So we know that saturated fat (esp palmitic acid) induces physiological insulin resistance. We also know that this isn't a bad thing when you're eating reasonably low carb- it's a positive adaptation, turning away limited carbohydrate from muscles and allowing it to be used efficiently by the brain. What I'm wondering therefore, is whether this has any significance for eating saturated fat with a post-workout meal, where I'm eating a small amount of carbohydrate to aid recovery. In theory, wouldn't inducing insulin resistance in my muscles be preciely what I don't want to do, if I want a limited amount of insulin to refill my muscle glycogen.
Intuitively, I'm sure this isn't a massive problem. Clearly HG's suffered no serious harm eating their SFA-heavy kill (nor from eating carb post-exertion either), but since we have the luxury of being able to stick to just MUFA or coconut post-workout, what would be optimal?
One thing that seems worth noting is that our muscles would be more insulin sensitive anyway post-workout, so this would somewhat offset matters. Also, perhaps I'm being overly simplistic in assuming that eating SFA induces universal insulin resistance. In his series, Peter talks as though this is the case, but he also talks as though muscles become specifically insulin resistance if they have taken up fatty acids themselves. In this case, would muscle fibres be lacking in fat as well as glycogen post-workout and therefore be insulin sensitive regardless?
The other thing I was wondering, is that Peter says in various places that "muscle runs well on lipids," yet lots of people also say that for recovery post-workout (and optimal growth) muscles really need protein/carb and that intense exercise really needs muscles to have substantial glycogen stores, not just a source of fat.
asked byDavid_Moss (15613)
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on April 03, 2010
at 03:20 PM
Insulin sensitivity will increase by exercise on a high-fat diet, which means that's the one occasion where you want to eat carbs if you do crave them.
Regarding muscular growth, I've heard sarcoplasmic expansion (e.g. by forcing in glycogen into the muscle cell - pure mechanical expansion) causes muscle growth by itself, which means that overeating carbs after working out should have a beneficial effect.
Regarding blood sugar and insulin resistance, read my answer on ideal blood sugar levels at http://paleohacks.com/questions/1717/ideal-blood-sugar-levels/1732#1732 -- as you can see, glucose tolerance after workouts is not a problem.
on April 03, 2010
at 04:03 PM
The first thing you need to answer is: are you looking for optimal athletic performance or are you trying to maximize performance while always focusing on optimal health? I will assume the latter.
I don't know if you have read the blog Theory To Pracice, but I think we have a good example there of someone striving for optimal health and achieving great athletic performance. Keith even briefly highlighted a fasted workout study.
For optimal athletic performance, you want to make sure that your glycogen stores are full before competition. I am not convinced by any of the information you have cited that there is strong cause to believe it is important to replenish glycogen post-workout.
I have been thinking about glycogen recovery a little. For health purposes, post-workout glycogen replenishment seems counter-intuitive. Having lower glycogen levels will give you a place to store future carb intake, providing more insurance against incidentally high carbohydrate meals, and keep you in fat-fueled mode. Then, for better athletic performance you can eat your potatoes before your workouts to increase glycogen stores. This seems like a better approach, unless you are worried that you will be consuming carbohydrate an an insulin resistant state? But that state is a response to no carbohydrates. Wouldn't we expect you to snap out of it when carbohydrates are consumed?
on April 06, 2010
at 11:27 AM
Also worth bearing in mind, I believe I've heard (on Super Human Radio possibly) that anabolic steroids produce muscle insulin resistance also... not saying that VLC will make you jacked, but it's food for thought...!
on April 07, 2010
at 07:05 PM
I suspect the "right" answer about when to consume carbs in relation to working out is highly individualized.
I've been paleo since November and have tried various approaches. I found that if went into my workout very low on carbs, I just didn't have the energy to put in an intense training session. So now I have some rice or tubers a few hours before. On the other hand, Mauro di Pasquale and Robb Wolfe persuaded me that carbs post-workout are not necessary. So I just have a protein shake, and I haven't noticed my strength suffering. (This horrifies my training partner, who is a very successful natural bodybuilder and thinks fast-digesting post-workout carbs are essential.)