Posted by blueboy on July 15, 2008, at 11:15:21
In reply to Anyone else hear over-sensitive to sugar?, posted by chiron on July 14, 2008, at 23:22:06
Science is in the middle of solid discovery in this regard. I'm not sure that they know as much as they think they do, but they know quite a bit at this point due to good funding for diabetes research.
First off, it's not just sugar, it's any unbuffered carbohydrate that will run your blood sugar up in a hurry.
The degree to which food will spike your blood sugar -- run it up really high in a hurry, followed by a crash -- is a function of five factors:
1) The sheer amount of carbohydrates you eat (two doughnuts is worse than one);
2) The net "glycemic index" of the meal. Glycemic index refers to how fast the food is turned into glucose. Sugar and highly refined starches such as white bread are the 600-pound gorillas here. Most glycemic indices set cane sugar = 100. A doughnut will be around 100, a slice of bacon around 5 (or even lower).
3) The total composition of the meal. This is an area where more research is needed, but as far as I can tell, soluble fiber and possibly fat and/or protein can slow carbohydrate absorption. So eating two slices of white toast is very different from eating scrambled eggs and bacon with two slices of white toast; eating an apple is much better than drinking apple juice due to the soluble fiber in the apple.
4) Your ability to handle high blood sugar. This has both genetic and lifestyle factors. Once you beat up your system enough you develop "insulin resistance" and get fat, then eventually type II diabetes.
5) How much exercise you get immediately after or during the period when you eat the carbs. If you are running a long way or playing tennis, drinking a coca-cola is probably 100% okay, since your body grabs the blood sugar and uses it to power your muscles. Drink the same soft drink on an empty stomach for breakfast and you're going to spike and crash.
This is a lot of why Americans are fatter than, say, Italians. If you eat breakfast and walk to work or walk to the market, the walking (which involves, initially, releasing glycogen from your liver in order to turn ADP into ATP in your muscles) will grab some of the blood sugar.
If you eat the same breakfast, then drive your car to the office, the blood sugar has nowhere to go; your body beats it down with insulin but your liver says "keep moving, I'm saturated with glycogen" and so your body goes nuts trying to store it as fat. Meantime your heart is racing, your brain is racing. Then the insulin surge overpowers your blood sugar and drops it below minimum, and your brain gets sluggish from lack of fuel.
You may be able to have the refined carbs *after* exercise safely, I don't know. It might just convert to ATP since you are going to need to replenish it. On the other hand, if you don't have it, your body is perhaps more likely to burn some fat. I'm getting over my head here, though, and just speculating. You can pretty much find an "expert" to support almost anything you want to say. Nutrition is unbelievably complex.
Top level body builders/Weight lifters, who know more about protein nutrition than most dieticians, swear by taking pure protein immediately after weight work as a means of building muscle mass.
Anyway, there are some things science is pretty solid about. If you are sedentary, or have a long sedentary period during the day (i.e. an office job), don't eat a lot of unrefined carbs. Balance meals (including snacks) with some fat and protein, but beware, fat has a lot of calories. The carbs you DO eat, should be in the form of fruit (pure sugar but buffered by soluble fiber) and unrefined carbs (pure starch but again buffered). The "buffering" of fiber will slow digestion and even out the release of glucose. The buffering of fat and perhaps protein will do the same thing, for a somewhat different reason.
It's like burning wood in your fireplace. Sugar/starch is like fat pine -- it burns fast and hot, but burns out quickly. Protein and fat are like oak -- it burns slow and long. Fiber is like cutting down the airflow -- it makes the wood burn slower.
poster:blueboy
thread:839779
URL: http://www.dr-bob.org/babble/20080706/msgs/839838.html