I’ve been a long time fanboy of Trainer Road ( since 2012 ) and have generally accepted their advice carte blanche. I’ve followed the podcast through the years of recommending higher and higher on-bike carbs and worked my gut up to handling ~110g/hour.
Then I came across this new study, which was just published:
Which says, at 70% VO2max ( a bit below FTP ) with only 10g of carbs per hour, there is no performance difference between people adapted to a high carb diet, or people adapted to a low carb- high fat diet.
Has this been discussed elsewhere? Would love to hear the coaches dissect this on an episode of the podcast.
PS. Apologies if I’ve missed this being posted elsewhere. A brief search for “Noakes” ( the author ) didn’t bring up anything relevant.
For what I quickly see they talk about a single 90min or so effort till TTE.
You muscles energy storages are big enough to handle that, especially if you rested the days before the efforts. So not very surprising result.
But that’s not what any racer does, who trains daily with a high energy demand. So imo not much to conclude from it.
But maybe I missed something…
A few years ago, I lost a lot of weight going low carb. I have a terrible sweet tooth and can pretty much eat as much sugar as you put in front of me, so this really helped with weightloss.
Having said that, I was fine doing Tempo and below, but once I tried to get into Threshold and above, I didn’t have much in me for longer efforts. I could handle something like 30/30s, but 4x4 @ VO2 was extremely painful.
RPE was up considerably in all zones, even Z2. Once I went back to sugar, RPE dropped and I was absolutely able to do more hard work.
Note: this may have also been at least partially due to general fatigue from running a calorie deficit, but I can definitely say that hard work is easier with sugar in my bottle.
Yes. We were talking about it ad nauseum last week.
Ingestion of carbohydrate during time trial resulted in statistically significant improvement of performance. That was for very, very modest carbohydrate consumption. I would have said that was consistent with what TR has advocated. I say if the study had used more carbohydrate then the difference would only have been bigger, but we can’t say from this study. MORE RESEARCH IS REQUIRED! (always, more research is required)
I think the thing that most people are surprised by is that time to exhaustion in a Time Trial, CHO bolus, Time Trial arrangement, LCHF performs the same as HCLF. Most would expect HCLF to outperform. But I’m not surprised. This has been tangentially discussed on other podcasts. Fat adaptation doesn’t impact glycogen storage or result in glycogen sparing at higher intensities.
This is a really fun paper to kick around/talk/debate, though.
I don’t do triathlons so maybe it’s different, but I don’t think I could find a single racing in my entire racing career where I was only doing 70% of my VO2 max power. Yes, for long road races, I might average that over the entire race, but I’m doing lots of efforts much higher than that, not to mention any final pushes near the finish. For crits, CX, MTB I’ll probably average that for the race and not spend much time below. So it doesn’t really translate much to any real world riding I’m doing.
That and it doesn’t touch day after day efforts like stage races or even back to back training days.
Tim Noakes has done some good work in the past, but he’s gone off the rails a time or two in the past 10 years so it’s tough for me to trust anything that comes out of his mouth or lab
(always, more research is required)