Successful weight loss in obese individuals is defined as a reduction of 10 percent or more of initial body weight maintained for at least a year. The jury is still out, however, as to whether fast or slow initial weight loss is the best approach for long-term weight control in obese patients.
On the one hand, there is evidence that losing weight slowly initially results in continued weight loss, reduced risk of weight regain, and successful long-term weight loss maintenance. On the other hand, it has also been shown that the greater the initial weight loss in obese patients, the larger the total weight loss observed longer term.
The new study examined the association between rate of initial weight loss and long-term maintenance of lost weight, by looking specifically at whether losing weight at a slow initial rate results in larger long-term weight reduction and less weight regain than losing weight at a fast initial rate.
Researchers analyzed data for 262 middle-aged obese women who took part in the Treatment of Obesity in Underserved Rural Settings (TOURS) trial. These women followed a six-month lifestyle program encouraging them to reduce their calorie intake and increase their moderate intensity physical activity to achieve an average weight loss of 0.45kg per week. They were then supported for a further year with an extended care program involving contact twice a month in the form of group sessions, telephone contact or newsletters.
The women were split into three groups according to how much weight they lost in the first month of the intervention. Women in the FAST group lost over 0.68kg per week; those in the MODERATE group lost between 0.23 and 0.68kg per week; women in the SLOW group lost less than 0.23kg per week in that first month. The authors then looked at the womens' weight loss at 6 and 18 months, as well as any weight regain.
There were long-term advantages to fast initial weight loss. Fast weight losers lost more weight overall, maintained their weight loss for longer and were not more likely to put weight back on than the more gradual weight losers. In particular, women in the FAST group were five times more likely to achieve the clinically significant 10 percent weight loss at 18 months than those in the SLOW group and those in the MODERATE group were nearly three times more likely to achieve this milestone than women in the SLOW group.
Citation: Lisa M. Nackers, Kathryn M. Ross, Michael G. Perri, 'The Association Between Rate of Initial Weight Loss and Long-Term Success in Obesity Treatment: Does Slow and Steady Win the Race?', International Journal of Behavioral Medicine, 2010; doi: 10.1007/s12529-010-9092-y