Why do we focus on diabetes in a book about heart disease? Because people with diabetes have an especially high risk of developing heart disease. If they do get heart disease, their heart problems tend to be worse than those in people without diabetes.

In addition, people with diabetes have five times the risk of having a heart attack that non-diabetics do. In fact, research has shown that simply having an elevated blood sugar level even without diabetes is a risk for heart disease.

A large United Kingdom study involving more than 5,000 people with diabetes found that for every 1 percent reduction of HbA1c, there was an 18 percent reduction in heart attacks and a 25 percent reduction in all diabetes-related deaths. The reasons are fairly simple.

First, people with diabetes often have high LDL (bad) cholesterol levels and low HDL (good) cholesterol levels, both of which lead to faster rates of atherosclerosis. Second, they also tend to have high blood pressure, in part because they are overweight. Third, they have a greater tendency to form blood clots. And finally, they have a higher likelihood of inflammation in the blood, which is closely linked to increased heart disease risk.

Strategies for Controlling Blood Sugar

If you have heart disease, it’s critical to control your blood sugar levels. It’s that simple because the link between high blood sugar and more severe heart problems is that clear. The good news is that even if you have what’s known as “borderline high” blood glucose levels, are overweight or obese, or have a family history of the disease, you can prevent yourself from developing Type II diabetes.

And if you already have it, you can control it. Oddly enough, the strategies for getting your blood sugar levels under control, or keeping them under control, are the same as the strategies we’ve seen in other sections of this book: diet, weight control, and exercise—and if those are not sufficient, medications.

Diet

It was once thought that people with diabetes should avoid eating anything sugary, but there was never any scientific evidence to support this conclusion. Since almost everything you eat eventually is converted to sugar (glucose) anyway, what matters most is that you regulate the number of calories you eat.

Eating a large quantity of a simple carbohydrate, such as potatoes, bread, or rice, can indeed quickly load your bloodstream with glucose. The answer for most people isn’t to stop eating such foods, but to control how much of them you eat. How much is too much?

That’s something you and your doctor will work out based upon your glucose tests. But as a general rule, the American Diabetes Association says simply that you should maintain a diet that is low in calories, low in fats, and well balanced nutritionally. Still crave something sweet? Artificial sweeteners can help make a fine substitute.

These basic nutritional guidelines will reduce your blood sugar to acceptable levels if you follow them closely. Some nutritionists and doctors nonetheless believe you should limit your intake of foods with what is known as a high “glycemic index”—that is, foods that will rapidly increase sugar levels in your body after you eat them.

The glycemic index is a relative scale of how fast circulating blood sugar rises after the consumption of a certain carbohydrate. The top of the scale is 100, which is the value for glucose itself. The glycemic load is a measure of the full impact of the carbohydrate, taking the glycemic index into account.

The glycemic load is the glycemic index divided by 100 and multiplied by the available carbohydrate content (carbohydrate minus fiber) in grams. A glycemic load of 20 or more is considered high. There is some obvious logic to this approach; after all, consuming quantities of these foods simply makes it harder to control your blood sugar levels.

But the long-term effects of following a diet based on the glycemic index are still unclear and consequently the American Diabetes Association guidelines do not currently endorse using the glycemic index. However, research in this area is growing, and many doctors and patients, betting that future studies will show benefits of using the glycemic index, are tailoring their diets accordingly.

Weight

Being obese or overweight, especially if that weight consists significantly of abdominal body fat, is closely linked to insulin resistance. That’s the bad news. The good news is that research shows that losing this weight lowers that insulin resistance.

Moderate weight loss, on the scale of 10 to 20 pounds, has been shown to lead to lower glucose levels, cholesterol, and blood pressure—all outcomes that reduce your risk of heart disease. Of course, losing weight and keeping it off is seldom easy.

Exercise

For people with high glucose levels, exercise alone can have a remarkable effect. For reasons that are not entirely clear, it appears that regular exercise can reduce insulin resistance in cells, increase glucose absorption, and, as a result, decrease glucose levels in the bloodstream.

This effect works best for people who have good glucose control and are taking oral anti-diabetic medications, but the benefits of exercise for all people with diabetes or borderline high glucose are clear. An analysis of multiple studies shows that regular exercise training over the long term can lower HbA1c levels close to 1 percent, regardless of what diabetic treatment the patient is following.

Studies also show that people with diabetes who exercise at least two hours per week have a 40 percent lower risk of heart disease or stroke. Of course some people with diabetes have conditions that limit their ability to exercise (blood vessel disease, loss of circulation or sensation in the feet, heart disease), so you should ask your doctor what kind of exercise program would best suit your needs.