Do carbs stop you from burning fat, why TSS doesn’t increase linearly, how to plan and recover from a training camp and more in Episode 266 of the Ask a Cycling Coach Podcast.
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I think the gel question didn’t really phrase what the “no early gels” rule was about, because there is some serious advice I’ve seen on this. I came across it on a podcast with Daniel Healey, former Head of Sports Science at Tinkoff Saxo (link).
The theory is that if you have a gel or other high glycaemic sugary carb before or very early on during a ride, it can cause a spike in insulin followed by rebound hypoglycaemia, making you feel tired, lethargic, or perhaps jittery. However once you start riding and do some hard efforts, catecholamines are released which inhibit insulin secretion and protect you from this effect.
That’s the theory anyway. It wasn’t really anything to do with how it affects fat oxidation for the rest of the ride. It may be there are holes in the theory, but for me the credibility of the source suggests it’s more than bro science.
Isn’t the long-standing rule to “eat before you’re hungry, drink before you’re thirsty”? And doesn’t exercise suppress insulin secretion anyway?
Also, if you really did experience an insulin spike, wouldn’t that reduce fatty acid levels and hence fat oxidation?
What I’m trying to say is that it sounds like pure BS (bro science) to me.
I think that’s the point Daniel Healey was making, and indeed I made - that until you start that exercise and it suppresses the secretion of insulin, you should avoid high sugar energy sources to avoid a spike.
As I stated, the podcast and the experienced person being interviewed were not talking about fat oxidation, but the affects of an insulin spike and subsequent blood sugar dip on your energy levels and sensations (e.g. feeling tired, lethargic, jittery, etc).
I’m not 100% convinced either way but quite frankly, I’ll need someone with more credibility than you to persuade me that the former Head of Sports Science at a World Tour team is entirely peddling “bro science”.
I took your “early” comment to mean during exercise, not beforehand. Rebound hypoglycemia as a result of pre-exercise carbohydrate ingestion is well-established, although just how consequential it normally is seems to be a matter of dispute.
As for Healy, can you provide any more information re. his background? I couldn’t find out much about him from searching the web.
ETA: A bit more digging turned up this. I thought that he was British, but instead he seems to be a Kiwi?
" Daniel Healey joins Tinkoff-Saxo from BMC Racing, where he headed up the team’s sport science division.
Tonkiff-Saxo said that he brings to the team “a wealth of experience having built a cycling specific, multidisciplinary skill set that covers exercise physiology, sports nutrition and hands-on coaching of professional road and track cyclists.”
[. . .]
He was previously head of a supplement programme at the New Zealand Academy of Sport"
After being let go by Tinkoff-Saxo, he seems to have had some involvement with the Zwift rival VirtuGO, but then the trails goes cold. I’ve also been unable to turn up anything about him from before his time with the New Zealand Academy of Sport.
FWIW, I felt like the deep dive on the carbs and gels piece was super interesting, but there was a lack of practical take-away advice here, other than usual “everyone is different, experiment”. Even Amber sorta brought up her question of fueling every workout/ride she’s doing with carbs, but it wasn’t fully addressed. I don’t feel like I got any actionable advice. Sorry to complain.
Even just some broad strokes, general recs/guidelines, or a if-that-then-this type of practical way to figure out if your diet off and on the bike is okay.