This week, we are looking at a study on personalized carbohydrate intake during long training sessions and races.  The researchers examined whether athletes can achieve the same carbohydrate oxidation with less intake by tailoring fueling to individual physiology.

This has implications for performance, gut comfort, and how you use Speed Nectar in training and competition.

Carbs help maintain blood glucose, support high work rates, and delay fatigue.  Current guidelines usually recommend broad intake ranges based on session length, such as 60g to 90g per hour. 

However, research shows that athletes differ in how efficiently they absorb and use carbohydrate.  The authors stated that their objective was “to determine whether exogenous glucose oxidation rates achieved with a high glucose dose could inform a personalized glucose dose that maintains comparable oxidation with reduced intake”.

Eleven trained endurance athletes completed two 150min cycling sessions.  In one trial, they consumed 90g/h of glucose.  In the other, they used a personalized dose based on their measured oxidation rates.

On average, intake was reduced by about 28%, to around 65g/h.  Despite this, glucose use and blood markers were almost identical between trials.  Athletes also reported lower perceived effort and less stomach fullness with the personalized approach.

This study suggests that more is not always better when it comes to fueling.

For some athletes, forcing very high carbohydrate intakes may be unnecessary and uncomfortable. A slightly lower, well-tested intake may provide the same performance benefit with better tolerance.