2001 Annual Meeting of the North American Association for the Study of Obesity

Gary D. Foster, PhD


January 22, 2002

In This Article


Regular physical activity is the single best predictor of long-term weight loss maintenance. However, regular activity can be difficult to sustain. Two studies presented at this year's conference examined the long-term efficacy of different exercise regimens for long-term weight loss. The first, from the University of Minnesota and Brown University, studied the effects of a high level of physical activity (2500 kcal/wk) on long-term weight loss.[8] Subjects (n = 270) were randomized to either standard behavioral treatment (SBT) incorporating 1000 kcal/wk of physical activity or to a high-physical-activity (HPA) regimen of 2500 kcal. Individuals in the HPA group were also encouraged to seek out social support from friends and family to help them achieve this more intensive level of physical activity. After 18 months, the HPA group achieved a mean activity of 2317 kcal/wk closely approximating its goal (2500 kcal/wk), whereas the SBT group reached 1629 kcal/wk, exceeding its goal (1000 kcal/wk). Of the HPA group, 39% reached >= 2500 kcal/wk of physical activity and 51% reached >= 2000 kcal/wk, compared with 20% and 29%, respectively, of the SBT group. The HPA group lost more weight than the SBT group at 6, 12, and 18 months (19.7, 18.7, and 14.8 lb for the HPA group vs 17.9, 13.4, and 9.0 lb for SBT, respectively). From these results, the researchers suggest that higher levels of physical activity than are typically prescribed for obese patients can be achieved and can prove beneficial for long-term weight loss.

A study from the University of Pennsylvania examined the effects of increasing lifestyle activity on long-term weight loss.[9] In this 2-year study, researchers randomized 116 obese adults (mean BMI 35 kg/m2) to 3 treatment conditions: (1) structured on-site (SOS) exercise; (2) structured at-home (SAH) exercise; and (3) lifestyle (LS) activity. All 3 groups received the same 1200-1500 kcal/d balanced-deficit diet. After 12 weeks, the SOS and SAH groups had a goal of walking 4 times per week for 40 minutes, whereas the LS group was asked to take 2000 steps more than their baseline levels. At 12 weeks, LS participants took an average of 3051 ± 1813 steps above baseline, while the SOS and SAH walked 122.3 ± 63.9 and 161.8 ± 128.9 minutes, respectively. There were no significant differences in weight loss across the 3 groups, a finding consistent with data showing that even high levels of exercise in the absence of caloric restriction only produce minimal weight loss. Data from this study at the 2-year mark will be beneficial in determining the efficacy of different types of exercise for the long-term maintenance of weight loss.


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