A Dietitian's View

Family history: I always assumed that because many in my family had died from heart disease, I was in trouble. But it turns out that what really matters is early heart disease — for men that means a heart attack before age 55 and for women, age 65. Even then, only first-degree relatives — parents, children, and siblings — are considered red flags. And while it's true that type 2 diabetes rarely occurs in people who aren't overweight or obese, the risk of developing the disease is 5 to 10 times higher if a first-degree relative has it — regardless of your weight.

As far as the big C is concerned, only about 5 percent to 10 percent of cancers are inherited, and those that are typically occur earlier in life. According to the American Cancer Society (ACS), most cancers are caused by gene mutations brought on by age, lifestyle, and environmental factors, like inactivity, smoking, excessive alcohol consumption, and increased exposure to radiation or carcinogenic chemicals, among others. In fact, researchers from Britain's Million Women Study found that 5 percent of all cancers affecting postmenopausal women in the United Kingdom are associated solely with excess body weight. Indeed, the ACS and the NCI acknowledge that while being overweight and obese are linked to an increased risk of cancer, there is limited evidence that losing pounds will reduce that risk.

Waist measurement: For women, a waistline of 35 inches or larger is a risk factor for heart disease, no matter how much you weigh or how trim your arms and legs are. And a measurement of 31.5 inches or more indicates an elevated risk of some cancers.

Fitness: Walking briskly for 30 minutes, five days a week, is enough to protect you from disease, no dieting required. "Fitness is achievable, and may do more to improve health than simply losing weight," says Steven Blair, PED, a professor of exercise science at the University of South Carolina and a leading expert on the benefits of exercise among the overweight. In fact, a recent study from the university tracked 2,600 people age 60 and older for a 12-year period, and found that fit overweight people outlive unfit normal-weight people. (Score one for me!) However, if you're overweight and it hurts just to walk up and down stairs, weight loss may be called for; obese women are 4 times more likely to develop knee osteoarthritis than normal-weight women.

Cholesterol and inflammation: A total cholesterol level of 200 mg/dL or more, an HDL reading of less than 40 mg/dL, or triglyceride levels above 150 mg all point to trouble. Being overweight tends to increase cholesterol, and losing weight can help lower total and LDL levels, while raising HDL levels, according to the National Heart, Lung, and Blood Institute. (So can increasing your daily activity if you're sedentary.)

Many experts feel that your rate of systemic inflammation, as defined by the results of a C-reactive protein (CRP) test, is an even stronger indicator of heart disease risk. Being overweight raises your risk of inflammation.