I haven’t written yet about the new weight loss medications that are sweeping through society (Ozempic, Wegovy, Mounjaro, Zepbound, etc) but that’s not for lack of experience with them. Patients frequently ask me about these medications and yes – I do sometimes prescribe them. Given that interest in these medications is only growing, I thought it was about time to create a blog post on the topic.
The first thing to acknowledge about these medications is that they absolutely work. The vast majority of people who go on them lose weight, often a substantial amount. Given that obesity is a driver of many chronic illnesses, and that weight loss is truly difficult for most people, this alone makes these medications worthy of serious consideration. I want to acknowledge this fact up front, because I’m going to spend much of this post delving into the concerns I have around these meds. But that’s not because I believe these medications should never be used or that they can’t be helpful. It’s just that, given all of the hype about them, my experience has been that patients are often very gung-ho to try these drugs without having first considered the potential downsides. I hope that this post will help the reader gain a more nuanced understanding of these medications and approach them with a bit of caution.
What then are the downsides? There are a number of them, as follows:
The medications only work while taking them. Both in my experience, and in multiple studies, the weight that is lost largely comes back once a patient stops taking the medication. I lead with this concern because, frequently, patients will state they want to go on these medications short-term “just to get me unstuck.” But these medications really don’t work that way. If you go on them, it should be with the assumption that it will be for the rest of your life.
Relevant to the above, many patients who go on the meds will eventually develop distressing side effects and go off the medication. The most common of these side effects include very severe gastrointestinal distress (abdominal pain, nausea, a complete loss of appetite that is truly disabling) and a low level feeling of depression that leaves people feeling flat and joyless. These side effects are in fact the other side of the coin of how these medications work – by inducing a sense of fullness and a loss of interest in food, the medications lead to weight loss, but these feelings can easily go too far and become very unpleasant. This is not necessarily a big deal when it occurs within the first few doses of taking the medication, but I’ve had a number of patients who start to experience these side effects after they’ve done well on the medication for a period of months or longer. The result, predictably, is that they lose weight for a while, feel forced to stop the medication, and then rapidly regain most if not all of the weight they have lost, which of course is frustrating and, arguably, less healthy than if they had never gone on the medication to start with.
Another major concern is that these medications do not discriminate between fat and muscle when stripping off weight, and many people who go on them – especially those who do not make a very concerted effort to pair the medication with a high protein diet and regular resistance exercise – lose a lot of muscle mass. This doesn’t happen to everybody, but I’ve had a few patients whose body composition scans reveal that the majority of their weight loss occurred via muscle. Thus, a not uncommon clinical scenario is that a patient goes on one of these medications for a few months, during which they lose say 40 pounds – 15 pounds of fat and 25 pounds of muscle. Then for whatever reason they stop taking the medication, and quickly regain most of the weight, except this time mostly in the form of fat, i.e. they gain back 30 pounds of fat and only five pounds of muscle. The result is that they are demonstrably worse off than if they had never taken the medication to begin with.
Finally, on the topic of taking these medications for life, is the subject of “unknown unknowns” (to reference the late poet Donald Rumsfeld). Which is to say that while we know of the above side effects and a few others (for example and increased risk for acute pancreatitis, and a possible very slight increased risk of a rare type of thyroid cancer), we really have no idea what happens to somebody if they stay on one of these medications for ten, twenty, or thirty years. They simply haven’t existed long enough for us to have a sense of whether there are any problems associated with such long-term use.
For all of these reasons, I counsel patients to be careful about starting one of these medications, and that they will almost certainly be better off taking the more “natural approach” of changing their diet and exercise habits if they can find success that way. Moreover, I stress to them that these healthy habits do not become less important if one goes on the medication and that the best results, by far, are achieved in those who are combining the medications with an intentional approach to diet and fitness.
