The current study suggests that women who gained more weight since menopause are at greater risk to be unsuccessful in their weight loss attempt (with caloric restriction) within a few years after intervention. Therefore, weight gain during the menopause period has to be monitored closely because it may be hard to successfully lose those extra pounds and keep them off after menopause.
The fact that initial fat mass, lean body mass, and RMR were associated with body weight regain is not novel.6
However, with this study we add another variable that needs to be taken into account when evaluating the risk of weight regain following a caloric restriction in postmenopausal women. Several studies have reported an association between loss in lean body mass and decrease in RMR after weight loss.24
Surprisingly, we observed no overall decrease in RMR after the intervention despite significant decreases in lean body mass. It is likely that the mean lean body mass loss of 1.3 ± 1.3 kg or 3.2% in the present study might be statistically significant but clinically trivial. In fact, Busetto et al25
reported a mean lean body mass loss of 9.4%, while we only observed a mean loss of 3.2%. Consequently, the observed difference between study results could be explained by the magnitude decrease in lean body mass during weight loss intervention.
From a clinical point of view, the fact that weight gain since menopause might be an important component of weight regain after a caloric restriction intervention is of great interest considering that more than 50% of women in the menopausal period try to lose weight without successful maintenance.4
Determining how much weight was gained since menopause, as one of the variables that predicts weight loss maintenance, could be useful since that information is easy to get. A question asking women how much weight they gained since menopause may be too simple and invalid but a study conducted by Lawlor et al22
concluded that self-reported and measured body weight are highly correlated in older adults (r
= 0.98). Thus, women who report gaining a large amount of weight since menopause should have a tight follow-up to favor weight loss maintenance. In 2005, the Obesity Society and the American Society for Nutrition stated that innovative studies are needed to identify and better understand factors associated with weight loss maintenance in older individuals24
and this study, with some reservations, goes exactly in that direction.
As this study was exploratory and based on a small sample, many limitations of this study must be mentioned. First, the lack of a control group and the small sample size affect the external validity of the results. Consequently, results translate only to obese postmenopausal women aged between 50–75 years. Second, weight gain since menopause was evaluated with a single question. Thus, objective measure of lifetime body weight would be needed to validate the results. Moreover, we do not have the obesity status before menopause which could impact on the association between weight gain since menopause and weight regain. Similarly, some may argue that age of menopause can also play a role in this association. However, we can partially rule out this hypothesis since we observed no significant correlation between weight loss maintenance and the duration of menopausal status (r = 0.37; P = 0.11). Third, because of the study design, it is not possible to investigate mechanisms or other variables that may help to understand our results. Despite these limitations, we need to highlight that these results are based on a well-characterized sample of obese postmenopausal women and the limited number of subjects allowed us to closely follow the participants. Nonetheless, our results are really intriguing and need to be confirmed with a tighter design and objective methods to assess the exact time of menopause as well as a measured follow-up of body weight since menopause.
In conclusion, our study suggests that greater weight gain since menopause is correlated with lower weight maintenance after a caloric restriction intervention in obese postmenopausal women. Indeed, weight gain since menopause could be considered a variable to identify postmenopausal obese women at greater risk of weight regain after a caloric restriction regimen. Despite this intriguing finding, further studies are needed to validate our results.