue breakdown and suppression of the immune system.
Optimal promotion of maximal endogenous glycogen stores is achieved through adherence to a high-glycemic, high-carbohydrate diet (600 – 1000 grams or approximately 8 – 10 g/kg/day).
Daily CHO intake for athletes training or competing at moderate to high-intensity levels (65 – 85% VO2 max) is recommended to consume 65% CHO to maintain muscle glycogen.
5 to 7 days before competition, we recommend you increase CHO consumption to roughly 70% to maximize muscle and living glycogen stores and ultimately sustain blood glucose throughout exercise. This could also be achieved after just 1 to 3 days of consuming a high-CHO diet while minimizing physical activity.
It is recommended to ingest carbohydrates one hour prior to exercise to maximize glycogen utilization and promote oxidation to sustain performance during exercise.
During Exercise
Studies indicate that pre-exercise ingestion of carbohydrates improves performance only when CHO ingestion is maintained throughout exercise. (Febbraio MA, Chiu A, Angus DJ, Arkinstall MJ, Hawley JA. Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance. J Appl Physiol. 2000).
CHO availability and muscle glycogen levels significantly impact endurance performance, especially when glycogen is low at exercise onset.
Beyond 60 minutes of exercise, exogenous CHO sources become crucial for maintaining blood glucose and muscle glycogen. Recommended intake is 30–60 grams of CHO per hour, achievable through 1–2 cups of a 6–8% CHO solution (8–16 fluid ounces) every 10–15 minutes.
Combining different CHO forms enhances muscle CHO oxidation, improving time trial performance [50,52-54]. We recommend you avoid large amounts of fructose to minimize gastrointestinal issues.
Post Exercise
Consuming high doses of CHO post-exercise (within 30 minutes) at 8–10 g CHO/kg/day stimulates muscle glycogen resynthesis.
Enhancing glycogen resynthesis is achieved by adding PRO (0.2–0.5 g PRO/kg/day) to CHO in a ratio of approximately 3:1 (CHO:PRO).
The Role of Protein and Essential Amino Acids
Protein plays a crucial role in muscle protein synthesis, influencing the breakdown and synthesis of proteins in your body. Research has shown that ingesting protein, especially essential amino acids, either alone or in combination with carbohydrates (CHO), can significantly impact the net protein status, particularly when consumed before resistance exercise. This suggests that protein intake when strategically timed, may enhance training adaptations to resistance exercise by promoting protein synthesis.
Pre-Exercise
Research indicates that pre-exercise supplementation with whey protein and leucine can lead to greater increases in maximal strength during unilateral resistance training (Coburn JW, Housh DJ, Housh TJ, Malek MH, Beck TW, Cramer JT, Johnson GO, Donlin PE. Effects of leucine and whey protein supplementation during eight weeks of unilateral resistance training. J Strength Cond Res. 2006.)
Incorporating protein into the pre-exercise routine in a 3-4:1 ratio (CHO:PRO) with carbohydrates has shown a significant increase in endurance performance during both immediate and subsequent bouts of exercise
Participants in a study ingested either 20g of protein (14g whey and casein protein + 6g free amino acids) or 20g of carbohydrates before and after each exercise session, totaling 40g/day of protein or 40g/day of carbohydrates. Those consuming the protein supplement exhibited significant improvements in body mass, fat-free mass, strength, serum levels, intramuscular levels, and myofibrillar protein content. (Study: Willoughby DS, Stout JR, Wilborn CD. Effects of resistance training and protein plus amino acid supplementation on muscle anabolic, mass, and strength. Amino Acids. 2007)
During Exercise
Adding PRO to CHO in a ratio of 3–4:1 (CHO:PRO) enhances endurance performance in both acute and subsequent bouts of endurance exercise
Ingesting CHO alone or with PRO during resistance exercise increases muscle glycogen, offsets muscle damage, and promotes greater training adaptations after both acute and prolonged resistance training periods
A study by Saunders et al. showed the impact of combining carbohydrates (CHO) and protein (PRO) on performance and muscle damage. A group of cyclists underwent two exhaustive sessions, consuming either a 7.3% CHO solution or a 7.3% CHO/1.8% PRO solution every 15 minutes during and after exercise. The CHO + PRO group showed a 29% performance increase after the first bout and a 40% increase after the second, compared to CHO-only. Post-exercise, muscle damage markers were 83% lower in the CHO + PRO group, indicating effective attenuation of exercise-induced muscle damage.
Post-Exercise
Amino acids, particularly essential amino acids (EAAs), ingested post-exercise (immediately to 3 hours post) robustly stimulate muscle protein synthesis [73,74,83]. The addition of CHO may further increase protein synthesis, with pre-exercise consumption yielding the best response
Post-exercise consumption of varying amounts of CHO + PRO supplements during prolonged resistance training stimulates improvements in strength and body composition compared to control, placebo, or CHO-only conditions
Adding Cr (0.1 g Cr/kg/day) to a CHO + PRO supplement may enhance adaptations to resistance training
The Role of Fats
There is limited reliable data on the impact on performance of fats. There is a misconception that fat oxidation impacts endurance performance more effectively than carbohydrates. Studies comparing carbohydrates and ketone-fueled performances actually indicate an advantage for carbohydrates. Significant bodies of research indicate increased fat oxidation can lead to decreased exercise economy and higher performance costs. High-fat, low-carb diets show no improvement and diminish the benefits of supplemental carbohydrates during exercise.
Conclusion
Optimizing nutrient timing, and the strategic intake of carbohydrates and protein, can be a game-changer for athletes striving for peak performance. Carbohydrates play a pivotal role in endurance-based activities that require tailored intake recommendations based on exercise duration and intensity. Combining carbohydrates with protein, particularly in a 3:1 ratio, not only enhances glycogen resynthesis but also promotes muscle protein synthesis, leading to improved strength and body composition. The study by Saunders et al. exemplifies the profound impact of this combination, showcasing significant performance increases and reduced muscle damage. Whether it’s carbohydrate loading before activity, ingesting amino acids post-exercise, or adding creatine to a carbohydrate-protein supplement, the personalized timing and ratio of macronutrients play a crucial role in achieving optimal athletic outcomes.