A P P E N D I X A
What About the Widely Advocated Dietary Restrictions on Fat, Protein, and Salt, and the Current High-Fiber Fad?
So what’s wrong with that?
As attractive as it may seem, the concept is clearly flawed in three respects: First, diabetics show much higher blood sugar increases than nondiabetics. Second, digestion of the carbohydrate portion of a meal typically takes at least 5 hours (in the absence of gastroparesis), and the index ignores effects upon blood sugar that last longer than 3 hours. Finally, the index is an average, and true numbers have been found to vary considerably from one person to another, from one time to another, and from one study to another. As I’ve pointed out, a food that makes my blood sugar rise dramatically may have little or no effect on that of one of my patients who still makes some insulin.
Unfortunately, many dieticians and diabetes educators still recommend foods that have been “shown” to have a “low” glycemic index in some study, and assume that an index of 40 or 50 percent is low. They may thus select apples, lima beans, and the like as appropriate for diabetics, even though consumption of typical portions of these foods will cause considerable blood sugar elevations in diabetics.
A “medium-sized” apple, according to one table of food values, contains 21 grams of carbohydrate. It will raise my own blood sugar by 105 mg/dl, and much more rapidly than I can prevent with an injection of rapid-acting insulin. Peanuts usually have the lowest glycemic index in many studies (about 15 percent), yet 1 ounce contains 6 grams of carbohydrate and close to 1 ounce of protein. I’ve found this portion to raise my blood sugar by 80 mg/dl, albeit much more slowly than the apple. Since peanuts work so slowly (more slowly than 3 hours), I can substitute 1 ounce for 6 grams carbohydrate and 1 ounce protein in a meal—but who can eat only one handful of peanuts?* The carbohydrate foods that we recommend, salads and selected vegetables (Chapter 9), have glycemic indices lower than peanuts and work more slowly. Furthermore, they are more filling. The issue here, though, is to understand that such indices are unreliable and won’t help you keep your blood sugars normalized.
WHAT DIET WILL WORK FOR YOU?
Actual results are the yardstick for an appropriate diet. We have the tools for self-monitoring of blood sugar and blood pressure. We have tests for measuring kidney function, HgbA1C, thrombotic risk profiles, and lipid profiles (see Chapter 2). Under your doctor’s supervision, try our diet recommendations for at least three months. Then try any other diet plan for three months and see what happens. The differences may not be in the direction that the popular literature would predict.
Finally, in its most common usage, “diet” usually indicates some sort of franchise. “The______Diet” (you can fill in the blank) usually has a particular name or marketing term associated with it and often comes with products ready for your consumption. When I use the term, I’m referring to diet in the very simple sense of what you eat. I’m not selling a brand or products, but providing guidelines so that you can understand how foods are likely to affect you. You can then create your own diet, one that will not only allow you to keep your blood sugars normalized but also to satisfy yourself.
*By the way, natural peanut butter has a glycemic index much higher than that of the peanuts from which it was created because it is digested more rapidly.