Nutrition in CrossFit® - scientific evidence and practical perspectives: a systematic scoping review

Abstract

Background: CrossFit^Ⓡ sessions and competitions are characterized by high-intensity challenges that combine aerobic and anaerobic activities with short recovery periods. As a result, effective nutritional practices play a crucial role in optimizing performance and enhancing recovery. Therefore, nutritional practices are central to optimizing performance and accelerating recovery. This review aims to summarize current evidence on nutritional and ergogenic aid responses to CrossFit^Ⓡ practice.

Methods: The search was conducted in four electronic databases (PubMed, Web of Science, Scopus and SportDiscus). Gray literature was also extracted for studies exploring the nutritional habits of CrossFit^Ⓡ participants as well as the ingestion of ergogenic aids. In addition, a meta-analysis was conducted to examine the impacts of dietary habits and ergogenic aids on performance.

Results: Forty-nine studies met the eligibility criteria and were included in the current review. Carbohydrate intake was below the recommendations for athletes, although protein ingestion remains adequate. High-carbohydrate diets had a positive effect on CrossFit^Ⓡ performance. The evidence concerning the effects of a ketogenic diet on performance is limited. When used prior to or during the workout, the impact of carbohydrates on CrossFit^Ⓡ performance was negligible, whereas the effect of caffeine was significant. Ergogenic aids, particularly creatine and protein, are commonly used by CrossFit^Ⓡ participants.

Conclusion: The standard diets recommended to CrossFit^Ⓡ participants need to be revised because they are characterized by lower values of carbohydrates. Caffeine should be used prior to or during the CrossFit^Ⓡ sessions. Regarding the impact of ergogenic aids on recovery, future studies are needed.

Keywords: Carbohydrates; caffeine; conditioning; energy; performance; strength.

Figure 1.

Flow chart of records identification, screening and inclusion in the present review articleCHO (carbohydrates).

Figure 2.

Mean energy intake of studies with CrossFit® participants.

Figure 3.

Mean CHO and protein intake of studies with CrossFit® participants.

Figure 4.

Mean values of energy intake and moving averages plot against the year of publication of the included studies (De Jesus et al. [34]; Rezende et al. [37]; Pearson and Jenkins [41]; gonçalves et al. [42]; Vieira et al. [45]; Gogojewicz et al [48]; Zaykova [49]).

Figure 5.

Mean values of CHO intake and moving averages plot against the year of publication of the included studies (De Jesus et al. [34]; Pearson and Jenkins [41]; gonçalves et al. [42]; Vieira et al. [45]; Gogojewicz et al. [48]; Zaykova [49]; Fayad [52]).

Figure 6.

Mean values of protein intake and moving averages plot against the year of publication of the included studies (De Jesus et al. [34]; Rezende et al. [37]; Pearson and Jenkins [41]; gonçalves et al. [42]; Vieira et al. [45]; Gogojewicz et al [48]; Zaykova [49]; Fayad [52]).

Figure 7.

Meta-analysis of the use of ergogenic aids among CrossFit® participants.

Figure 8.

Forest plot of effects of CrossFit® performance after the implementation of CHO or customary diets. The black diamond reflects the overall result.

Figure 9.

Forest plot of effects of CrossFit® performance considering CHO or placebo intake prior or during the workout. The black diamond reflects the overall result.

Figure 10.

Forest plot of effects of CrossFit® performance considering caffeine or placebo intake prior to the workout. The black diamond reflects the overall result.