What effect does exercise have on insulin? How to time around meals for fat burn + muscle gain?

Commented on September 29, 2014
Created September 28, 2014 at 1:07 AM

Lately, I've been doing 2 meals a day, both high in fat.  I like to hit the gym or do some form of exercise in the mornings most days fasted, where I usually come home and eat afterwards in that recovery window.

I came across a post where some ketogenic diets avoid fat in the meals post-exercise because of a rise in insulin which promotes storage.  So, now I'm wondering if I should wait 2-3 hours after exercising to eat?  (Or, maybe I should eat before exercising and wait a few hours for that to digest?  Or, maybe I could add a 3rd meal in with just a bit of protein and carbs post-exercise?)

I'm reminded of this podcast around the 48m mark http://robbwolf.com/2010/08/31/the-paleolithic-solution-episode-43/ where he mentions upwards of 80% of ones calories would be consumed in the post workout window.  (But, does that apply to a HFLC diet?)

Where is a good place to time a workout / meals to make the best use of insulin while avoiding the negatives?

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on September 28, 2014
at 02:28 PM

Working out fasted is indeed your best bet.  You could also look at doing some CT as well.  Ideal would be to work out fasted while wearing an ice vest as this forces you to burn a lot of fuel quicker.


You could also skip the post workout meal for an hour or so and keep burning more calories. (Most of this stuff comes from Art De Vany, though the CT stuff would be from Ray Cronise, the carb refeed stuff from John Keifer.)


Another good trick to reset insulin resistance is to go from very low carbs, to a very high fast digesting carb meal post workout (or same night after your workout).  You'd want very insulogenic carbs.  You could do stuff like maple syrup slathered yams or even white rice.  (Ideally avoid white sugar due to the fructose).  The idea here is to present your cells with both a very low insulin situation and a very high insulin spike, so they get sensitized to both states.


There is one point where fructose is fine, and that's when you know you've depleted your liver glycogen stores, this is typically after a high intensity workout that has both weight training and cardio aspects. 

In this state, the liver will immediately convert fructose into glycogen rather than into triglycerides.

There was some paper somewhere that said the best way to burn calories is to alternate between cardio and resistance within the same workout - that is you'd do a bunch of sets of weights, then switch to doing cardio - say on a treadmill or bike, then go back to the weights and repeat.  It sounds very brutal.  I believe I saw that on the suppversity blog.  But the gains are kinda minimal over normal workouts, so YMMV.


So what happens after a workout is that you've burned through your glycogen stores, both muscle and liver, and your body now signals cortisol to trigger gluconeogenesis to keep your brain alive.  This uses broken down amino acids which come from the muscles you've damaged. 


But this also has an effect on insulin depending on how much cortisol is released, and your muscles become insulin resistant as well.  This physiological insulin resistance (which also happens by itself if you're just fasting and are doing low carbs) prevents the muscles from consuming glucose and makes them run on fats.  The glycogen is then spared for the brain and red blood cells.  If you consume a post workout meal, it reverses this insulin resistance and allows your muscles to refill with glycogen.


It seems that you do need to have the occasional carb refeed every once in a while if you do HFLC or you'll run into trouble with cortisol in the long run.  Since we try to keep our insulin low and our carbs low to prevent too much ROS, it seems that a brief intense burst of carbs works best as a refeed and prevents these issues, as well as helps keeps us in ketosis most of the time, and prevents too much cortisol from messing up our sleep and causing other issues such as fat gain.




on September 29, 2014
at 10:33 AM

Whey is insulogenic, so it may offset the ketones you'd get from MCT.  Try moving it to after the workout and the MCTs right before.



on September 28, 2014
at 07:06 PM

Great info, thanks!  I'm going to slide that post-workout meal out of the way a bit more.

I'm definitely into the prospects of CT and working with some cold exposure this winter.  I tend to get a little cold when my calories aren't adequate, so I'm hoping to lean out a little bit into the cold months then fire up the heater around december with a caloric surplus and some extra protein and refeeds for gains.  (How many g of carbs and how often?)

I'd gotten in the habit of doing long aeorobic workouts for the challenge / skill of building up some distance and endurance.  I tried switching back and forth today and it was a nice change up -- easier on the joints, though it doesn't feel as good on the ego as hitting 6 or 8 miles head on.  If that can burn more fat, count me in.

I tried a pre-workout drink of a little more than 2 TBS MCT oil with 15g or so of whey for the BCAAs in some goats milk.  It didn't seem to offer much during the workout (I'm wondering if the insulin secretion there is counter-productive), although post-2hr-1100kcal-workout, I'm not particularly hungry and blood sugar is fine.  Not sure if I should experiment more with that or ditch it.

Any thoughts on ideal heart rates or zones to work with?  I've been playing with a range from 180-age-10 or so to 180-age+5 with the occasional sprint for fun.  Though, when I lift it almost looks like HIIT from 115 to 145 or so. imgur[dot]com/mTarK2A.png (this thing won't let me post a link without 30+ "reputation points")

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