Wednesday, March 28, 2012

The daily super stimulus to prevent diabetes, or maybe not?

The daily super stimulus to prevent diabetes, or maybe not?
Today a newly released case report in the British Medical Journal caught my attention: "Towards creating a superstimulus to normalise glucose metabolism in the prediabetic: a case-study in the feast-famine and activity-rest cycle". Normalizing glucose metabolism in the prediabetic person means nothing less than preventing diabetes in those at high risk. Naturally I sought enlightenment. 
According to the report, a healthy subject was fasted for close to 2 days (water consumption was allowed). During that period he performed 3 aerobic sessions of neuromuscular electrical stimulation exercise (NMES). And surprise, surprise, the energy used by the muscle came almost entirely from fat. The subject also went into a hypoglycemic state, which is doctor-speak for low blood sugar. The authors concluded that this may indicate the depletion of carbohydrate stores. And they go on to suspect that this could be the equivalent of "a metabolic super stimulus mimicking the famine-activity periods of our ancestors". A stimulus which they correctly find to be absent from our modern environment. And which might be considered a contributor to the diabetes epidemic, which we are facing in our environment.
Now first what is NMES? It is what it sounds like: the application of an electrical stimulus to muscles. If a muscle gets stimulated in this way it contracts. Once the stimulus is switched off, it relaxes. Do this with a certain frequency and your muscle does almost the same as when you voluntarily move it, by exercising for example. I say "almost" and I will get back to that point in a short while. Now when your muscle contracts it burns energy, typically in the form of carbohydrate or fat. It doesn't matter whether your muscle does its contraction thing because your brain tells him to or whether a NMES device sends its juice through the nerves which otherwise carry the brain's commands to that muscle. if it moves, it burns. That's why NMES is typically applied for muscle rehabilitation, or to prevent muscle wastage when you can't move a limb, or when your personal trainer gets the idea of strengthening it beyond what you already achieved in the gym (not necessarily an effective idea). It's certainly not a substitute for doing exercise. Otherwise we could simply have ourselves full-body-wired to some NMES, flick the switch and start bopping around on the sofa while watching TV, feeding our face, and not getting fat at the same time because the NMES makes our muscles BURN all that fat. 
Come to think about it, why don't you try it and let me know the result? But please don't tell anybody that I asked you to. Specifically not your doctor and also not my ethics board.
But anyway, back to serious thoughts. Why are the results of this case study so underwhelming? First of all, we know, that human carbohydrate stores are so limited, in fact approximately the equivalent of 1600 calories, that your body will go into carb preservation mode much earlier than after 44 hours of fasting. 
We have made in our laboratory tests on people after a simple overnight fast. Their resting resting energy expenditure came almost exclusively from fat. And when we put them on a bicycle to exercise at the intensity which the study authors applied to their NMES guy (50% of VO2max), they also burned fat almost exclusively. The reason is simple: your brain needs glucose, the building block of carbs, to function. So your body starts to burn fat preferentially, once glucose supplies dwindle. When we gave our subjects a banana to eat or some buns or muesli, their bodies switched  to burn carbs almost exclusively within a matter of 15 to 20 minutes. At rest and while exercising.
The message is clear: if you want to burn away your fat reserves, you MUST NOT eat or drink carbs before you exercise. Don't let any gym rat or self-styled guru tell you otherwise. The human body is biased to preserve its fat stores. That was Mother Nature's survival policy for our ancestors for millions of years. Only when glucose levels dwindle will that preference be put on the backburner, so to speak.
So what has this study added to our body of knowledge about the prevention of diabetes? You judge for yourself. But my take is, even if that "super-stimulus" was worth something, who will go through the fun of staying without food for 2 days? And what comes after the 2 days, when you start eating again?
But one message clearly is being reinforced here, a message which I always like to give, specifically to those who are overweight and in need of losing a few pounds of fat: ideally do your aerobic exercise in the morning, every morning, after an overnight fast and before breakfast. And don't you dare take that bottle of energy drink with you on your run. In this way you can create your personal feast famine cycle within the 24 hours of your day, ideally every day. Initially it may be tough. I know because I do it myself. But I also know, after a while you begin to truly enjoy that morning routine. I'm doing this since more than 10 years now. And so does my wife. She has the diabetic gene in her family, but her blood glucose values and her insulin sensitivity are all in the deep green zone. Maybe because of her daily super-stimulus.  
So when will you get yours?
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