Objective: To assess the prevalence of clinically significant weight loss among women and whether this is associated with smaller long-term weight gains.
Design: Six-year follow-up of young and middle-aged women in the Nurses' Health Study II.
Subjects: A total of 47,515 women who did not report a pregnancy, or a diagnosis of cancer or cardiovascular disease any time between 1989 and 1995.
Measurements: Self-reported weights in 1989, 1991, 1993 and 1995, dietary intake, physical activity, inactivity, history of weight cycling and smoking.
Results: Between 1989 and 1991, 9% of the women lost > or =5% of their 1989 weight (6% lost 5--9.9% and 3% lost > or =10%). The proportion who lost > or =10% of their weight increased with category of body mass index (BMI, kg/m(2)) from 0.4% among women with a BMI <22 to 9% among women with a BMI > or =30 in 1989. Women who lost > or =5% of their weight between 1989 and 1991 gained more weight between 1991 and 1995 than their peers and the difference increased across categories of BMI in 1989. However, due to their large weight losses, women who lost > or =5% of their weight between 1989 and 1991 overall gained less weight than their peers between 1989 and 1995 (P<0.001). Moreover, women who engaged in 5 or more hours per week of vigorous physical activity gained approximately 0.5 kg less than their inactive peers (P<0.001).
Conclusion: Although most women who lost a clinically significant amount of weight regained most of it, they gained less weight over the entire 6 y period than their peers.