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View Full Version : Higher blood sugar desirable near workout window or not?


Jeff Evans
04-28-2008, 06:25 PM
I originally asked this on the Crossfit nutrition forum but didn't get any responses there.

I can't reconcile this. In Nutrient Timing, Dr. Ivy basically argues that it's ideal to raise your blood sugar level just at the end of a workout, because your muscles are more receptive to glycogen intake during that window, which closes quickly (like within half an hour of the end of the workout). Also you need insulin to build muscle, so increasing your insulin window during this time means your muscles will regenerate more effectively during the recovery and eating period to follow. This all seems to make sense.

On the other hand, in Protein Power, Eades/Eades argue that the critical component in muscular development is HGH (human growth hormone, generally recognized as very good stuff), and that the release of HGH is attenuated in the face of high blood sugar. Therefore you shouldn't eat any carbohydrate before, during, or after your workout. You should just have a high protein/fat meal an hour after lifting because HGH will be manufactured if you keep your blood sugar low.

OK so what am I missing? If one of them is wrong then which one? If they're both right then which negative (or positive) factor is dominating? :confused:

Robb Wolf
05-07-2008, 04:48 PM
Jeff-
This topic gets hashed about a good bit and for good reason: it depends. There is no doubt that carbs post WO, particularly a hard metabolic session ala-crossfit, will improve recovery...both in terms of glycogen repletion AND muscle recovery/growth. That said we also see some very interesting adaptations with a low/no carb post WO period with regards to fat adaptation and some cellular stress adaptations that might be quite favorable for health and longevity.

There is likely some break-even point of being able to sneak in some carbs post WO without perturbing the whole insulin situation such that we get serious downsides. The solution I've found in this regard is to eat most of my carbs post WO and i keep this to REAL food. A portable non-retch inducing meal I've been using lately is a small pop-top can of salmon from trader joes (wild salmon) and ~100g of carbs from a yam. The remainder of my meals are protein and fat...some greens. Performance is good, I feel good...sleep is good etc. No symptoms of elevated insulin levels as evidenced by leanness and clear thinking.

You can find more info on this topic in threads like the health and longevity bias...i think I had something on my blog a while back also.

Steven Low
05-07-2008, 05:39 PM
Depends on the person like Robb said. Basically figure out which one will work better for you with some experimentation.

hGH and insulin although exerting the near the same effects for muscle growth tend to negate each other. The one main difference is insulin promotes uptake of nutrients by adipocytes while hGH stimulates lipolysis. Well, actually hGH has better overall effects via IGF-1 (insulin like growth factor 1) so tending towards not-so-big insulin spiking if you are going to do that is a good idea (aka real food like Robb is talking about).

I've had better results with real food so I'm gonna stick with that.

Mike ODonnell
05-07-2008, 06:14 PM
Fasted state before workout will give great GH response
You don't need PWO drinks and shakes (if anything amino acids will do)
Eat a meal an hour PWO that is more whole food carbs and protein (low fat)
Eat Meat/Fat/Veggies the rest of the day
Get plenty of sleep
If your goal is fat loss, keep calories lower....if you want mass eat more

Jeff Evans
05-07-2008, 08:19 PM
Thanks for the replies everyone! I tried to make my question academic in nature but in reality I have a personal goal of losing fat while maintaining (or even gaining) strength on o-lifts. Gaining strength should not be difficult since I'm barely above the untrained level on the Crossfit tables. For a while I tried having some whey powder and dried fruit (or Larabar) after lifting with no noticeable result (a bit of extra fat gain if anything). These days I'm trying to get myself fat adapted so I've been cutting way down on carbs in general (particularly dried fruit which was probably my biggest prior GI sin). I may try to incorporate some whole food sources of carbs post lifting (like fruit or yam as suggested) to see if that makes a difference, while avoiding them at other times.

Anyway reading Eades more closely now, he does say you get the biggest HGH "bump" during sleep so I should perhaps focus on getting a bit more. With this in mind it probably also makes sense to keep blood sugar low before bedtime to avoid any HGH impediment during this key time.

I will continue to follow all of your posts (both here and on Crossfit boards) with great interest as I seek to solve my body comp puzzle once and for all. Thanks again.

Steven Low
05-07-2008, 09:41 PM
~60-70% of GH is released during sleep.

If neuroendocrine response is in next months PMenu you'll read some stuff more about GH and how it coincides with working out.. though I didn't talk about PWO nutrition.

Mike ODonnell
05-08-2008, 06:57 AM
Yep...if you want GH response at night...eat 3 hours before bed time. (NO snacking before bed). Also dump the dried fruit and other sugars....there is no place for them if weight loss is your goal. Here's something (http://projectfit.org/iflifeblog/2008/02/25/fat-loss-101-master-the-basics/) I did a while back on hormones (including GH) and fat loss....it may help clear some things up.