I am in perimenopause and thought I'd add these thoughts for those who also are in this BEFORE stage of menopause.
In perimenopause your body is producing TOO MUCH estrogen and this disrupts the thyroid production, thereby lowering your metabolism and rate of weight loss. I am currently having mine monitored and corrected with medicine, so it will have the effect of helping my weight loss as well. For those of you in my situation, I suggest that you AVOID soy products as much as possible because of the estrogen-like effect they have (which is a good thing once you are in menopause) will further hinder your thyroid function (which effects your energy levels as well.