Oct. 3, 2005 -- Want to keep extra weight off as you age? You might want to develop a strategy that lasts a lifetime.
In a lengthy study, many people who had a normal body mass index (BMI) in middle age eventually became overweight, and some became obese.
Consider these before-and-after results:
- Between a tenth and a quarter became overweight in just four years.
- More than half became overweight in 30 years.
The study appears in the Annals of Internal Medicine. The researchers included Ramachandran Vasan, MD, of the Framingham Heart Study.
Vasan's study included more than 3,700 white men and women who were enrolled in the Framingham Heart Study.
Participants had their BMI measured at least twice, four years apart, during the 30-year study.
Middle-aged men packed on weight relatively quickly. Over four years, more than a quarter of the men with normal BMI became overweight. For men with normal and overweight BMI values, up to 9% became obese in four years.
A smaller percentage of women (14% to 19%) became overweight in four years' time. Between 5% and 7% of normal and overweight women became obese in four years, the study shows.
As the years gathered, so did the pounds. Here are the results over 30 years:
- More than half of all participants became overweight.
- About a quarter of participants became obese.
- 1 in 10 participants became severely obese.
Over the long haul, similar percentages of men and women became overweight or obese. People who were overweight when the study started were more likely to become obese.
"These estimates suggest that the future burden of obesity-associated diseases may be substantial," write the researchers. However, their report doesn't give details on participants' health.
BMI is calculated from height and weight. It isn't a perfect measure of fatness.
For instance, people often lose lean body mass as they age. That can raise body fat percentage while leaving BMI unchanged, the researchers note. Resistance training is one way to maintain or build muscle mass.
BMI also doesn't reflect shifts in the location of body fat. Past research has linked fat around the waist to health problems including heart disease and diabetes. It's not clear if that fat causes or just accompanies those problems.
The study only tracked weight gain starting in middle age. Other age groups might have different results, write the researchers.
Lastly, since all participants were white, results aren't known for other racial and ethnic groups.
Diet crazes come and go. Many health experts recommend making lasting changes instead of following the latest diet fads.
Your doctor can give you pointers. The U.S. government recommends these general steps for healthy living:
- Get at least 30 minutes of physical activity five or more days per week.
- Choose whole grains for at least half of the grains you eat.
- Eat a mix of five to nine servings of fruits and vegetables daily.
- Favor lean sources of protein (including leaner cuts of meat and poultry, fish, and beans).
- Choose low-fat or fat-free dairy products.
- Cut back on foods containing saturated fat, trans fats, and cholesterol.
Don't forget about calories. You've got to burn more calories than you consume to lose weight, so make your choices wisely.