Genetic Influences on Weight-Loss Drug Effectiveness Revealed
A registered dietitian has detailed the scientific reasons why popular weight-loss medications, including Wegovy and Mounjaro, might fail to produce rapid or significant results for certain individuals. These injections, classified as GLP-1 receptor agonists, are currently used by an estimated 2.4 million people across the United Kingdom. They function by imitating the natural hormone that controls blood sugar levels, appetite, and digestive processes.
Study Highlights Genetic Resistance to GLP-1 Treatments
Recent research conducted by scientists at Stanford Medicine indicates that approximately one in ten people may experience reduced effectiveness from these so-called miracle drugs due to specific genetic variants. This condition, referred to as GLP-1 resistance, involves genetic traits that cause elevated but less biologically effective levels of the GLP-1 hormone. Consequently, individuals with these variants require higher amounts of GLP-1 to achieve the same physiological impact, potentially diminishing the weight-loss benefits of the medications.
Ro Huntriss, a dietitian who works extensively with patients on GLP-1 therapies, emphasised that weight loss outcomes exist on a broad spectrum. While most users lose between 10 and 20 percent of their body weight, some may only achieve a 5 percent reduction. Genetic influences can significantly alter how the body responds to these drugs, creating variability in results that is not always communicated to patients.
Research Focus on PAM Enzyme Variants
The study, published in the journal Genome Medicine, concentrated on a genetic variant affecting the PAM enzyme, which activates GLP-1. This variant is more prevalent among individuals with diabetes. Contrary to expectations, researchers discovered that people with the PAM variant had higher GLP-1 levels but slower reductions in blood sugar, highlighting a complex biological interaction.
Ms Huntriss commented, "Although the science is in its infancy, this research supports the idea that, in some cases, variability in response may be influenced by biological factors beyond adherence or effort." She cautioned, however, that it is too early to recommend genetic testing to predict success on GLP-1 medications, as the understanding of these mechanisms remains preliminary.
Multifactorial Nature of Weight-Loss Success
The dietitian noted that GLP-1 resistance is merely one component of a larger puzzle. Factors such as insulin resistance, variations in dopamine and reward sensitivity, dietary habits, lifestyle choices, and medication management all contribute to how effectively these drugs promote weight loss. Relying solely on GLP-1 injections is often insufficient; adopting a diet rich in protein and fibre while maintaining a lower calorie intake is crucial for optimal results.
"Our dietary habits still need to change, our calorie intake needs to be significantly lower than what it was, to lose weight," Ms Huntriss explained. "Eating the right diet can actually drastically reduce the side effects, which then means adherence is greater, which then means the weight loss is better."
Personalised Approaches to Treatment
While GLP-1 medications are effective for the majority of users, they may not be suitable for everyone. Ms Huntriss advised that patients and practitioners should collaboratively assess whether the treatment is working. If desired outcomes are not met despite behavioural and medication adjustments, alternative approaches might be necessary. This underscores the importance of personalised healthcare in weight management, moving beyond a one-size-fits-all solution.
The findings highlight the need for greater awareness and communication about the potential limitations of weight-loss drugs, ensuring that patients have realistic expectations and can explore comprehensive strategies for health improvement.
