I appreciate that I must sound like a broken record when I say that carbs are absolute king for performance… but, they are.
In this week’s Dedication to Education Wednesday, I’ve got a fresh off the press study to show you just how significant having the right amount of carbs can make to your performance.
Hearris et al (2019) got a group of fellas to test how three different carb intakes impact their performance. So, here’s what they did:
Phase 1: Glycogen Depletion.
The participants followed a standardized high carb diet of 8g/kg (640g for an 80kg guy) before performing an evening glycogen depletion session on a stationary bike. The aim of this training session was to hit complete exhaustion to deplete muscle glycogen so they entered the 2nd phase under the same circumstances, i.e. depleted.
Phase 2: Carb Refeeding Strategy.
The group of men got split into one of three groups’ dependent on the amount of carbs they’ll be eating that evening before they went to bed – for relatability, we’ll use the same 80kg guy as an example:
1) High carb = 1.2g/kg/hour of carbs for 3 hours followed by a large carb meal of 4g/kg (608g in total)
2) Medium carb = 1.2g/kg/hour of carbs for 3 hours without the high carb meal (288g in total)
3) Low carb = 0g of carbs after exercise (0g in total).
Phase 3: The Test.
The following morning, the three groups of fellas returned to the gym. Each group had different starting glycogen levels which meant performance can be attributed to their starting glycogen status. After performing 8 x 3 min intervals at 80%, they rested for 5 mins and did another interval sessions (1 min on, 1 min off) until they hit complete exhaustion.
The Results:
The aim of this test was to measure how long they lasted on the bike before they were completely exhausted when riding at the same intensity (80% peak power output).
High carb = 44 mins.
Medium carb = 36 mins.
Low carb = 18 mins (6 of 8 cyclists were unable to finish).
So, as we can blatantly see, starting a session, race or game with low glycogen levels is going to massively hinder your performance. You could be putting in exactly the same effort as your well fueled counterpart, but it’s your eating that is compromising your ability to perform.
Looking at these results, these cyclists lasted ~26 minutes longer by simply eating more carbs.
F#cking bananas!