Small Weight Changes Mean Big... Health Article

Research shows that if you are overweight or obese, a little weight loss goes a long way toward reducing your risk for disease and protecting your health.

You are overweight if your body mass index (BMI) is 25 to 29, and obese if your BMI is 30 or greater. BMI is a measure of body weight adjusted for height. BMI is closely associated with body fat. The relationship between body fat and BMI differs with age and gender, according to the Centers for Disease Control and Prevention (CDC). Women, for instance, are more likely to have a higher percent of body fat than men.

Overweight or obese people "who lost just 5 to 10 percent of their body weight showed measurable and significant improvement in terms of managing and preventing type 2 diabetes, hypertension, heart disease and osteoarthritis," says Wahida Karmally, Dr. P.H., R.D., a spokeswoman for the American Dietetic Association (ADA) and director of nutrition at Columbia University's Irving Center for Clinical Research in New York City.

Evidence also shows that modest weight loss may reduce the risk of some types of cancer.

Preventing cancer

A study of 900,000 adults published in the New England Journal of Medicine in 2003 found that men and women with highest BMI were more likely to die of cancer of the esophagus, colon and rectum, liver, gallbladder, pancreas and kidney. They were also more likely to die of non-Hodgkin's lymphoma and multiple myeloma. Men with a high BMI also were more likely to die of cancer of the stomach and prostate. Women with a high BMI also were more likely to die of cancer of the breast, uterus, cervix and ovary.

Overall, the study estimated that excess weight accounts for 14 percent of cancer deaths in men and 20 percent in women in the United States.

At the core of the issue for cancer and other chronic diseases is body fat. Once considered benign "padding," fat now is regarded as metabolically active tissue that produces enzymes and hormones that may interfere with body functioning and set the body on an altered course, Dr. Karmally says.

Beating heart disease

A person who has a BMI of more than 25 is at increased risk for heart disease, and high blood pressure is twice as common in adults who are obese than in those who have a healthy weight, according to the Surgeon General.

High blood pressure (greater than 140/90 mm Hg) can increase your risk for stroke, heart attack and kidney damage.

Although medication is available to treat blood pressure, losing just a little over 5 percent of body weight can have the same effect as a single dose of hypertensive medication, says Dr. Karmally. "Studies also suggest that some people who lose weight may be able to stop taking blood pressure medication."

"In addition to its beneficial impact on blood pressure, a 5 to 10 percent weight loss can help improve blood cholesterol levels and lower triglycerides, a form of fat your body makes and gets from food that provides energy, insulates organs and transports fat-soluble vitamins," says Dr. Karmally.

Derailing diabetes

Gaining 11 to 18 pounds boosts the risk for developing type 2 diabetes to twice that of a person who has not gained weight, the Surgeon General says. In fact, more than 80 percent of people with type 2 diabetes are overweight or obese.

Losing weight can reduce your risk for diabetes by reducing insulin resistance or impaired glucose tolerance, both of which can lead to type 2 diabetes. Even if you've already been diagnosed with type 2 diabetes, weight loss can help lower circulating blood glucose levels.

"Studies have shown that some people who lose even small amounts of weight can go off diabetes medications," says Dr. Karmally.

Other health problems

• A person who is obese is at higher risk for breathing problems such as sleep apnea and asthma.

• Women who are obese may have more difficulties in pregnancy. Obesity increases the risk for high blood pressure during pregnancy by 10 times, and boosts the risk for gestational diabetes. The risk for birth defects also increases in obese women. Women who are obese often have more difficult labor and delivery. Infants born to obese women are more likely to have a high birth rate and low blood sugar, which as been linked to brain damage and seizures.

• Women who are obese may have irregular menstrual cycles and fertility problems.

• People who are overweight or obese are at higher risk for gallbladder disease, incontinence and depression.

• For every two-pound increase in weight, the risk for developing arthritis increases by 9 to 13 percent, according to the Surgeon General.

Losing it for good

Still, to reap the health benefits of modest weight loss, you can't just lose it. "To promote good health, you have to maintain your weight loss," says Dr. Karmally.

To keep weight off, experts recommend aiming to lose just 10 percent of your body weight by burning or cutting 3,500 to 7,000 calories (the equivalent of one to two pounds) per week more than you consume over the course of six months. Even clinically obese patients are advised to stick to that humble objective.

"It's just not possible for most people to lose more," says Gary Foster, Ph.D., clinical director of the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine in Philadelphia. "And even if you could, studies suggest you'll be more likely to gain it back."

If you're able to keep the weight off for six months, then you can try to lose more. And although one or two pounds a week doesn't sound like much weight loss, it's the healthiest way to burn fat without compromising calorie-burning muscle.