Two teaspoons of vinegar taken with a high-carbohydrate meal lowers blood sugar and insulin by as much as 34 percent, and taking it just before the meal was more effective than taking it five hours before meals.28 The addition of vinegar for sushi rice lowered the glycemic index of white rice by almost 40 percent.29 Addition of pickled vegetables and fermented soybeans (nattō) also significantly lowered the glycemic index of the rice.
