49. HOW MANY CARBS DURING EXERCISE? MORE IS NOT (ALWAYS) BETTER
In a previous KisW Research Note, we saw that ingesting 120 vs 90 g/h of carbs during exercise with a 0.8:1 glucose:fructose ratio do not make spare any additional endogenous carbs (glycogen) during a 3 hours ride in high zone 2 (~250 W for the amateur cyclists in that study). So, it is very likely that even performance will be not enhanced by 120 g/h vs 90 g/h in a similar scenario. However, it is always better to have a look at the data.
Does ingesting more than 90 g/h of carbs increase performance at the end of a long ride?
A study published by King and Colleagues from Leeds Beckett University (UK) on Physiological Reports in 2018 tried to answer this question. (1)
WHAT DID THEY DO?
They recruited ten trained males amateur cyclists.
In a randomized order, on 5 different days and conditions, they rode for 2h at 77% VO2max (read high zone 2 or low zone 3 in a 5/7 zones model), followed by a 30‐min time‐trial (TT).
The 5 conditions differed for the amounts and types of carbs ingested during the 2hrs ride:
0 g/h
60 g/h only glucose
75 g/h only glucose
90 g/h glucose+fructose (2:1 ratio, so 60g glucose and 30g fructose)
112.5 g/h glucose+fructose (2:1 ratio, so 75g glucose and 37.5g fructose)
WHAT DID THEY FIND?
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