Q&A: Creating an ideal eating plan when using GLP-1s for weight loss
Key takeaways:
- GLP-1 receptor agonists can help women with obesity lose weight and improve health.
- A registered dietitian nutritionist can design a healthy eating plan before starting an obesity medication to maximize success.
Susan Weiner, MS, RDN, CDN, CDCES, FADCES, talks with Linda Gigliotti, MS, RDN, CDCES, FAND, about combining the use of GLP-1 receptor agonists with a healthy eating and lifestyle plan for successful weight loss.
Weiner: Why consider using a medication to lose weight?
Gigliotti: It’s not just about weight, or the number on the scale, anymore. Obesity is now recognized as a chronic disease and should be treated like other chronic conditions, such as diabetes or hypertension. Lifestyle interventions, including guidance on food choices, physical activity, sleep hygiene, stress management and goal setting, can result in about 5% to 10% weight loss, which is not enough for some people to manage their obesity and related chronic diseases. Effective management of obesity requires long-term, comprehensive care. Obesity medications and/or bariatric surgery are other options in the armamentarium to consider.
Weiner:How do these medications work?
Gigliotti: Incretin hormones are important regulators of metabolism. GLP-1 receptor agonists and glucose-dependent insulinotropic polypeptides (GIP) are gut-derived incretin hormones that mediate glucose-dependent insulin secretion and significantly impact glucose, lipids levels and body weight. GLP-1 aids in the loss of adipose tissue by binding to receptors in the pancreas, heart and brain, slowing gastric emptying, reducing appetite and decreasing postprandial glucose levels. Likewise, GIP increases insulin production, inhibits glucagon release and improves insulin sensitivity. The receptor agonists — synthetic forms of the hormones — are designed to impede the breakdown of the hormones, extending their impact, reducing energy intake by slowing gastric emptying and enhancing satiety signaling. The medications exert actions on other systems or organs of the body, including the pancreas, cardiovascular system and central nervous system. They are believed to cross the blood-brain barrier, regulating reward-seeking behavior and appetite. People also report a lessening of “food noise,” so they experience fewer cravings and temptations to eat.
Weiner: How do these medications work with lifestyle changes such as nutritional intake and physical activity?
Gigliotti: A prescription for an obesity medication is not a comprehensive obesity care plan. The need for lifestyle interventions does not go away. However, for people prescribed a GLP-1 receptor agonists, some refocus is needed. The medications decrease appetite so one eats less. Thus, what one consumes needs to be “nutrient-dense” to ensure a healthy eating plan. People are often more open to making healthier lifestyle choices because they are not distracted by “food noise,” so this can be an ideal time to work on food choices and patterns for long-term health management. Also, although the medications trigger people to eat less, they do not trigger people to move more. Including increased physical activity in any lifestyle counseling is important, too.
Weiner: Will the registered dietitian nutritionist (RDN) prescribe a diet plan to follow when taking obesity medications like a GLP-1?
Gigliotti: The focus shifts when taking incretin-based medications. It is true that to lose weight, one needs to consume fewer calories than the body is using, so historically a “diet plan” has been outlined for strategies to take in fewer calories. However, these medications reduce hunger and allow a person to feel full on fewer calories. Most people respond by decreasing their food intake because they are not hungry. There is less focus on the number of calories; managing the quality of calories is more important. The RDN can help to focus on the foods that are being consumed to make sure nutrient needs are being met.
There are a number of healthy eating patterns that one might choose to follow, such as Mediterranean, DASH, flexitarian or plant based. It is important to start with the individual and consider their preferences, cultural background, lifestyle and socioeconomic level. Think of adapting food intake, shifting toward a health food pattern for the long term, not a “diet.”
Weiner: What nutrients should specifically be addressed for women using these medications?
Gigliotti: Protein intake is important for anyone taking incretin-based therapies. Minimally, the recommended dietary allowance of 0.8 g/kg body weight should be consumed; however, there are recommendations for up to 1.2 g/kg to 1.5 g/kg. It is easier to think of this as an absolute minimum of 60 g to 90 g of protein daily, ideally divided into three meals during the course of a day. That is the equivalent of 4 to 5 ounces of lean meat three times daily.
There are no specific guidelines for carbohydrate and fat. However, because the medications delay gastric emptying and slow the gastrointestinal tract, a low-fat food plan is better tolerated.
The nutrients of specific consideration for women would be calcium and vitamin D for bone health. Milk, yogurt and calcium-fortified foods like orange juice are excellent sources of calcium. However, many women are already challenged to consume the recommended dietary allowance of 1,000 mg to 1,200 mg daily and may be even more challenged with a decrease in appetite from the medications. A calcium supplement with vitamin D is often warranted.
Weiner: If a woman is eating less, how do they make sure to get enough protein, vitamins, minerals and fiber?
Gigliotti: That is a major consideration for some people. Nutrient-dense foods become ultra-important. Every bite counts and should provide essential nutrients. Think of protein first, followed by vegetables and fruits, and then dairy and whole grain carbohydrates. This may be a time when people choose to use prepared foods or meal delivery services to ease the task of food preparation when the person just doesn’t feel like eating.
GLP-1 receptor agonists can also trigger adverse effects, including nausea, vomiting, diarrhea and constipation for about 30% of users. The good news is that the side effects are transient but then tend to subside. I strongly recommend staying hydrated and increasing fiber when using these medications. Drink a minimum of 64 oz (2 quarts) of water or other noncaloric fluid daily. A high-fiber diet emphasizes legumes, whole grains, vegetables and fruits. A fiber supplement, along with plenty of water, may be suggested if the person reports being too full and unable to consume high-fiber foods.
Weiner: Could these medications for weight loss impact lean body mass or bone health for women?
Gigliotti: The goal of intentional weight loss is to reduce excess adipose tissue because that is what contributes to health risks. However, it should be noted that even weight loss with lifestyle interventions also decreases lean body mass by about 15% to 25%. Simply stated, because the body is lighter, it no longer needs as much muscle to carry it around. Concern has been raised about the possibility of greater loss of lean body mass with the use of incretin-based therapies. However, research has been inconsistent measuring changes in body composition. Similarly, there is evidence suggesting that weight loss, especially rapid weight loss, can result in the reduced bone quantity and lower bone mineral density. Women need to be aware of these impacts when considering obesity medications because women tend to have less muscle mass and are at greater risk for osteopenia and osteoporosis than men.
Weiner: When should a person using obesity medications see an RDN?
Gigliotti: It’s never too early to see an RDN. The RDN who specializes in obesity care can be the ideal person to talk with before seeking a prescription for an obesity medication. It is helpful to explore if medications are an appropriate option for the individual and what their goals and expectations are. It is also important to understand how medications induce weight loss, the potential adverse effects and how to manage them. The RDN can also assess and evaluate the client’s knowledge and technique used to administer the subcutaneous incretin-based therapies.
The success of weight loss and decrease in food noise when taking the medications makes it an ideal time to work with people on lifestyle choices for long-term weight and health management. The RDN can help clients manage their expectations of the anticipated impact of an incretin-based therapy on their weight and other outcomes by working with them on realistic goals and personalizing recommendations to the individual.
Weiner: Do these medications need to be taken for life?
Gigliotti: Despite what social media sometimes implies, these medications are not quick fixes for excess weight. Chronic diseases require long-term management. They are one tool that can be used to treat the chronic disease of obesity. In addition to obesity and type 2 diabetes, GLP-1s have indications to reduce risk for cardiovascular disease, sleep apnea and kidney disease.
Studies show that when these obesity medications are stopped, weight is regained. How the medications could be used over the long term is still being studied and will likely vary with the individual. Some people may stay on a medication, possibly at a lower dose, long term. Others may master lifestyle changes with food, physical activity, sleep and stress management, so they can taper off the medication and manage their health long term with lifestyle changes. Others may work with their health care professional to use obesity medications intermittently along with lifestyle modifications to manage their health. There are additional medications in development that may provide other options. This is an exciting time to see progress in the treatment and management of this chronic health concern.
For more information:
Linda Gigliotti, MS, RDN, CDCES, FAND, is a consultant in private practice and former program director of the University of California Irvine Weight Management Program. She can be reached at lmgigliotti@gmail.com or on LinkedIn here.
Susan Weiner, MS, RDN, CDN, CDCES, FADCES, is the owner of Susan Weiner Nutrition PLLC and the Healio | Women’s Health & OB/GYN Nourish to Flourish column editor. She can be reached at susan@susanweinernutrition.com; X (Twitter): @susangweiner.