When is a one-pound weight gain a good thing? ANSWER: When you were anticipating a two-pound weight gain.
This week, I saw five patients back for their post-metformin consult. In the course of investigating infertility patients, one common finding is insulin resistance, related to PCOS. One way to try and treat this problem is with a drug called metformin. Typically, I put some patients on metformin after their blood tests come back showing clear insulin-resistance. Other times, busy patients, wishing to skip the tedious three-hour blood test just opt to try the medication empirically, based on the existence of many clues supporting the assertion that she has insulin resistance. Some of these clues include family history of diabetes, weight gain out of proportion to what she eats, fat distribution concentrated around the waist (as opposed to hips and thighs), extreme daytime sleepiness/sluggishness (especially after meals), uncontrolled cravings for carbs and sweets, issues with facial hair, and of course, irregular menses and infertility.
I almost always bring patients back for a discussion after trying them on the medication for three weeks. Approximately 80% of the time, patients describe some success with the metformin. They notice increased energy, decreased cravings for carbs and sweets, weight loss, a noticeable slimming of their waistline, and possibly resumption of normal periods. The other 20% report no benefit and are usually discontinued off the medication.
When I pick up the chart on these patients who are returning after a 3-week trial of metformin, the first thing I glance at is their weight and the comparison to their weight BEFORE starting the medicine. If someone had a 10-pound weight loss during the three weeks, I can usually anticipate a discussion in which they will beam with excitement about the changes in their carbs cravings. If someone gained weight or stayed the same during this time, I can usually anticipate them to report no change in their carbs cravings and possibly just the usual bad side effect, which is bad diarrhea.
This week, something odd was happening. Some patients were coming back with negligible weight loss or even slight weight gain, but they were still raving about how great the metformin was, in helping them avoid cookies and soda. It didn’t make sense, because it stands to reason that if a person who usually eats a lot of carbs and sweets can drastically cut down their intake, then they should expect to lose weight. The mystery was solved after one patient elaborated. She had actually gone up from 149 pounds to 150 pounds in three weeks. But she was raving about how the metformin had wonderfully taken away her previous intense cravings. Whereas she used to absolutely require a cookie or soda 2 hours after lunch each day, she now had no desire for such junk. She reported that the difference was like night and day. When I expressed some surprise that despite this change, she had gained one pound, she explained that near Thanksgiving, she had participated in three big feasts, one with her family, one with her in-laws and one at work. Each year, she said, Thanksgiving would see her with a gain of four to five pounds easily. So the fact that she gained only one pound this year was not a minor setback, but a major victory!
In the future, I will remember to take into account the Thanksgiving Effect when assessing the success or failure of metformin.
