The challenge of treating obesity: the endocannabinoid system as a potential target

Obesity and cardiometabolic risk, or the metabolic syndrome, continue to be major public health concerns. To date, treatment with lifestyle and pharmacotherapy interventions has resulted in limited efficacy in reversing the upward trend in this present-day health crisis. Research reveals that a modest 5% to 10% weight loss results in substantial improvement in health. While obtaining modest weight loss is often achievable, maintaining lost weight is challenging. Research has recently improved our understanding of several endogenous pathways that influence body weight regulation and disease risk. The endocannabinoid system has been found to regulate appetite and energy expenditure, as well as lipid and glucose metabolism. Interest in blocking stimulation of this pathway to aid weight loss and reduce cardiometabolic risk factor development is an area of interest and research. This article reviews the mechanisms by which the endocannabinoid system is believed to influence body weight regulation and cardiometabolic risk factors, as well as the results of clinical trials investigating the safety and efficacy of a selective cannabinoid-1 receptor antagonist (rimonabant). Clinical trials investigating rimonabant treatment resulted in substantial reductions in body weight and markers for cardiometabolic risk in study participants. However, increases in adverse events were reported in the drug-treated group. Data regarding long-term benefit and adverse events from rimonabant treatment are being collected in several ongoing clinical trials. Rimonabant is currently available in 42 countries, but has not received United States Food and Drug Administration approval. Food and nutrition professionals play a pivotal role in tackling the current obesity crisis; it is essential that they understand the many physiological mechanisms regulating body weight. Emerging research data reveals pathways that influence appetite and energy metabolism, and this knowledge may form the foundation for new clinical treatment options for obese individuals.