Weight Loss Drugs Should Be Taken With Diet and Exercise

6 min read

Feb. 8, 2024 -- New and effective weight loss drugs have been a game changer for people with obesity or who are overweight with a related health condition. But patients taking these drugs should not neglect diet and exercise, experts say. 

In approving GLP-1 medications such as Wegovy and Zepbound, the FDA has specified that patients taking these medications should also maintain proper nutrition and get regular exercise. 

Many patients receive prescriptions for these GLP-1 drugs without being advised to modify their lifestyles. One reason is that the primary care doctors who often prescribe the medications aren’t necessarily trained in obesity medicine and lack the time to educate patients, said Katherine Saunders, MD, an obesity expert at Weill Cornell Medicine and a co-founder of Intellihealth, a software and clinical services company specializing in obesity care.

Saunders says she has seen GLP-1 drugs being prescribed “without any structure." 

"That’s problematic," she said. "We can’t prescribe these medications in a vacuum, without education or support. We have to find out what each patient’s situation is. What’s their baseline diet and baseline exercise, what are they willing to do?”

She stressed that obesity is a varied and "complex chronic disease that requires personalized treatment. The answer is not a one-size-fits-all approach. So it’s important to do a comprehensive evaluation and to design tailored treatment plans.”

Gary Foster, PhD, chief science officer of the popular weight loss program WeightWatchers, agreed that GLP-1 drugs alone are not enough for people who need to lose a significant amount of weight. 

"While these medications assist individuals with biological challenges in losing weight, they cannot replace healthy eating, increased physical activity, or a shift in mindset --crucial components for enhancing mental and physical well-being and achieving long-term weight management,"  he said. 

WeightWatchers’s new GLP-1 Program “is specifically designed to meet the unique needs of those taking a GLP-1 medication to support essential behaviors such as consuming sufficient protein, opting for fruits and vegetables, maintaining hydration, and establishing a regular activity routine.”

Many Firms Jump In 

Besides WeightWatchers and Saunders’s firm, Intellihealth, many other organizations offer prescriptions for GLP-1 drugs in the context of a weight loss program. Among these are the Mayo Clinic, Noom, Transcarent, and Teladoc -- all of which use telehealth platforms.

The Mayo Clinic recently hired Amwell, a national telemedicine firm, to provide GLP-1 prescriptions to qualifying members of its diet clinic. If a clinic member meets FDA qualifications -- a body mass index over 30 for obese patients or a BMI over 27 for overweight people with at least one weight-related chronic condition -- they can go directly from the Mayo Diet Clinic site to Amwell and make an appointment with an Amwell doctor to get a prescription. Mayo continues to give these members nutritional and other kinds of support.

Mayo also offers support for Diet Clinic members who already have GLP-1 prescriptions, said Tara Schmidt, lead registered dietitian for Mayo Clinic Diet. The clinic’s base program includes six different meal plans, a food tracker, a bar code scanner, and an exercise regimen. Mayo has added a seventh meal plan designed for people who are taking GLP-1 drugs. 

“It is higher in protein, and we made sure to address things like managing side effects and providing adequate nutrition,” Schmidt said. “This is a volume-restricted diet with delayed gastric emptying. So instead of our usual 12-week program, the GLP-1 program lasts for 24 weeks. We’ve added 12 weeks of content related to these medications.”

Nutrition has to be calibrated to both the direct and the side effects of these weight loss drugs, she explained. 

“There are a lot of gastrointestinal side effects with GLP-1s because they delay the rate of gastric emptying, or the rate at which food leaves the stomach. Many people experience nausea, vomiting, diarrhea, and/or constipation. To make sure they get enough nutrition and enough hydration and protein, we remind people that they need to drink frequently and that they may tolerate softer or blended or liquid meals initially better than they would a solid meal. If they don’t stay hydrated, they’re likely to have headaches and fatigue.”

Regular Exercise Is Essential 

It's also key to start or maintain an exercise program when taking GLP-1s, she stressed.  When people are on any kind of diet and lose a lot of weight, part of that lost weight consists of lean muscle mass. “So we encourage members to do strength training — regular physical activity, including strength training — to retain that muscle mass,” Schmidt said. 

Saunders agreed that people need exercise to preserve muscle mass and overall health. She estimates that GLP-1 users can lose about a third of their muscle mass over time unless they exercise regularly.

And if you lose muscle, “it will make it much harder to keep all that weight off, and the metabolic effects of losing muscle can have implications for bone health and metabolic health. When people get older, it can affect balance and make them weaker.”

WeightWatchers emphasizes the psychological aspect of weight loss.  

“These [GLP-1] medications effectively decrease appetite and reduce food ‘noise,’ which we define as constant, intrusive thoughts about food, resulting in substantial weight loss. This means we have to ensure proper nutrition to help with getting enough nutrients to optimize health and well-being," said Michelle Cardel, PhD, the firm’s head of global clinical research and nutrition. 

Starting and Stopping Medications

Despite the difficulty of losing weight through diet and exercise alone, the Mayo Diet Clinic advises people who aren’t yet on medications to try lifestyle modification first. 

“GLP-1 drugs are a stepping stone, just like bariatric surgery. Start with lifestyle, and should you need additional tools or support, we have other options,” said Schmidt.

Spencer Nadolsky, DO, medical director of WeightWatchers, stresses that the company’s clinicians recommend GLP-1 medications only to people who meet the FDA criteria. They may receive these prescriptions after being screened for BMI eligibility and contraindications for GLP-1 drugs. After that, a WeightWatchers doctor may determine that a particular medication would be helpful to the patient, he said. 

Experts estimate that roughly half of the people who start using GLP-1 drugs discontinue them within a year, either because of their side effects or because of the cost. After they stop taking the drug, they usually regain much of the weight they lost. But if they are in a diet program, it can help them keep their weight down even after they stop the medication, Schmidt said. 

“Their thoughts of food are likely to return, and they won’t have that physiologic [i.e., drug] assistance anymore. What can aid in any form of weight loss -- or in this case, prevention of weight regain -- is to do things like self-monitoring, making sure that you stay on a calorie-restricted diet, and maintaining self-awareness. When you step on the scale and see a little bit of weight loss, you’re more likely to do the same thing tomorrow.”

Nevertheless, both Schmidt and Saunders said that people who can benefit from GLP-1 drugs should stay on them for a long time. 

“We’d never expect someone to take a medication for blood pressure or diabetes and stop the medication once their numbers are controlled,” Saunders points out. “We’d say, ‘The medication is working, keep on taking it.’”

Even after a WeightWatchers member achieves their goal weight and transitions to a maintenance dose of their weight loss medication, “they can choose to [continue] with the GLP-1 program. This is because the program is structured to promote health at any stage of the weight loss journey," Nadolsky said. "Remaining on the program during maintenance ensures ongoing emphasis on essential habits, including ample protein intake, incorporating fruits and vegetables, maintaining hydration, and prioritizing daily activity — all important components for overall health.”