After you eat, your blood glucose (blood sugar) rises and your pancreas produces insulin to help muscle, fat, and liver cells use that blood glucose for energy. If your body does not make enough insulin or cannot use it well—called insulin resistance—high levels of glucose build up in your blood, setting the stage for diabetes. Having a cluster of any three controllable risk factors—insulin resistance, being overweight (especially around your middle), high blood pressure, HDL (“good” cholesterol) levels below 35 mg/dL, and triglyceride levels above 250 mg/dL—is called metabolic syndrome, and it dramatically increases the likelihood that you’ll develop diabetes.
Type 2 diabetes is perhaps the most aging condition there is. Besides putting you at high risk for heart attack and stroke, having high blood sugar damages nearly every system in the body over time. For example, the high levels of insulin produced in response to excess blood sugar also act on your kidneys (raising your blood pressure), influence the liver enzymes that produce cholesterol, and increase inflammation throughout your body.
Your doctor can use a fasting blood glucose test to check your blood sugar levels in the morning after eight hours of not eating. Normal blood sugar levels are 100 mg/dL or less. Prediabetes, classified as having blood sugar levels of 100 mg/dL to 125 mg/dL, is also dangerous to your heart, but you still have time to turn things around and prevent full-blown diabetes. Diabetes is defined as blood sugar levels of 126 mg/dL or higher.
Most people with prediabetes go on to develop type 2 diabetes within ten years, unless they lose 5 to 7 percent of their body weight (about 10 to 15 pounds [4.5 to 6.8 kg] for someone who weighs 200 pounds [90 kg]) through diet and exercise. Research shows that lifestyle changes are twice as effective at preventing diabetes as medications, and one of the most important changes you can make is to decrease your sugar intake to help keep your blood sugar, insulin levels, and weight in check.
Not all sugar is bad. Some foods, like fruit and milk, contain natural sugars that your cells can use for energy. But they also contain fiber and protein, respectively, to help balance out your blood sugar and prevent an insulin spike. Added sugars are the real problem because they typically break down very quickly and increase your blood sugar too fast—and they’re not always easy to sleuth out. You know to limit obvious offenders like soft drinks, cookies, cakes, ice cream, and doughnuts to once-in-a while treats. Same with sprinkling brown sugar on your oatmeal or pouring syrup on your pancakes. But your morning cereal, canned or frozen fruit, canned baked beans, spaghetti sauce, and other seemingly healthy foods can be sneaky sources of added sugars, even if they don’t taste especially sweet!
The only way to tell if a food has added sugars is to look at the ingredients list. And sugar by any other name tastes just as sweet: Look for names ending in “ose,” such as maltose or sucrose, high fructose corn syrup, molasses, cane sugar, corn sweetener, raw sugar, syrup, honey, or fruit juice concentrates. The American Heart Association recommends limiting the amount of added sugars to no more than 100 calories per day, or about 6 teaspoons (24 g) of sugar, for women. For men, stick to 150 calories or less per day, or about 9 teaspoons (36 g). That’s a drastic cut from the typical American intake of 22 teaspoons (88 g) of sugar a day—about 355 calories! Clearly, added sugars are adding to our waistlines as well.
Another problem with foods high in added sugars is that they’re often nutritionally empty, so including them in your diet likely means you’re missing out on beneficial foods that can improve your health and slow aging. In addition to reducing your added sugar intake, improve your overall dietary picture by eating more whole grains, beans, fruits, and vegetables. Besides being filled with fiber, which can lower your insulin levels, these foods also contain complex carbohydrates, which take longer to break down and cause a more gradual rise in blood sugar while still providing energy to cells.