In addition to limiting calories, overweight and obese women may need to exercise 55 minutes a day for five days per week to sustain a weight loss of 10 percent over two years, according to a new report released today.
Current recommendations prescribe 30 minutes of moderate physical activity on most days of the week, for a total of 150 minutes per week.
To calculate the amount of exercise needed, John M. Jakicic from the University of Pittsburgh enrolled 201 overweight and obese women in a weight loss intervention between 1999 and 2003. All the women were told to eat between 1,200 and 1,500 calories per day. They were then assigned to one of four groups based on physical activity amount (burning 1,000 calories vs. 2,000 calories per week) and intensity (moderate vs. vigorous).
After six months, women in all four groups had lost an average of 8 percent to 10 percent of their initial body weight. However, most were not able to sustain this weight loss. After two years the women’s weight was an average of 5 percent lower than their initial weight, with no difference between groups.
The 24.6 percent of individuals who did maintain a loss of 10 percent or more over two years reported performing more physical activity (an average of 1,835 calories per week, or 275 minutes per week over the baseline level of activity) than those who lost less weight.
Source: Arch Intern Med. 2008;168[14]:1550-1559.
July 29th: This study has just been disputed on the Weighty Matters blog. Check it out here.