Comparing Diet and Drug Approaches to Obesity: How GLP-1 Drugs Stack Up Against Mediterranean and Keto Diets Long-Term | Research

The takeaway

Liraglutide and naltrexone/bupropion produce significant weight loss but face long-term adherence challenges, while the Mediterranean diet offers more sustainable but moderate benefits for obesity management.

Long-term sustainability varies
Pharmacological options like liraglutide show significant weight loss but adherence challenges, while the Mediterranean diet provides moderate but more sustainable outcomes

What the researchers found

This review compares long-term obesity management strategies including the Mediterranean diet (MedDiet), very low-energy ketogenic therapy (VLEKT), naltrexone/bupropion, and the GLP-1 receptor agonist peptide liraglutide. The MedDiet offers sustainable cardiovascular benefits with moderate weight loss. VLEKT produces rapid weight loss but has sustainability concerns. Both liraglutide and naltrexone/bupropion promote significant weight loss and improve metabolic markers, but long-term adherence and side effects remain open questions for both pharmacological approaches.

Why it matters

Obesity is a chronic disease requiring sustained treatment. This review places GLP-1 receptor agonists like liraglutide alongside dietary interventions in a comparative framework, highlighting that while peptide drugs produce significant short-term weight loss, the Mediterranean diet may be more sustainable long-term. Understanding how to combine these approaches optimally is critical for lasting obesity management.

How the study worked

Narrative review examining published evidence on long-term efficacy and safety of four obesity management strategies: Mediterranean diet, very low-energy ketogenic therapy, naltrexone/bupropion, and liraglutide. The review evaluates weight loss outcomes, metabolic improvements, cardiovascular benefits, adherence, and safety profiles.

Who was studied

Review article covering adults with obesity across multiple treatment modalities

What this study cannot tell us

This is a narrative review, not a systematic review or meta-analysis. It focuses on liraglutide rather than newer GLP-1 RAs like semaglutide or tirzepatide, which have shown greater weight loss efficacy. Direct head-to-head comparisons between dietary and pharmacological strategies are limited in the literature. The review acknowledges that long-term data beyond 1-2 years remain sparse for most interventions.

How to read the evidence

This is a moderate-grade narrative review synthesizing evidence from clinical trials and observational studies of multiple obesity interventions. The comparative analysis is informative but lacks the rigor of a systematic review or meta-analysis.

When this study was published

Published in 2025, this review is current but focuses on liraglutide rather than the newer, more potent GLP-1 RAs (semaglutide, tirzepatide) that are now more commonly prescribed.

The bigger picture

As GLP-1 receptor agonists dominate the obesity treatment landscape, this review provides important perspective: drugs alone may not be sufficient for long-term weight management. The field is increasingly recognizing that combining pharmacological tools (like GLP-1 RAs) with sustainable dietary patterns (like the Mediterranean diet) may offer the best outcomes. This integrated approach reflects the chronic disease model of obesity management.

Questions still open

Would newer GLP-1 RAs like semaglutide or tirzepatide change the long-term efficacy comparison, given their greater weight loss potential?
What is the optimal way to combine Mediterranean diet principles with GLP-1 RA treatment for sustained weight management?
How do the long-term side effect profiles of GLP-1 RAs compare to the health risks of sustained ketogenic diets?

Common questions

Is taking a GLP-1 drug like liraglutide better than dieting for weight loss?

In the short to medium term, liraglutide produces greater weight loss than most dietary approaches. However, this review notes that long-term adherence to medication can be challenging, and the Mediterranean diet offers more sustainable benefits including cardiovascular protection. Many experts now recommend combining dietary changes with pharmacological treatment for the best long-term outcomes.

What happens when you stop taking GLP-1 drugs for weight loss?

This review highlights that long-term adherence and weight maintenance after stopping treatment are key challenges for pharmacological obesity treatments. Evidence suggests most people regain significant weight after discontinuing GLP-1 RAs, which is why sustainable lifestyle approaches like the Mediterranean diet are considered important complements to drug therapy.

Read the original research

Long-Term Efficacy and Safety of Nutritional and Pharmacological Strategies for Obesity.

Current obesity reports, 14(1), 1

View on PubMed ↗Publisher’s paper ↗

Citation

Barrea, Luigi; Boschetti, Mara; Gangitano, Elena; Guglielmi, Valeria; Verde, Ludovica; Muscogiuri, Giovanna. (2025). Long-Term Efficacy and Safety of Nutritional and Pharmacological Strategies for Obesity.. Current obesity reports, 14(1), 1. https://doi.org/10.1007/s13679-024-00602-y