Will eating some fat before Z2 rides help fat oxidation during?

I like your approach!! Thanks for the references too I am definitely going to check these out.

Other than dropping some weight, I want to work to be an effective fat burner because there are a few big rides I want to do next year (150-180 miles) so I know those will be a lower IF and I don’t want to be slamming gels the whole way. There’s so much good info in this thread to thanks to everyone for the input!!

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That entire article can be summed up in two sentences:

“At present, the only proven way to increase fat oxidation during exercise is to perform regular physical activity.”

“changes in body weight and body composition can only be achieved with a negative energy balance: you have to eat fewer calories than you expend, independent of the fuels you use!”

Yet ironically, Jeukendrup has rather bizarrely pursued “Fatmax”, which is just another measure of lactate threshold. You think he would know better!

What evidence is that?

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@FrankTuna I used to take down a tbsp of coconut oil before Z2 rides and then just not eat during the ride. Tried to get in a 90 min or 120 min ride.

If I’m being honest: it didn’t really provide any noticeable improvement in fat oxidation…but who knows what a real gas exchange analysis would have shown. But it did have a powerful psychological effect. And it helps you feel satiated during the ride instead of dealing with a growling stomach right the way through.

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This thread would do well to remember what the OP said

I think we all agree that performance in a high intenisty (effort requirement) competitive situation will suffer if you cannot process carbs…ultra distance events less so.

What we are talking about here is fat loss, they already acknowledged that a calorie deficit will be employed and they’re looking at boosting the loss by using fat as a fuel.

Now, whether or not this can be accomplished in the short to medium term is open to debate.

I think the main advantage of taking down 120kcal of pure fat before a z2 ride is that you can do the ride w/o any hunger pangs. In fact, for me, with such an approach you can do the ride in the morning & go fasted without any discomfort pretty much until lunchtime.

So the advantage is primarily psychological. For taking down 120kcal you can stay fasted without much willpower for half the day…plus book the calorie deficit created by the z2 workout.

If you wanna do some intensity, plan accordingly & take down the carbs 4 to 6 hours before the workout…then feed with carbs during the workout.

Anyhow that would be my approach.

This thread would do well to remember what Jeukendrup wrote:

“changes in body weight and body composition can only be achieved with a negative energy balance: you have to eat fewer calories than you expend, independent of the fuels you use!”

IOW, no, it’s not really open to debate.

That’s not what I said though. We are fundamentally agreeing, what i am saying is open for debate is how long it will take. Calorie deficit over the long term should result in fat loss but I’m wondering about, and said, short to medium term.

This makes sense to me. I’ve used coconut oil before and I actually think it sometimes helps give me a little mental boost (maybe it’s a placebo who knows).

Coconut oil is an MCT so can actually be used very quickly by the body. It’s not processed in quite the same way as other fats.

More generally:

I genuinely doubt the OP can achieve measurable difference in weight/fat loss by focusing on fat oxidation during long rides.

Study after study has shown that fasted exercise does not result in a greater fat loss when calorie intake and exercise time and intensity were equated.

And (not aiming this at anyone in this thread) people need to remember that energy balance (calorie surplus/deficit) takes place over days or weeks, not merely a morning.

Eat in a modest deficit, concentrate more of your calories and carbs around and in the workout, drink plenty of water, and weight loss will come. Throw in a bit of resistance training to maintain muscle mass and job done: simple. N.b.: simple does not = easy.

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Jeukendrup has studied MCTs. They are more readily oxidized, but you’ll have GI issues before you can ingest enough to really make a difference in fuel use during exercise.

Yep. It’s just got an ok-to-neutral flavor that doesn’t repulse me. Plus it’s got a good mouth feel. I would usually rotate it with Udo’s Choice…which is a lot more expensive.

Anyhow, the real point is just to squash the feeling of hunger. Between a tbsp of oil and a couple hours of Z2 I wouldn’t be hungry again until lunch. More than anything, that’s what’s gonna help you burn off fat. Longer periods of low insulin & calorie deficit. I think you’re on the correct path!



The most likely reason you are feeling your hunger “squashed” by utilizing MCT in the morning is because you are not triggering the hormone release accompanied by the ingestion of carbohydrates. No carbohydrate ingestion means no release of their associated hormones.

Have you ever felt a full stomach after ingesting carbohydrates but still had cravings for food? It is the hormones associated with ingesting the CHO which are causing the cravings.

Recently read a meta-study about the satiation properties of CHO, fat, and protein. Basically protein is more satiating but only up to a naturally occurring point, then it’s all the same.

Also talked about hormones/chems and how some instances of fat and protein can cause greater surges than some CHO products.

Interesting, sure, but there’s bigger and easier gains to chase than trying to faff about with marginal ratios and timing. We don’t live in a lab, after all.

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Short answer: No.

c’mon then @sryke -lets see the evidence for this then. If it were the case we’d all be having a bucket of lard before heading out for long rides to burn more fat. The study you linked to suggested that trained people burn better but suggests anyone who trains would - and still at different intensities.

As @old_but_not_dead_yet has said and others have agreed with it’s about caloric deficit over a period of time which the study supports/states.

I don’t pay attention to postings by old man. I’m not interested in his “contributions” to this forum.

The linked text by Jeukendrup is not a study. And you make it sound as if I contradicted Jeukendrup.

A review article by Hawley et al (1998). Sports Medicine 25(4):241 cites several studies where acute/short term high fat feeding increased fat oxidation in TTE tests. Performance plummeted in these test bur RER was lower. Furthermore, is said that fat infusions (increase of FA in blood plasma) leads to glycogen sparing and increased fat ox. Fat loading for 12h increases intramuscular triglycerides (aka “fat glycogen”) leading to a lower RER in subsequent exercise (Starling et al. 1997). Therefore, it is suggested that an acute increase of plasma FFA and/or intramuscular fat stores leads to lower RER (e.g. higher fat ox).

Therefore “some” evidence. Not necessarily applicable evidence.


Don’t try to move the goalposts. None of the studies you mention involved a single high fat feeding before exercise. To call it “evidence” just serves to confuse people.

Sorry, there seems to be some kind of issue between you two. I was asking as genuinely interested but I’ll leave it there.