It is a well known fact that menopause is often accompanied by unwanted weight gain.  In my clinical practice as an endocrinologist, I meet many women struggling with this exact issue.  While we are far from understanding all of the exact mechanisms involved in this weight gain, there is much that we do know about it, and a recent study brings us one step closer to understanding the intricate steps involved.

At the time of menopause, the reproductive function of the ovaries cease, and with that, levels of estrogen, progesterone, and testosterone naturally decline to low levels.  As these hormones (particularly testosterone) are involved in maintaining lean body mass, one change that we seen in menopause is an increased tendency towards increasing fat mass and decreasing muscle mass, even if the total body weight remains stable.  We also see an increased predisposition towards accumulation of ‘visceral’ fat, which is fat surrounding the abdominal organs.  Visceral fat is metabolically active fat, and therefore associated with a higher risk of developing conditions such as diabetes, high blood pressure, high cholesterol, and heart disease.

Further to that, it is also thought that the natural estrogen deficiency that occurs with menopause may cause weight gain by promoting increased food intake.  Studies in rodents and humans suggest that estrogen supplementation may decrease food intake, as well as increase metabolic rate (the latter may be due to the effect on muscle mass described above, as muscle burns more calories per kg than fat).

An interesting study published by SS Dhillon and colleagues in the International Journal of Obesity brings us one step closer to understanding how estrogen may inhibit food intake.  In a study of rodent neuronal cell cultures from the hypothalamus (one of the key areas of the brain involved in regulation of food intake), it was demonstrated that estrogen decreased the secretion of a hormone called neuropeptide Y, which is the most potent known hormonal stimulator of food intake.  Therefore, the natural loss of estrogen production at and after menopause may result in loss of suppression of neuropeptide Y, thereby leading to increased hunger, increased food intake, and weight gain.  This hypothesis, based on the above study, now needs to be explored further to see if it holds true in humans.

So, what might this mean for the woman who is combating weight gain during and after the menopausal transition?  Well,  it is my firm belief that understanding these natural changes are the first step towards being better equipped to deal with them.  We do not recommend hormone replacement therapy as the answer, as this has been shown to be associated with an increased risk of potentially fatal diseases, such as heart disease, breast cancer, and blood clots in the legs or lung.  However, maintaining an appropriate level of physical activity is crucially important to maintaining the more metabolically active muscle mass (see my previous blog to find out how much activity is recommended by the new 2011 Canadian Guidelines for Physical Activity).  The increased tendency towards hunger can be countered by actions such as increased attention towards eating small, frequent meals; drinking water before meals; and eating lots of FreeVeg to decrease your overall calorie intake!

Dr Sue Pedersen © 2011

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