A systematic review and meta-analysis of carbohydrate benefits associated with randomized controlled competition-based performance trials

Abstract

BackgroundCarbohydrate supplements are widely used by athletes as an ergogenic aid before and during sports events. The present systematic review and meta-analysis aimed at synthesizing all available data from randomized controlled trials performed under real-life conditions.MethodsMEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched systematically up to February 2015. Study groups were categorized according to test mode and type of performance measurement. Subgroup analyses were done with reference to exercise duration and range of carbohydrate concentration. Random effects and fixed effect meta-analyses were performed using the Software package by the Cochrane Collaboration Review Manager 5.3.ResultsTwenty-four randomized controlled trials met the objectives and were included in the present systematic review, 16 of which provided data for meta-analyses. Carbohydrate supplementations were associated with a significantly shorter exercise time in groups performing submaximal exercise followed by a time trial [mean difference −0.9 min (95 % confidence interval −1.7, −0.2), p = 0.02] as compared to controls. Subgroup analysis showed that improvements were specific for studies administering a concentration of carbohydrates between 6 and 8 % [mean difference −1.0 min (95 % confidence interval −1.9, −0.0), p = 0.04]. Concerning groups with submaximal exercise followed by a time trial measuring power accomplished within a fixed time or distance, mean power output was significantly higher following carbohydrate load (mean difference 20.2 W (95 % confidence interval 9.0, 31.5), p = 0.0004]. Likewise, mean power output was significantly increased following carbohydrate intervention in groups with time trial measuring power within a fixed time or distance (mean difference 8.1 W (95 % confidence interval 0.5, 15.7) p = 0.04].ConclusionDue to the limitations of this systematic review, results can only be applied to a subset of athletes (trained male cyclists). For those, we could observe a potential ergogenic benefit of carbohydrate supplementation especially in a concentration range between 6 and 8 % when exercising longer than 90 min.Electronic supplementary materialThe online version of this article (doi:10.1186/s12970-016-0139-6) contains supplementary material, which is available to authorized users.

Optimal Nutrition for Endurance Exercise: A Systematic Review

“…There was no difference between the oat flour and the control groups. Among trained male cyclists, a recent systematic review and meta-analysis focused on carbohydrate supplementation immediately before and during endurance exercise found a reduction in time to cycle a fixed distance after steady state cycling and in mean power output with carbohydrate containing beverages compared to placebo [20]. This effect was most evident in beverages with a 6 and 8% carbohydrate concentration and exercise lasting greater than 90 mins.…”

“…During endurance events lasting longer than 1.5-2 hours, carbohydrates have consistently provided ergogenic benefit compared to fat and protein [20,23]. While CHO has historically been the primary fuel source during long, moderate-intensity endurance events, various studies have also suggested a threshold exists to exogenous carbohydrate oxidation during exercise.…”

“…Previous research has led to recommendations of CHO as the primary fuel source for optimal performance during endurance exercise longer than 1 hour [23]. A recent meta-analysis revealed pool effect sizes that favored CHO ingestion compared to water-only across all performance-based tests [20].…”

Investigation of the Effect of Free Sugar Consumption on Oral and Dental Health in Athletes

“…Literatürde karbonhidrat tüketiminin spor performansına ve toparlanmaya olumlu katkı sağladığı, tüketilen karbonhidratın çeşidi ve zamanlamasının önemli olduğu, özellikle antrenman içerisinde ve antrenmandan hemen sonra ilk 15 dk ile ilk 2 saatte basit şeker tüketiminin toparlanmaya olumlu katkı sağladığı bildirilmektedir. 18 Çalışmamızda da basit şeker tüketimi fazla olan sporcuların yağsız vücut kütlesi ve kas kütlesinin diğer gruba göre daha fazla olmasını; doğru karbonhidrat çeşidinin doğru zamanda tüketilmesiyle birlikte sporcuların daha iyi antrene olabilmelerine ve antrenman sonrası toparlanmanın daha iyi olmasına bağlamak mümkündür. Ancak basit şeker tüketiminin vücut kompozisyonu üzerine etkilerini araştıracak ileri çalışmalara ihtiyaç olduğunu düşünmekteyiz.…”

The Effect of Ergogenic Supplements and Mediterranean Diet on Cycling Performance. Differences According to Duration and Intensity.

“…The main nutrient that can improve endurance and reduce fatigue is carbohydrates [20,72], through maintaining blood glucose levels, CHO oxidation rates and preventing glycogen depletion [13]. Athletes consuming high proportion of carbohydrates had a better performance compared to others who consumed moderate quantities [14,16,38].…”