Nutritional Health While Taking a GLP - 1

Nutrition and lifestyle factors heavily impact the efficacy, tolerability, and continued use of GLP 1 treatments. Because of the highly varied results among individuals taking these medications, it is crucial to understand the factors associated with better outcomes long term. This blog focuses on a brief summary of nutritional recommendations to consider. 

The most common pitfalls while on treatment with GLP 1 include side effects, varied weight loss results, high discontinuation rates, nutrient deficiencies, loss of lean body mass, and weight recurrence. All of these are highly affected by lifestyle factors. Let’s take a closer look and see what to watch for to have the best results. While the most common side effects are gastrointestinal, there are others including fatigue, neurological side effects, hair loss and skin changes. Gastrointestinal side effects are most commonly affected by medication dosing, diet, including what is eaten, how much, and the timing of eating.

Medication Dosing

For medication dosing, the study protocol dictated increasing the dose every 4 weeks until reaching the target dose. In clinical practice, individualizing the dosing and timing of dose escalation can improve outcomes and reduce side effects. If the dose is not escalated soon enough, discontinuation is more likely as it appears the treatment is not working. Probably because about half of people are paying out of pocket for these medications, lower weight loss is associated with higher rates of discontinuation. On the other hand, increasing the dosage too fast can result in significant side effects, not uncommonly resulting in emergency department or urgent care visits, acute kidney injury, interruption of work or leisure activities, and the need to temporarily stop the treatment, at times needing to restart at the lowest or lower dosage. Strategies can include using the lowest effective medication strength, or remaining on a strength for longer than four weeks. There are reports of “off label” dosing widely read by patients on the internet, often called “microdosing” that include strategies such as taking dosages not FDA approved or splitting doses by taking a half volume twice weekly. The safety and efficacy of these dosing regimens has not been established. It is often seen that ondansetron is taken to manage nausea, but this can worsen constipation. Recently, it seems the medications metoclopramide or prochlorperazine are being considered instead, but these can cause tardive dyskinesia (involuntary movements) which can be permanent, even when the medication is discontinued. It is important that patients are counseled on the risk before being prescribed these medications for temporary symptom relief.

Nutrient deficiencies

Appetite reduction is the hallmark of treatment with GLP 1 medications. Reduction in calorie intake can be as much as 18-36%. Some people report an actual food aversion, making eating challenging. Nutrient deficiencies can be present before treatment for various reasons in individuals with obesity, including prior bariatric surgery, prior diets that called for the restriction of calories or certain food groups, ingestion of highly processed foods, altered gut microbiome, or associated medical conditions such as celiac disease. On treatment, calorie intake under 1200 per day in women or 1800 in men is associated with higher risk of nutrient deficiencies. This can increase the risk of side effects such as hair loss, skin changes, fatigue, or muscle or bone loss. 

Nutrient Timing

Eating small, frequent meals can be better tolerated than typical sized meals of solid foods when there is significant appetite reduction. This strategy can also reduce side effects such as nausea, diarrhea, or belching. 

Food Selection

Soft or liquid foods may be better tolerated when there is low appetite and delayed stomach emptying. Foods that are dense in nutrition is crucial because of the overall drastic decrease in the amount of nutrition consumed. Nutrient dense foods to encourage include fruits, vegetables, whole grains, legumes, lean proteins, nuts and seeds. Foods to avoid include added sugars, refined carbohydrates such as white flour and white rice. A multivitamin and vitamin D can be considered to avoid common nutrient deficiencies. 

Protein Intake

Protein intake recommendations are a common source of confusion due to the presence of multiple reasons for varying recommendations. The most common sources of varied recommendations are whether to use current weight or ideal weight for calculations, how to adjust them for activity level and goals of either weight loss or muscle building, and simple disagreement on what the ideal protein intake is. For example, the general recommendation for protein intake is 0.8 grams per kilogram per day. However, higher targets such as 1.2 to 1.6 grams per kilogram per day during active weight loss have been suggested, which is up to double the general recommendation. Adding in the source of variation of what body weight to use amplifies the variation in recommendations. Oftentimes, people are reporting significant difficulty in meeting protein requirements, at times leading to increased side effects when attempting to reach those targets, as well as disappointment with the amount of weight loss achieved, which we know can lead to higher rates of discontinuation. Additionally, people may be consuming processed meats or higher saturated fats to reach these goals, or have high ingestion or protein shakes which can exacerbate constipation, bloating, or food expense. Two strategies have been proposed to help provide guidance on protein intake while on GLP 1 treatment: (1) use 1.5 grams per kilogram of lean body mass (fat free mass), or (2) use a range of 80-120 grams per day for all persons. The former may be more individualized but require body composition analysis, while the latter is more easily applied and can be individualized based on things such as height, gender, and apparent muscularity. 

Medical Foods while on GLP 1s

The Rainier Medical meal replacements and medical foods were designed to provide complete nutrition supplemented with micronutrients. They have been used for individuals who have had bariatric surgery which has many of the same effects on appetite and food tolerance as the GLP 1 medications. Appropriate use of medical grade meal replacements and nutritional supplements designed for individuals on a low calorie diet with reduced gastric capacity and prone to GI side effects may enhance tolerability and outcomes and reduce side effects, nutritional deficiencies, and the loss of lean body mass. These should be used with medical supervision, as GLP 1s are intended. These products are mentioned specifically because of eleven years of observational experience of patient use while monitored with blood work, body composition analysis and tolerability. It is not intended to imply they are the only or best option.

Overall, nutrition factors are crucial to consider when individualizing treatment outcomes while on a GLP 1, in combination with medication dosing.

These factors also vary within the individual over time as one progresses from weight loss to weight maintenance, as the appetite suppression tends to decrease over time, as aging progresses and activity levels change, as well as psychosocial and other factors evolve. All of this portrays the use of GLP 1 medications as a dynamic treatment that requires frequent reassessment and optimization while monitoring things such as other medications, body composition, appetite, sense of well being, blood work, and more. Be sure to use these powerful tools under medical supervision with a licensed medical provider incorporating the totality of your medical and health information while guiding and supporting you in a patient-centered approach. 

Reach New Peaks on a GLP 1,

Valerie Hope-Slocum Sutherland, MD

Artificial Intelligence was not used to generate this article.

Reference:

https://pmc.ncbi.nlm.nih.gov/articles/PMC12304835/

Mozaffarian D, Agarwal M, Aggarwal M, Alexander L, Apovian CM, Bindlish S, Bonnet J, Butsch WS, Christensen S, Gianos E, Gulati M, Gupta A, Horn D, Kane RM, Saluja J, Sannidhi D, Stanford FC, Callahan EA. Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity (Silver Spring). 2025 Aug;33(8):1475-1503. doi: 10.1002/oby.24336. Epub 2025 May 30. PMID: 40445127; PMCID: PMC12304835.

Dr. Sutherland, February 2026