A few weeks ago I was flying to some godforsaken hell hole (I wasn’t, I’m totally making this up) and found myself having this conversation with a chap who believed that insulin inhibits fat loss:
The key message to sink in from this highly emotional and sophisticated dialogue is that insulin does hinder fat oxidation aka fat burning but this DOES NOT STOP FAT LOSS FROM OCCURRING.
Say you wake up but you skip breakfast. Your body is now using stored fat for fuel. Later, you eat lunch—insulin surges, and your body stops burning stored energy and starts using calories you just consumed.
But that does not prevent fat loss from occurring because your body will quickly return to a natural state—glucose will be removed from the bloodstream and your metabolism will be humming along on a mix of fuels that includes more fat than glucose.
Consistently eat fewer calories than you burn and your body will spend more time burning stored fat than the energy you provide:
That’s exactly what we see in the literature too—when calorie deficit is applied, insulin response in healthy individuals has no impact on fat loss. To put it more delicately—it doesn’t mean jack shit.
de Luis et al. found that insulin response had no influence on fat loss with a calorie-restricted diet:
Noakes et al. found no difference in fat loss among 3 diets ranging from 4%-70% in carbohydrate intake despite a 33% greater decline in insulin levels caused by the lowest-carb diet:

And then we have fuck loads of other studies1,2,3,4,5 that would make brainless troglodyte Jessica go nuts—insulin-lowering/low-glycemic diets don’t result in better fat loss compared to high-insulin/high-glycemic diets:

Insulin does NOT prevent fat loss, m’kay? Fat loss will always be governed by total calories in vs calories out regardless of what insulin is doing. If anyone tells you otherwise, high-five them in the face with a chair.
So eat your carbohydrates, eat your fruits, eat your goddamn grains, stay in a caloric deficit, and don’t worry about insulin. It’s just doing its job. It’s your fault if you act like a mindless muppet and ‘give’ insulin too much food to play around.
And if you aren’t sure exactly what to do to get fit or how to do it, hire me to coach you and save yourself a buttload of time.
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Man, this was hilarious! Thanks for the laughs and the info. I’m going to share this with Jessica now!
Haha No worries!
Hey,thanks for the great information. I learned that fat loss is all about IN VS OUT actually. I eat mostly healthy and crap foods everyday too but I’m in deficit(1400-1600cal).
I was having worries about insulin staff but then I got that&learned that thanks to you. I’m 166 and have %17 body fat,goal is to reduce that range to %14-15 by being in deficit&lifting&HIIT.
Thanks bud.
No worries, mate.