Dr. Richard Bernstein cautions his diabetic patients and readers of Diabetes Solution to keep a tight lid on consumption of tomatoes. An excerpt from page 149:
If you have them uncooked in salad, limit yourself to one slice or a single cherry tomato per cup of salad.
His concern is that tomatoes will raise your blood sugar too high.
That doesn’t make sense to me. A 3-inch diameter tomato has 7 grams of carbohydrate, 2 of which are fiber. So the digestible carb count is only 5 grams. That’s not much. So do tomatoes have a high glycemic index? Unlikely, although it’s hard to be sure. Good luck finding a reliable GI for tomatoes on the Internet.
I think Dr. Bernstein’s wrong about this one, which is rare. I suppose it’s possible that tomatoes deliver some other substance to the bloodstream that interferes with carbohydrate metabolism, but Dr. Bernstein doesn’t mention that.
Do tomatoes play havoc with your blood sugars?