120g/h of gels, chews, or sports drink? (#362)

In the past 10–15 years, the recommendations for energy intake during prolonged physical activity have been at 90 g of carbohydrates per hour. However, in recent years, that limit has begun to be pushed upwards. Consuming 100 g and even 120 g/h has become increasingly common. These new recommendations mostly come from individual case studies, athletes, and coaches. There are some studies, but they vary in design. Notably, there are differences in how competition-like the tests were and what type of carbohydrate mix was used. Many studies are still conducted on nutrition products with a 2:1 carbohydrate ratio instead of 1:0.8, which several studies have shown to be the most effective ratio.

Need a reminder of why carbohydrate ratio is so crucial in sports nutrition? Check out this article by Tommy.

To ingest 120+ grams of carbohydrates per hour, athletes use a variety of products: sports drinks, bars, gels, and chewables (candies). Chewables or jelly chews are often gummy candy-like pieces. They essentially contain the same carbohydrates as gels but in solid form. Developments in the food industry have made it possible to produce these while keeping protein, fat, and fiber content low, which reduces the risk of stomach issues that are more common with products like bars.

Previous studies have shown that sports drinks, gels, and chewables are absorbed at a similar rate, but these tests used a 2:1-ratio and around 90–100 g/h. However, if you push the intake up to 120 g and use the 1:0.8-ratio — which intake form is best then? And can athletes' guts handle this in a competitive scenario? This is what the study below has investigated.

13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or co-ingestion is its name, and it is from 2022. They examined the intake of 120 g of carbohydrates/h from sports drinks, gels, and chewables (jelly chew).

To ensure the study was as sports-specific as possible, nine voluntarily endurance-trained elite athletes were chosen (age 25 ± 8 years; weight 75.6 ± 7.0 kg; height 179.1 ± 4.7 cm). VO2max, peak power output (PPO), and power output at the ventilatory threshold were recorded as 64.9 ± 6.8 mL·kg−1·min−1, 438 ± 79 W, and 226 ± 37 W, respectively.

The study used a randomized crossover design, meaning all participants tested every energy product. Additionally, they assessed a mixed intake and a water-only intake. Participants were required to perform a 180-minute submaximal cycling test at 95% of LT1 (215 ± 35 W = conversational pace). This was followed by a capacity test at 150% of LT1 (339 ± 55 W). The test was repeated five times, with at least a seven-day interval between each test. The first test was conducted with water only. In the next four tests, participants ingested 120 g/h of carbohydrates in a 1:0.8 ratio from either a sports drink, gel, chewable (chew), or a combination of all three. Intake happened every 20 minutes with 40 g of carbs each time. During all tests, they consumed the same amount of fluid. 24 hours before testing, they ate a predetermined meal plan designed to provide 8 g of carbohydrates per kg body weight. Three hours before the test, a pre-exercise meal with 2 g of carbohydrates per kg body weight was consumed. The diagram below outlines the test setup. To measure carbohydrate utilization (oxidation), the energy products were enriched with traceable isotopes for glucose and fructose.

The three different energy products delivered very similar results. Heart rate and RPE showed no significant differences. As expected, RPE was higher during cycling conducted on water alone. Heart rate drift and VO2 increased across all tests.

Carbohydrate oxidation gradually decreased during the subject's endurance test, as expected. It was lowest during the water test, where fat oxidation was also higher—reasonable since no carbohydrates were provided.

There was no significant difference in the oxidation of ingested (external) carbohydrates during hours 2 and 3. Similarly, there was no notable difference in oxidation efficiency among Drink, Gel, Chew, or Mix (DRINK 72 ± 8 %, GEL 72 ± 5 %, CHEW 75 ± 4.6 %, MIX 75 ± 6 %; treatment effect, P = 0.179). The peak oxidation rate of external carbohydrates also showed no difference between groups (DRINK 1.56 ± 0.16, GEL 1.58 ± 0.13, CHEW 1.59 ± 0.08, MIX 1.66 ± 0.02 g·min−1; treatment effect, P = 0.189). It was noted that during tests with water, the utilization of the body's stored carbohydrate reserves was significantly greater.

The participants regularly (every 30 minutes) rated their experience of different gut symptoms on a scale from 0 to 10 (0 meaning no gut problems and 10 indicating very severe gut problems). On average, they reported a score of less than 2. This suggests that the energy intake was effective from a metabolic standpoint. Regarding performance during the capacity test, the results were also positive: a carbohydrate intake of 120 g/h enhanced performance compared to just water intake. As anticipated, there were no significant differences between the various carbohydrate types.

It's no "breaking news" that carbohydrate intake during activity enhances and sustains performance, but the high oxidation rate stands out. Up to 1.66 g/min for MIX. This, combined with minimal gut issues, provides more support for increasing carbohydrate intake recommendations from 90 g/h to up to 120 g/h during endurance activities at intensities around the first ventilatory threshold, or zone 3 intensity.

What makes this study exceptionally good and interesting is that all tests were conducted with the same carbohydrate ratio of 1:0.8. It could have been even more relevant for athletes if the test cyclists had ridden at an even higher intensity or a more varied intensity to simulate competition. It's also clear from the results that as long as you choose products with the right carbohydrate ratio and those with minimal fibers, fats, and proteins, it doesn't really matter if you go with gels, sports drinks, chews, or mix up your intake.

Previous studies, for instance, have shown that when consuming bars (which generally contain a bit more fat and fibers), oxidation peaked at 1.25 g/min while the risk of gut issues was higher.

The future of energy intake and energy planning likely points towards higher intakes but also smarter and more individualized plans based on oxidation rate, intensity, and type of sport. If you want to step up to 120 g/h—start gradually, test during training, and match products to your gut, intensity, and taste. We're happy to coach you along the way.