I am risking myself here today by witting about pre and post exercise carbohydrate loading. I will immediately admit I had no idea some athletes were “POST EXERCISE RELOADING” on carbohydrates to replenish their glycogen reserve. As you see, it is not a field I master and reality is, over that, I am far away from being an athlete…
I will voluntary avoid the debate of what macronutrient is better for athletes performance, simply saying there are many good studies documenting a low carb high fat diet provides excellent if not better results. I always believe relying on our body fat reserves to get energy during exercise provide a larger “energy pool” then the limited glycogen reserve. Glycogen was meant to answer immediate energy needs, based on anaerobic metabolism and for short burst of exercise.
What I want to bring up here comes from 2 studies I recently encountered detailing the effect of POST EXERCISE CARB RELOADING on replenishing glycogen reserves. As if PRE exercise carbohydrate loading was not enough stress on the metabolism…
I was under shock when the studies describe an INCREASE of blood sugar during this carbohydrate-reloading phase (these were endurance trained men), getting numbers between 120 and 160 mg/dl. THIS MEANS SOME OF THESE HEALTHY ATHLETES are showing sings of INSULIN RESISTANCE (anything over 140 mg/dl. is significant), the worst being the searchers didn’t really care about commenting this observation…
But as if this was not enough, their INSULIN levels had a 5-fold increase over resting values, which, as we know, is the road for more insulin resistance and eventually full-blown diabetes with all the related health consequences.
The studies show a difference between a "pure glucose post exercise reloading" and a "starch-based reloading" on body parameters, low-glycemic index looking better then high-glycemic index (which we would expect). But, still, blood sugar did go up and there was a 4-fold increase in insulin levels.
Continuing on the effect of this "reloading", they also observed blood sugar went DOWN in some athletes, as low as 63 mg/dl, which brought them in the HYPOGLYCEMIC zone.
Interestingly, they are honest enough to admit the insulin increase did inhibits free fatty acids mobilization (using of body fat as source of energy) and this, on return, did affected negatively performance.
To resume the story, post exercise carbohydrate reloading may causes hyperglycemia, as well as hypoglycemia, and a serious increase in blood level of insulin, which are all serious metabolism changes that will slowly kill pancreatic cells and cause diabetes, WHILE affecting athlete’s endurance.
Anyway, we know folks on a ketogenic diet are quite efficient into “recycling glycogen”. When your muscles use glycogen to get the glucose they need, they also produce lactate molecules as a by-product , which are sent to the liver and are used, along with ATP from fat sources, for neoglycogenesis (Cori cycle) thus the creation of new glycogen reserve.
As a doctor recently declared on a BBC interview (“The men who got us thin” - episode 2 – on YouTube), it is a big mistake to think because one does a lot of exercise and burns a lot of calories, he has the right to eat whatever he wants thinking he will stay healthy.
Sadly, this is what the producers of COKE want us to believe… certainly not in our interests!!!