Co-written with Jenna Moore, RD, CSSD

As a psychiatrist, I've seen the mental health benefits that go along with successful weight loss—improved mood, enhanced self-esteem, and reduced anxiety. And as a registered dietitian, Jenna Moore has witnessed the physical benefits firsthand. Medicines such as semaglutide and tirzepatide have produced a breakthrough in the treatment of obesity. Patients generally lose 15-20% of their body weight. These medicines mimic the effects of a natural hormone called glucagon-like peptide-1(GLP-1) and are known as “GLP-1 agonists.” However, both of us have become increasingly concerned about a silent crisis that is developing behind these success stories: Malnutrition.

GLP-1 agonists work by causing us to feel full, delaying the release of food from our stomachs, and reducing our appetite. While this can produce impressive weight loss, it also creates a nutritional paradox. Recent studies have found that individuals using GLP-1 agonists reduce their caloric intake by 16-39%. This can result in some individuals consuming such a small number of calories that they are at risk of developing micronutrient insufficiency.

From my psychiatric practice, I can tell you that caloric restriction doesn't just affect your body—it also impacts your mental health. Some patients experience brain fog, difficulty concentrating, and trouble sleeping. What many people don't realize is that these aren't necessarily side effects of the GLP-1 agonists. They may be symptoms of a nutritional deficiency.

From my dietitian's perspective, the food choices people make on these medications often worsen the problem. When their appetite is severely suppressed, people tend to eat whatever sounds tolerable rather than what's nutritionally optimal. This can lead to

© Psychology Today