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By Bonnie Jenkins, Advanced Natural Medicine
Every January, just like clockwork, our thoughts seem to turn to weight loss. And, every January, many of us look for a shortcut – something that will make quick and easy work of those excess pounds.
Over the past few years, the glycemic index (GI) looked like it was the magic bullet we had been looking for. This system ranks foods according to how much they raise blood sugar (glucose) and was first developed as a tool to help people with diabetes control their blood sugar. Now, it’s squarely in the public mainstream: low-GI diet books crowd bookstore shelves, many diet plans have “low-glycemic” variations, and Australian supermarkets even have foods labeled with their GI ratings.
But a huge debate about the value of the GI is raging in the nutrition community. What makes the index so controversial? And is there anything beneficial about low-GI eating that we can apply to our own lives?
The Big Debate
Here’s how it works: The glycemic index measures how much a fixed quantity of different foods raises your blood-sugar levels compared with pure glucose (the GI equivalent of 100). Foods with a high GI value (greater than 70) tend to cause a higher spike in blood sugar – and in insulin, the hormone that helps glucose get into cells. These spikes are especially problematic for people with diabetes, because they lack an effective insulin system to clear the sugar from their blood.
But here’s where the controversy comes in. Some nutritionists believe that because high-GI foods are so quickly metabolized, they tend to make you hungry again soon after eating. The also think that, because lower-GI foods (under 55) are metabolized more slowly, they keep your appetite on a more even keel. In fact, some even suggest that by tempering blood-sugar surges, eating low-GI foods may help prevent the damage to cells that’s caused by high blood-glucose concentrations.
But not everyone agrees. Those in the anti-GI camp point out a major weakness in using the system: The glucose response to foods can vary widely from person to person – and even in the same person from day to day – so the numbers don’t tell the whole story. A low GI score is no guarantee of healthy fare, either: cola (63), potato chips (54), and even some candies (a Snickers bar is 55) qualify as low or moderate GI.
Beyond Weight Control
Despite these limitations, some studies do suggest the GI concept holds promise. Following low-GI eating principles can help people with diabetes fine-tune their blood-sugar responses and may even help people with pre-diabetes lower their risk of progressing to full-blown disease. New research also connects low-GI diets with lower risk of age-related macular degeneration, a major cause of blindness, and other work suggests a possible link with reducing risk for heart disease and even colorectal cancer.
And of course, there’s the tantalizing possibility that by its moderating effects on blood sugar and, thus, appetite, eating a low-GI diet may help people lose weight. Unfortunately, research results in this area have been mixed.
Low-GI diets seem to be most effective in people whose bodies secrete more insulin: more often “apple-shaped” people, who accumulate extra fat around their waists, compared to people with lower-body fat (“pear shapes”). But, regardless of body shape, those who follow low-glycemic diets do improve their triglyceride and HDL cholesterol levels.
Will the great GI debate end anytime soon? Probably not. But I think the concept makes some sense. For the most part, low-GI foods are more natural, whole, unpolished, and unprocessed. Getting more of these types of foods is smart eating, no matter which side you’re on.
One Last Thing …
Following the GI system can be confusing – especially if you spend too much time crunching numbers. Knowing a few overall principles can make low-glycemic eating a lot simpler …
Bigger is better. Large food particles take longer for the body to break down and absorb, so they move more slowly through your digestive system. So the more intact and less processed a food is, the lower its GI. Think whole rather than refined grains, whole fruit rather than fruit juice, steel-cut oats rather than instant oatmeal, and stone-ground rather than plain cornmeal. When buying whole-grain bread, choose stone-ground, sprouted, or cracked-wheat types; the grain kernels should be visible.
Fiber up. By definition, fiber is the part of plant foods that can’t be digested, so fiber-rich foods like beans, nuts, dried fruits, high-fiber cereals, whole wheat pasta, and whole grain breads are inherently low on the GI scale. Focus on boosting fiber by eating more foods like these, and you won’t have to think about GI.
Pair with protein. When it has protein to break down, the stomach empties more slowly. Adding a little protein to a carbohydrate-based meal or snack – a few chicken strips to your salad or a light smear of peanut butter on your toast – can lower the GI value of your meal.
Drizzle on a healthy fat. Like protein, fat molecules also slow down digestion, so including a little fat can lower a food’s GI and make it more satisfying. Be sure to choose heart-healthy unsaturated fats like olive oil and nuts. And, if you’re watching calories, make sure you don’t go overboard.
Research Brief …
If you suffer from a long-standing health problem, and you happen to wear dentures, check out the label on your denture adhesive. Researchers have discovered that some popular denture adhesives contain high levels of zinc – and it could be causing many chronic health problems, especially if the adhesives have been used in liberal quantities and for a long time.
Two brands, Fixodent and PoliGrip, contain zinc concentrations ranging from 17,000 to 34,000 ug/g. Using two tubes a week would expose you to about 330 mg. of zinc per day. Excessive zinc intake causes copper deficiency, which, in turn, can lead to irregular heart rhythm (arrhythmia), anemia, impaired immune function, and nervous system problems.
References:
de Rougemont A, Normand S, Nazare JA, et al. “Beneficial effects of a 5-week low-glycaemic index regimen on weight control and cardiovascular risk factors in overweight non-diabetic subjects.”British Journal of Nutrition. 2007;98:1288-1298.
Kaushik S, Wang JJ, Flood V, et al. “Dietary glycemic index and the risk of age-related macular degeneration.” American Journal of Clinical Nutrition. 2008;88:1104-1110.
Nations SP, Boyer PJ, Love LA, et al. “Denture cream: An unusual source of excess zinc, leading to hypocupremia and neurologic disease.” Neurology. 2008; 71: 639-643.
van Schothorst EM, Bunschoten A, Schrauwen P, et al. “Effects of a high-fat, low- versus high-glycemic index diet: retardation of insulin resistance involves adipose tissue modulation.”FASEB Journal. 2008 Nov 26. [Epub ahead of print].
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