In my current practice, patients frequently ask about medications to lose weight. If I’m honest, I don’t like prescribing them. In my experience, patients beg for these medications and often do lose a few pounds when first started, but more often than not the weight comes back once the medicine is discontinued and underlying issues are never really addressed. I also feel these medications are prescribed too liberally in general as an “easy fix” when they are certainly not. 

In 2017, the American College of Endocrinology and American Association of Clinical Endocrinologist updated their recommendations for diabetes management to include considering weight loss medication for overweight and obese patients to help prevent or control diabetes. This makes sense because we know in at-risk overweight or obese individuals with diabetes or prediabetes, weight loss can be beneficial. Because of these recommendations, I have been more open to prescribing them for the appropriate patient. However, I still find most people feel it’s going to be a “magic pill” for them. In this post, I want to share some basic information about some of the more common weight loss medications available on the market today and who might benefit from them. 

How do weight loss medications work?

Each class of medication works differently. Many are very expensive, and some are only approved to take for a short period of time while others can be taken indefinitely. Side effects of these medications are common and may include nausea, diarrhea, headaches, drowsiness, and anxiety among others. Some of them are stimulants that suppress appetite, like Phentermine, which has been around the longest and is probably the most frequently requested in my practice because it’s the most affordable. The drug Orlistat slows down a particular digestive enzyme, causing you to simply not absorb as many calories (and because those calories have to go somewhere, for many this causes diarrhea so severe the medicine has to be stopped). Qsymia is a combination of phentermine and topiramate, which is a neuro-stabilizer and possibly works in the brain to make you feel more full. Belviq works on serotonin and may target hunger receptors in the brain. Contrave is a combination of two drugs, bupropion and naltrexone, which historically have been used to treat depression, smoking cessation, and opioid dependence. Saxenda is a once-weekly injection that mimics a hormone naturally produced in the body which stimulates satiety, or fullness. A similar drug was originally marketed as a diabetes medication that helps lower A1C, and when patients were successfully losing weight it was basically repackaged as a weight loss medication.

All of these medications are intended to work with lifestyle modifications to help promote weight loss. They aren’t “magic pills.” In fact, the average weight loss for any of these medications only ranges from 5 to 10 pounds when compared to placebo. There are also many side effects to consider and some patients are not candidates for specific drugs based on other health conditions they may have.

Who is a good candidate for weight loss medication?

Studies show us that weight loss becomes very difficult because the body adapts to lifestyle changes. When you lose weight, even if you’re obese, the body thinks something is wrong and fights to prevent further weight loss by slowing metabolism and increasing hunger, which prevents further weight loss or in many cases causes rebound weight gain. See my previous post on the Set Point Theory or read this study for more information. Weight loss drugs may help fight this adaptation. So an ideal candidate may be an overweight or obese individual who has successfully lost weight but has plateaued and started regaining some of that weight despite diligent healthy eating and exercising. In this individual, the medication may help fight the body’s desire to regain weight in response to recent weight loss.

Before I prescribe a weight loss medicine, I have to see that the patient is making an attempt to make positive changes on their own. If they have made significant changes but had very little results, or if they had results and have plateaued short of expected results, I may consider it. For example, I had a patient recently who was morbidly obese with pre-diabetes and elevated cholesterol. For the last year, he has been working out 6 days a week and made significant improvements in his diet, cutting out sodas and eating less sugar and more fruits and vegetables. While some of his labs have improved, he’s had zero weight loss. He’s happy to see some of his blood work improving, but with a BMI over 50 his physical mass limits him from being able to do things he wants to do.  This may be a patient I consider trying medication for a short period of time then reevaluating. (We also had the discussion about overexercising and undereating, which is a post for another day).

For most insurance plans to cover weight loss medications, you have to have a BMI above 30 or a BMI from 25-30 and a comorbidity such as high blood pressure, high cholesterol, or high blood sugar. I have many patients with a BMI in the overweight category of 25-30, but otherwise are healthy. Having a BMI under 30 is not directly linked to health problems the way obesity and morbid obesity is so in this case I try to focus more on healthy habits. If your BMI is 28 but you’re eating well and exercising regularly, it’s very likely your body is perfectly happy and healthy at that weight.

In my experience, patients who take the medication to “jump start” their weight loss, almost always regain the weight back. I’ve had patients request weight loss meds and when I review their chart, find they have been on them 3 or 4 times in the past and lost weight, stopped the medication, then gained the weight back in a vicious cycle multiple times over. We then have a conversation that losing 5-10 pounds followed by gaining it back over and over again is not benefiting their health and can be very emotionally taxing.

The bottom line is, none of these medications are beneficial without making other positive lifestyle changes and they should be reserved for a specific subset of people who really need to lose weight for health purposes and are struggling to do so. I’ve yet to see anyone lose a significant amount of weight and keep it off with medication alone, and the most significant weight loss results I’ve seen have been patients who were not taking these medications. My preference when addressing obesity is to focus on sustainable lifestyle changes, which are going to have a much more significant impact on overall health than weight loss medication. These medications do have their place in the comprehensive treatment of obesity, but it’s one piece of the complex puzzle and I encourage people to keep their eye on the big picture.