Exercise Needed to Maintain Weight Loss in Overweight Women

The current analysis reports on participants' maintenance of weight loss at 24 months as well as the effects of exercise on maintenance of weight loss.

"The importance of physical activity may be heightened in the maintenance of clinically significant weight loss," write John M. Jakicic, PhD, from the University of Pittsburgh in Pennsylvania, and colleagues. "The consensus on recommendations for physical activity is a minimum of 30 minutes of moderate intensity activity on most days of the week, or 150 min/week. There is growing consensus that more exercise may be necessary to enhance long-term weight loss."

Between December 1, 1999, and January 31, 2003, a total of 201 overweight and obese women with no contraindications to weight loss or physical activity were recruited from a hospital-based weight loss research center and randomly assigned to 1 of 4 behavioral weight loss intervention groups according to physical activity energy expenditure (1000 vs 2000 kcal/week) and intensity (moderate vs vigorous).

With a combination of in-person conversations and telephone calls during the 24-month study period, participants were also encouraged to reduce intake to 1200 to 1500 kcal/day. At baseline, body mass index was 27 to 40 kg/m2, and age range was 21 to 45 years.

The intervention groups did not differ significantly in weight loss at 6 months (8% - 10% of initial body weight) or 24 months (5% of initial body weight). Compared with individuals sustaining a weight loss of less than 10% of initial body weight, those sustaining a loss of 10% or more of initial body weight at 24 months reported performing more physical activity (1835 kcal/week or 275 minutes/week; P < .001), based on post hoc analysis.

"The addition of 275 minutes/week of physical activity, in combination with a reduction in energy intake, is important in allowing overweight women to sustain a weight loss of more than 10%," the study authors write. "Interventions to facilitate this level of physical activity are needed."

In an accompanying commentary, Warren G. Thompson, MD, and James A. Levine, MD, PhD, from Mayo Clinic College of Medicine in Rochester, Minnesota, note that dieting is modestly effective for the short-term effect of obesity but that the long-term benefit is still unproven.

"Jakicic et al beautifully demonstrate that sustained weight loss requires the continued achievement of 2000 kcal/wk of physical activity," Drs. Thompson and Levine write. "We believe that 2000 kcal/wk of physical activity can be achieved through a combination of strategies, including increased formal exercise, a modified work and school environment that allows for movement while working and learning, and a modified home environment with less television and more movement. Further research in sustainability of activity is urgently needed if we are to solve the obesity epidemic."

Practice Pearls:

• In a previous report from the current study cohort, higher intensity or duration of exercise was not more effective than moderate exercise in weight loss or cardiorespiratory fitness.
• In the current study of overweight and obese women, the addition of at least 275 minutes/week of exercise to reduced energy intake was effective in maintaining a 10% weight loss at 24 months.

Source: Diabetes In Control: Arch Intern Med. 2008;168:1550-1559, 1559-1560.