New Advisory Offers First Consensus in Prescribing GLP-1s

Medscape

08-07-2025

Anywhere from 6% to 12% of the US population has taken a GLP-1 agonist. But until now there hasn't been a cohesive message among physicians for how to care for this growing patient population.
Last month the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society released a joint advisory that included a list of nutritional and lifestyle priorities to help physicians guide patients on their weight-loss journey.
Published in late May in the journal Obesity, the priorities included a baseline nutritional assessment, an understanding of patient goals, management of the most common medication side effects, reduced dependence on ultra-processed foods, prevention of nutrient deficiencies, strength training to prevent muscle loss, and other lifestyle factors that might influence weight loss.
'GLP-1s are reshaping the landscape of obesity treatment, but it's clear that medication alone is not a complete solution,' John E. Courtney, PhD, CEO of the American Society for Nutrition, said in a statement. While the medications can powerfully reduce hunger in patients who take them, they work best in conjunction with lifestyle changes, the most important of which is proper nutrition.
An Emphasis on Diet
Primary care physicians need to work with patients to better understand their diet before prescribing these medications, said lead study author and Advisory Chair Dariush Mozaffarian, MD, PhD, director of the Food is Medicine Institute of Tufts University, Boston.
'These medications are approved as an adjunct to nutrition and lifestyle therapy and right now they're being used as a first line in most cases,' said Mozaffarian.
Asking a simple set of questions about what patients eat in a day, whether they snack, and whether they eat out at restaurants can provide physicians with a good idea of a patient's diet pitfalls.
Dariush Mozaffarian, MD, PhD
Other barriers to healthy eating can include cost but also knowledge of how to prepare healthy meals, proper cooking equipment, culture, and food traditions around healthy eating. Additionally, some patients might not live near grocery stores.
A study published last year in the journal Obesity Pillars found that physicians and dietitians can help patients maximize long-term weight loss results by providing them with personalized guidance. For example, apps that can help patients track nutrition and daily caloric intake as well as personalized advice that can help highlight their dietary sticking points.
Additionally, about half of all patients have significant gastrointestinal issues on these medications and eating a healthy, well-balanced diet can help them to stave off some of the most common side effects, including constipation, nausea, and vomiting, said Mozaffarian. This includes tricks of the trade like drinking ample water, eating small meals, getting enough fiber, and avoiding fatty foods. Ramping up dosages of the medications more slowly can also help patients to avoid these symptoms.
Reducing Dependence on Ultra-Processed Foods
'Many patients not only eat less but their preferences for foods change and one of the most common themes is that they no longer crave ultra-processed foods that are very sweet or contain artificial ingredients,' said Mozaffarian. These are the foods that can be high in fat and contain chemicals that make people want to keep eating them.
There's also research to show that ultra-processed foods are increasing some of the comorbidities that go along with weight gain like diabetes and nonalcoholic fatty liver disease.
Some of the chemicals in these foods might also be driving effects on the gut microbiome and intestinal health, said Carolynn Francavilla, MD, a nationally recognized obesity physician who owns and operates Green Mountain Partners for Health and Colorado Weight Care, both in Denver.
Staving Off Nutrient Deficiencies
What's more, some research has shown that many patients aren't getting ample nutrition because their appetite is so suppressed. One study released in April in Frontiers in Nutrition found that patients on GLP-1s were not getting sufficient amounts of fiber, calcium, iron, magnesium, potassium, and choline as well as vitamins A, C, D, and E.
Carolynn Francavilla, MD
Focusing on minimally processed foods can help patients to avoid deficiencies that come with the medications. When a patient's diet is drastically reduced, it can make it difficult to get enough protein as well as essential micronutrients. Carefully planning meals to fit in enough protein as well as fruits, vegetables, and whole grains is a great way to ensure that patients avoid deficiencies.
However, some processed foods, for example, meal replacement shakes and bars might help patients get enough nutrients when they don't have the appetite they once did. 'These should be an exception because for some patients they can help fill in the gaps,' said Francavilla.
Other Lifestyle Factors That Help Optimize Weight Loss
Patents not only lose fat on GLP-1s but also lose bone and muscle if they don't participate in strength training at least twice weekly. And as mentioned above, protein, calcium, and vitamin D are also very important for reducing the bone and muscle loss that can lead to frailty later in life.
The advisory also names other lifestyle factors like sleep, mental stress, substance use, and social connections as important priorities that can help patients maximize long-term success on these medications.
'GLP-1s help more than all the prior generations of obesity drugs, but that doesn't obviate the need for good physical activity and managing all the other stressors in one's life,' said Ziyad Al-Aly, MD, an assistant professor in the Division of General Medicine & Geriatrics at Washington University School of Medicine in St. Louis.
Ziyad Al-Aly, MD
Sleep is especially important and can often be overlooked. A wide breadth of research shows that sleep deprivation plays a role in weight loss. A study published in the April 2022 issue of the journal Nutrients found that individuals who slept for 5.5 hours per night lost less fat than those who slept for 8.5 hours per night.
Al-Aly noted that one of the lesser known side effects of these medications is that they can cause sleep disturbance. This means that sleep hygiene, for example, going to bed at the same time nightly, avoiding screen time before bed, and avoiding caffeine later in the day are particularly important for those taking these medications.
Substance use can also be problematic because while some research has shown that these medications impact the brain reward center, thereby reducing addictive behavior like alcohol abuse, patients who still drink too much are at a much greater risk for dangerous nutrient deficiencies. Physicians need to ensure that their patients are aware of these risks.
This advisory is tremendously helpful for physicians in providing a unified message, said Al-Aly. 'This is exactly what prescribers and doctors in patient communities really need, not only to help patients reach dramatic weight loss but to take into account their long-term risk factors and health.'