Dr. David A. Kessler, a prominent figure in public health and former Commissioner of the Food and Drug Administration (FDA), has spent his career focused on keeping people healthy. Yet, by his own admission, applying that focus to himself wasn’t always easy, particularly when it came to managing his weight.
Like many, Kessler struggled with food choices in a demanding environment, gaining weight at different points in his life, including after an intense period working on the White House COVID-19 Response Team. When traditional diet and exercise methods didn’t yield the results they once had, an endocrinologist suggested he try a glucagon-like peptide-1 (GLP-1) drug, a class of medications that includes popular names like Wegovy and Mounjaro.
Kessler’s personal experience using GLP-1s, coupled with his extensive background in public health and the science of food and obesity, forms the basis of his new book, Diet, Drugs, and Dopamine: The New Science of Achieving a Healthy Weight. He shares key insights from his journey and research, highlighting both the remarkable effectiveness of these drugs and the realities of using them.
Our Food Environment’s Impact on Weight
Kessler argues that the modern food environment plays a powerful role in driving weight gain. We are surrounded by highly palatable, energy-dense foods—what he terms “ultra-formulated”—engineered to trigger our brain’s reward system. This isn’t simply a matter of willpower; it’s a biological response conditioned by constant availability and marketing. He colorfully describes it as living in a “food carnival,” asking, “What did we expect to happen?”
He sees GLP-1 drugs as a crucial tool in navigating this challenging environment. While the ideal scenario would be changing the food landscape itself, Kessler isn’t optimistic that will happen quickly. In the meantime, these medications offer a powerful way to counteract the biological drives stimulated by ultra-formulated foods.
Beyond BMI: Focusing on Visceral Fat
Kessler joins a growing number of experts who question the sole reliance on Body Mass Index (BMI) as the primary indicator of health. Instead, he emphasizes the significance of visceral fat—the fat stored deep within the abdominal cavity surrounding organs. Visceral fat is metabolically active, releasing inflammatory substances linked to a host of serious health issues, including heart disease, diabetes, kidney disease, certain cancers, and potentially neurodegenerative changes.
While body composition scans offer precise measurements, Kessler notes that waist circumference can provide a rough estimate of risky visceral fat levels (over 40 inches for men, 35 inches for women).
The Reality of Taking GLP-1 Medications
GLP-1 drugs are potent appetite suppressants. They work by mimicking natural hormones that signal fullness and by slowing down gastric emptying, meaning food stays in your stomach longer. This mechanism can significantly reduce the amount of food needed to feel satisfied.
However, Kessler is candid about a common side effect: feeling uncomfortable. He describes it as being “at the edge of nausea.” While some people experience minimal issues, for many, pushing past this feeling by continuing to eat can lead to significant gastrointestinal distress, including pain, diarrhea, and vomiting. This discomfort, while unpleasant, serves as a powerful negative reinforcement, conditioning patients to eat less and avoid heavier foods.
Dr. Kessler’s experience aligns with research indicating that many individuals find staying on GLP-1 drugs challenging. Studies suggest a significant percentage of patients discontinue the medication within a year, often citing side effects as a primary reason. Even other physicians who have used these drugs personally have reported severe side effects that led them to stop taking them. Given the potential for severe side effects, including those requiring emergency care, Kessler stresses that drugmakers and the FDA should provide clearer information to the public on how these drugs work and what to expect.
The Importance of Medical Guidance
Navigating GLP-1 treatment requires professional support. Kessler strongly advises working closely with a physician experienced in obesity medicine or at least a general internist or primary care doctor. He also highlights the value of partnering with a registered dietician or nutritionist to adapt eating habits effectively while on the medication. Such a team approach can help manage side effects, adjust dosing, and ensure the patient maintains proper nutrition.
Essential Dietary Practices While on GLP-1s
Even with the appetite suppression from GLP-1s, mindful food choices remain crucial. Kessler emphasizes two key dietary components:
- Protein: Eating plenty of protein is vital. It enhances satiety, helping you feel fuller for longer, and displaces less healthy options like excess carbohydrates and fats.
- Fiber: High-fiber foods are critically important. Because GLP-1s slow gastric emptying, ensuring adequate fiber intake helps keep things moving through the digestive tract. Kessler issues a stark warning that unchecked constipation can escalate to severe intestinal obstruction and potentially life-threatening complications. Staying well-hydrated is also essential.
Understanding Potential Risks
While effective, GLP-1 drugs come with risks. Kessler expresses concern that some patients may restrict calories too drastically, potentially leading to malnutrition (consuming as little as 600-800 calories per day) or triggering eating disorders.
Another significant risk is muscle loss. Studies indicate that a notable portion of the weight lost on GLP-1s can be lean body mass, including muscle. One study Kessler cites showed 40% of weight loss was lean mass, with about a third being muscle. Maintaining adequate nutrition and engaging in strength training is essential to mitigate this, particularly for older adults susceptible to muscle wasting.
Certain individuals should avoid GLP-1s entirely, including those with a personal or family history of specific thyroid/endocrine cancers, severe kidney disease, pancreatitis, inflammatory bowel diseases, uncontrolled severe constipation or diarrhea, gastroparesis, or those who are pregnant.
The Challenges of Access and Compounded Versions
The high cost and inconsistent insurance coverage for GLP-1s, particularly for weight loss alone, present major barriers for many. This has led some patients to seek lower-cost alternatives like compounded versions. Kessler, however, issues a strong caution against these. Unlike FDA-approved brand-name drugs which undergo stringent manufacturing standards and inspections, compounded versions may lack consistent quality control, traceability, and verification of active ingredients. Many patients face the difficult reality of losing access to these medications due to cost or insurance changes, prompting a search for various alternatives and strategies to manage weight regain.
The Uncharted Territory of Stopping GLP-1s
One of Kessler’s most significant critiques is the lack of guidance on discontinuing GLP-1 treatment. After achieving his weight-loss goal and experiencing some minor side effects, he decided to stop the medication. However, he found himself “flying blind” when it came to maintaining his lost weight.
There is currently limited data and formal guidance from drug companies or the FDA on how to safely taper off the drugs or manage the return of appetite and cravings that can occur after stopping. Kessler’s personal experience involved trial-and-error, which he argues is not how powerful medications should be used. He stresses the urgent need for pharmaceutical companies to conduct research and the FDA to establish clear guidelines for safe discontinuation and weight maintenance strategies post-treatment. A high-protein diet may offer some help post-GLP-1 by promoting satiety similar to the drug’s effect, but it’s not a guaranteed solution.
In conclusion, Dr. Kessler’s personal journey and expert insights reveal that GLP-1 drugs are transformative tools for weight loss in a challenging food environment. However, their use is complex, requiring careful management of potential side effects, diligent attention to nutrition (especially protein and fiber), awareness of risks, and robust medical supervision. Addressing the issues of access, cost, and clear guidance on long-term use and discontinuation remains critical for realizing the full potential of these medications in the ongoing effort to combat obesity and improve public health.
