Friday, October 8, 2010

All about sugar

I read an article in Reader's Digest many years ago titled Killer Sugar.  It's probably outdated in many respects but not in its conclusion, as expressed in the article's title.  But sugar takes many forms and not all are equally bad, and its effects on our health can be moderated by other foods we eat.  Raw honey, for example, has a glycemic index (GI) of about 30, which is considered low and relatively safe, whereas baked potatoes, watermelon, corn flakes, and white bread are in the high GI range of 70 and above.  From Wikipedia:
The glycemic index, glycaemic index, or GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI; carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream, have a low GI.

A low-GI food will release glucose more slowly and steadily. A high-GI food causes a more rapid rise in blood glucose levels and is suitable for energy recovery after endurance exercise or for a person experiencing hypoglycemia.

The glycemic effect of foods depends on a number of factors such as the type of starch (amylose versus amylopectin), physical entrapment of the starch molecules within the food, fat and protein content of the food and organic acids or their salts in the meal — adding vinegar, for example, will lower the GI. The presence of fat or soluble dietary fiber can slow the gastric emptying rate, thus lowering the GI. In general, unrefined breads with higher amounts of fiber have a lower GI value than white breads. Many brown breads, however, are treated with enzymes to soften the crust, which makes the starch more accessible (high GI).

While adding butter or oil will lower the GI of a meal, the GI ranking does not change. That is, with or without additions, there is still a higher blood glucose curve after white bread than after a low-GI bread such as pumpernickel.
Mark Sisson of Mark's Daily Apple has published what he calls The Definitive Guide to Sugar.  Here is his list of warnings about sugar:
  • Sugar stimulates a physiological stressor-reaction cascade that provokes adrenaline and cortisol release and thickens the blood.
  • Sugar effectively disables your immune system by impairing white blood cells’ functioning.
  • Sugar decreases your body’s production of leptin, a hormone critical for appetite regulation.
  • Sugar induces significant oxidative stress in the body.
  • Sugar appears to fuel cancer cells. **[See below] (Check out Free the Animal for much more on the cancer connection.) [In particular, see this article.]
  • Sugar promotes fat storage and weight gain.
  • Sugar disrupts the effective transfer of amino acids to muscle tissue.
  • Sugar intake over time spurs insulin resistance, subsequent Type II diabetes and the entire host of related health issues like nerve damage and cardiovascular disease.
And sugar is also addictive. Sisson writes:
A common theory says that we evolved to crave sweet tastes in order to seek out healthy fruits to diversify our diets. The problem comes in the current age when our inclination is bombarded with the likes of Coco Puffs, Snickers and pudding packs. . . .
Sugar raises serotonin levels, and that boost can easily figure into [your sugar] cravings. But guess what? Exercise raises serotonin as well. If you can, plan your workouts around the time of day when cravings tend to hit.
Read his post.

** "The quest is not to eliminate sugars or carbohydrates from the diet but rather to control blood glucose within a narrow range to help starve the cancer and bolster immune function.  The glycemic index is a measure of how a given food affects blood-glucose levels, with each food assigned a numbered rating. The lower the rating, the slower the digestion and absorption process, which provides a healthier, more gradual infusion of sugars into the bloodstream."

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