As obesity rates have significantly increased lately and consequently the number of obesity-related diseases, researchers are trying to find ways to help people lose weight and keep it off.

The last study on this subject was led by John M. Jakicic, PhD, of the University of Pittsburgh and his colleagues and published in the July 28 issue of the Archives of Internal Medicine journal.

According to their findings, obese and overweight women need to cut calories and exercise minutes 275 minutes a week or at least 55 minutes a day five days a week to lose weight and keep it off, which means 25 minutes more than the current recommendation of the government.

“Somewhere between 50 and 60 minutes, five days a week is a target for people who have lost weight and are trying to keep that weight off,” Dr. Jakicic said.

For the study, he and his colleagues followed 201 overweight and obese women from 1999 to 2003. The women were told to eat 1,200 to 1,500 calories a day and were divided in four groups.

The first two groups were asked to burn the equivalent of 1,000 calories a week by either moderate exercise or vigorous exercise. The other two groups were asked to burn 2,000 calories either by either moderate exercise or by vigorous exercise. Approximately 30 minutes a day, five days a week, of brisk walking should burn about 1,000 calories, Dr. Jakicic said.

Although all the women had lost an average of between 8 and 10 percent of their body weight after six months, most could not keep the extra pounds off. It seems that it is easy more easy to lose weight than maintain after.

About 26.5 percent of women succeeded to maintain the weight loss at the end of the two-year follow-up period. When analyzing their daily program of exercise, the researchers found that they exercised an average of 275 minutes a week, the equivalent of burning 1,835 calories. These women also completed more telephone calls with the intervention team and engaged in more eating behaviors recommended for weight control such as a lower intake of dietary fat.

The researchers concluded the study “clarifies the amount of physical activity that should be targeted for achieving and sustaining this magnitude of weight loss, but also demonstrates the difficulty of sustaining this level of physical activity. Research is needed to improve long-term compliance with this targeted level of physical activity.”

According to data of the US government, about 35 percent of women in the US are obese, which puts them at a higher risk for high blood pressure, diabetes and heart disease. Worldwide, diabetes affects an estimated 246 million adults and accounts for 6 percent of all global deaths. Type 2 diabetes, which is linked to obesity and physical inactivity, accounts for about 90 percent of all diabetes and the situation is expected to get worse as more developing nations adopt French fries and other Western-style fast foods. The International Diabetes Federation estimates there will be about 380 million people suffering from diabetes by 2025.