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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.

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awesome question. – speno Apr 3 2010 at 11:48
Why you are singling out SFA- shouldn't any high fat diet should lead to insulin resistance? – HealthRediscovery Apr 3 2010 at 15:10
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 I was under the impression that palmitic acid uniquely acted as a signal to induce global insulin resistance and switch the body to fat-burning, because as the most common SFA it would be what we'd be releasing into our bloodstreams during starvation. If we're talking about specific tissue insulin resistance, then maybe being full of any sort of fact has the same effect. – David Moss Apr 4 2010 at 8:43
And that is why fructose is so bad. A la Matt Lalonde - it turns to palmitic acid, which signals insulin resistance as if eating a high fat diet, but there is still elevated blood sugar then blamo - diabetes. THis is with excessive consumption I might add. – none May 31 2011 at 15:38
@ meridith. Isn't one of the other reasons why fructose is bad specifically is that the fat accumulates preferentially in the liver, thus causing hepatic insulin resistance (which seems to be a lot more problematic than peripheral insulin resistance)? – David Moss May 31 2011 at 17:16
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4 Answers

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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.

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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?

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 ...except insulin sensitivity would be higher post-workout compared to pre-workout, therefore making that a better time to have your carbs. – Mikael Jansson Apr 3 2010 at 17:14
Yes, that is a good point. I just haven't seen any convincing evidence or arguments that it is important because of that (or other factors) to consume carbs post-workout instead of pre. – HealthRediscovery Apr 4 2010 at 13:57
@HR Agree that it's only important to have topped up by next workout, not to top up post-WO per se. As MJ says though, doing it post-WO would be preferable (assuming you eat the same amount of carb between WO's) since the muscles would be more insulin sensitive. My Q wasn't about whether we should eat carb post-WO though, but about whether (when we eat carb to top up muscle glycogen) we should have SFA with it, ideally. Agree that not topping up glycogen has its advantages too (for fat loss), but I've definitely found I need some glycogen to perform intense exercise... – David Moss Apr 4 2010 at 18:51
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 ...Not sure potatos pre-workout would be the best way. Surely this would be putting glucose in the bloodstream and fuelling your workout from this, mostly? That's fine, but different to topping up glycogen while LCing (running metabolism on fat, but with glycogen in the muscles for intense activity). Also I'd not have thought that carbs+insulin pre-workout was best. This is why I like fasted workouts: less insulin = more energy in bloodstream and more HGH. If carbs are being stored as glycogen pre-WO, then you're getting a hit of insulin to remove energy from the bloodstream as you exercise... – David Moss Apr 4 2010 at 19:02
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 David, I definitely agree eating before a workout is not optimal- I usually workout in the morning without breakfast or at least 4 hours fasted at night. Your comments are exactly what I have been thinking about- couldn't have said it better myself. It seems like we need to stop thinking and do some real research. I am doubtful that there will be much good research literature- will have to be self-experimentation. I am planning on getting a blood glucose meter to help out. – HealthRediscovery Apr 5 2010 at 4:42
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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...!

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Interesting. Well if VLC lowers insulin then it should raise HGH. This link (entropyproduction.blogspot.com/2009/03/…) also suggests that HGH induces insulin resistance (when blood glucose is low), so it's interesting that steroids produce the same effect. – David Moss Apr 6 2010 at 14:03
Thanks for the link David. Certainly reinforces my doubts over the idea that carbohydrates are somehow mandatory for muscle-building, which is still quite pervasive it seems. – Chris Ford Apr 8 2010 at 14:24
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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.)

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I'd have thought carbs shortly before WO would be the worst scenario, as discussed above with HR, you'd be running your metabolism on glucose and heightened insulin. Having them 5+ hrs before might well top up glycogen but surely not as effectively as doing so closer to your last workout. Certainly agree that the bodybuilding dogma that carbs/fast-digesting carbs are essential is woefully inaccurate. I just have enough carbs to restore some glycogen post-WO and next to none anywhen else. – David Moss Apr 8 2010 at 9:26

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