Weight loss drugs may risk nutritional deficiencies without adequate professional guidance: Study

GLP-1 drugs like semaglutide and tirzepatide mimic natural fullness hormones, slashing calorie intake by 16-39% and transforming obesity treatment. In the UK alone, 1.5 million people now use them, with 95% buying privately where nutritional counseling often doesn't exist. NICE guidelines require diet and exercise alongside NHS prescriptions, but private users frequently go unsupported, leaving appetite suppression to do all the work.

The research team systematically reviewed available studies on nutrition during GLP-1 treatment, focusing on calorie intake, body composition changes, protein adequacy, and patient experiences. They identified just 12 relevant studies on semaglutide and tirzepatide, but found them inconsistent—lacking standardized protocols for dietary assessment or intervention. This made it impossible to draw firm conclusions about optimal support strategies.

Critical findings emerged despite the evidence gaps. Lean body mass, including vital muscle tissue, comprised up to 40% of total weight lost during treatment. Reduced food intake often compromised protein, fiber, vitamins, and minerals, risking fatigue, weakened immunity, hair loss, osteoporosis, and falls from muscle wasting. Some observational data even showed users consuming excessive saturated fats, suggesting the need for personalized fat guidance alongside national recommendations.

Researchers recommend borrowing proven strategies from bariatric surgery protocols: prioritizing nutrient-dense foods with high-quality protein spread evenly across meals to preserve muscle during rapid weight loss. Small, frequent meals may reduce nausea and improve tolerability. While awaiting more robust trials, they launched AMPLIFY—a study capturing real-world experiences from diverse GLP-1 users, including underrepresented communities, to shape practical support systems.

The message is clear: these drugs demand nutritional partners, not solo performance. Without integrated care, weight loss victories risk becoming nutritional defeats.

REFERENCE: Spreckley, M., et al. (2026). Nutrition Strategies for Next‐Generation Incretin Therapies: A Systematic Scoping Review of the Current Evidence. Obesity Reviews. DOI: 10.1111/obr.70079. https://onlinelibrary.wiley.com/doi/10.1111/obr.70079.