Foods that your body quickly converts to sugar—or foods high in sugar without other digestion-slowing nutrients—are no-nos, says Rumsey:
1) Refined carbohydrates. Avoid bagels, pastries, white bread, white pasta, crackers, and cookies. "Refined carbs are ones that have been heavily processed, and the end result has little fiber," says Rumsey. "Once eaten, they are converted to sugar very quickly, which causes a rapid rise in blood sugar."
2) Sugar-sweetened beverages. Instead of soda, sweetened iced tea drinks, juices, and sports drinks, stick to water and other unsweetened beverages. Many sweetened drinks have 8-10 teaspoons of sugar of added sugar in just one bottle, which exceeds the daily recommended limit of 6 teaspoons for women and 9 teaspoons for men, says Rumsey. "There is no fiber to slow digestion, so this sugar is digested fast and causes a big spike in blood sugar."
3) Processed foods with added sugar. The biggest culprits: granola bars, fruit-flavored yogurts, candy, and desserts. Rumsey cautions you to examine nutrition labels carefully. "Food manufacturers can use as many as 6 or 7 different types of sugar in one product," she says.