Are Carbs Critical for Resistance Training, Endurance Training, and Recovery? If So, Why, and How Much Is Needed for Optimal Results?

January 24, 2025

The role of carbohydrates in athletic performance—particularly endurance activities—is well established. However, their significance in resistance training and post-exercise recovery, while equally essential, remains less widely recognized. Carbohydrates are metabolized into glycogen, the body’s preferred energy source for moderate-to-high-intensity exercise, which is stored in the liver and skeletal muscles. Notably, individuals with higher training statuses can accumulate greater glycogen stores.

In this article, we examine the latest research to define evidence-based carbohydrate intake recommendations for resistance training, endurance activities, and recovery.

Resistance Training

A key question in resistance training nutrition is whether additional carbohydrate supplementation is necessary beyond a regular diet. For sessions lasting less than 90 minutes per day, the answer is no—carbohydrate needs are typically met through a balanced diet (unless concurrent intense activity is performed the same day).

A recent systematic review evaluated the impact of carbohydrate intake within 24 hours prior to resistance training on performance outcomes (3). Approximately two-thirds of the included studies found no significant differences in performance, while the remaining third reported enhanced performance with higher carbohydrate intake. However, the review authors noted that the observed benefits in the latter group were likely attributable to increased overall caloric intake—rather than carbohydrate-specific effects—which promoted satiety and indirectly improved performance.

The authors further highlighted that a typical athlete maintains ~500 grams of muscle glycogen, and a standard one-hour resistance training session depletes only ~80 grams (or 16% of total muscle glycogen). Thus, adequate total caloric intake emerges as a more critical factor for resistance training performance than carbohydrate quantity alone.

Another researcher emphasized that resistance and power athletes do not require carbohydrate intakes as high as endurance athletes to maintain glycogen stores (2). A separate study found no differences in muscle mass or strength gains between high- and low-carbohydrate groups, though high-carbohydrate diets may confer minor advantages (Ribeiro).

For post-exercise nutrition, one study focused on strength athletes recommends consuming 1.2 g/kg of body mass (BM) of carbohydrates paired with 0.4 g/kg BM of protein within several hours of training (1). This can be easily achieved through a structured, whole-food meal and is substantially lower than guidelines for endurance athletes.

Endurance Training

In contrast to resistance training, endurance activities—defined as competitions exceeding 90 minutes, multiple daily events, or multi-day competitions—demand precise carbohydrate planning to optimize performance (4).

Training Status and Glycogen Stores

Training status is a key determinant of pre-exercise carbohydrate needs: untrained individuals typically store ~200 mmol/kg of muscle glycogen, while highly trained athletes can accumulate over 800 mmol/kg (5). Consequently, glycogen depletion occurs more rapidly in less-trained individuals, necessitating greater pre-exercise carbohydrate supplementation compared to their highly trained counterparts.

Pre-Exercise and During-Exercise Recommendations

To achieve muscle glycogen loading (maximizing stored energy), athletes are recommended to consume a very high-carbohydrate diet (10–12 g·kg⁻¹ BM) for 36–48 hours before competition (5).

During exercise lasting up to three hours, athletes should ingest up to 60 g per hour of rapidly digestible carbohydrates—such as glucose or glucose-fructose blends—to maintain energy availability (5).

Recovery/Post-Competition and Training

Carbohydrate strategies for recovery depend on four primary factors:

1. The interval until the next training session or competition

2. The type of exercise performed

3. Individual nutritional requirements

4. Training status (2)

The core goal of post-exercise carbohydrate intake is to replenish liver and muscle glycogen stores, which typically takes 24–36 hours for full restoration (5).

Evidence-Based Guidelines

• Rapid glycogen repletion (for next-day sessions): Athletes should prioritize carbohydrate intake as soon as possible post-exercise, at a rate of 1.0–1.2 g/kg BM per hour for the first four hours (5).

• Delayed recovery (≥2 days until next session): A standard balanced diet is sufficient (5).

Training status also influences recovery: individuals with higher training statuses—who can store more muscle glycogen—may benefit from higher carbohydrate doses than the standard recommendations (Podloger).

Daily Carbohydrate Needs by Training Intensity

The International Society of Sports Nutrition (ISSN) provides graded daily carbohydrate recommendations based on training volume and intensity:

• Moderate duration/low intensity (2–3 hours/day of intense exercise, 5–6 days/week): 5–8 g·kg⁻¹ BM·day⁻¹

• Moderate-to-heavy endurance training (3–6 hours/day of intense training in 1–2 sessions, 5–6 days/week): 8–10 g·kg⁻¹ BM·day⁻¹

• Extreme exercise/competition (>6 hours/day or high weekly competition frequency): 10–12+ g·kg⁻¹ BM·day⁻¹

Conclusion

Carbohydrates are fundamental to athletic performance, underpinning endurance energy metabolism, resistance training recovery, and adaptive processes.

• For resistance training sessions lasting <90 minutes, carbohydrate requirements are generally satisfied by a regular, balanced diet—with total caloric intake playing a more pivotal role in performance than carbohydrate quantity.

• For endurance athletes, targeted carbohydrate planning is essential to optimize glycogen stores—especially for extended or high-intensity efforts.

• Recovery strategies must be customized based on the interval between training sessions, the athlete’s training status, and individual nutritional needs.

By recognizing these differences, athletes can tailor carbohydrate intake to their specific goals, maximizing both performance and recovery.

References

• Bird SP, Nienhuis M, Biagioli B, De Pauw K, Meeusen R. Supplementation Strategies for Strength and Power Athletes: Carbohydrate, Protein, and Amino Acid Ingestion. Nutrients. 2024 Jun 14;16(12):1886. doi: 10.3390/nu16121886. PMID: 38931241; PMCID: PMC11206787.

• Bonilla DA, Pérez-Idárraga A, Odriozola-Martínez A, Kreider RB. The 4R's Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates. Int J Environ Res Public Health. 2020 Dec 25;18(1):103. doi: 10.3390/ijerph18010103. PMID: 33375691; PMCID: PMC7796021.

• Henselmans M, Bjørnsen T, Hedderman R, Vårvik FT. The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review. Nutrients. 2022 Feb 18;14(4):856. doi: 10.3390/nu14040856. PMID: 35215506; PMCID: PMC8878406.

• Kerksick C.M., Wilborn C.D., Roberts M.D., Smith-Ryan A., Kleiner S.M., Jäger R., Collins R., Cooke M., Davis J.N., Galvan E., et al. ISSN Exercise & Sports Nutrition Review Update: Research & Recommendations. J. Int. Soc. Sports Nutr. 2018;15 doi: 10.1186/s12970-018-0242-y.

• Podlogar T, Wallis GA. New Horizons in Carbohydrate Research and Application for Endurance Athletes. Sports Med. 2022 Dec;52(Suppl 1):5-23. doi: 10.1007/s40279-022-01757-1. Epub 2022 Sep 29. PMID: 36173597; PMCID: PMC9734239.