Nutritional deficiencies associated with anti-obesity pharmacotherapy

Abstract

Obesity is a chronic, multifactorial disease associated with substantial morbidity, mortality, and healthcare burden worldwide. The increasing prevalence of obesity has led to expanded use of anti-obesity pharmacotherapy as an adjunct to lifestyle modification for achieving sustained weight reduction and improving obesity-related comorbidities. Recent advances in pharmacological treatment, particularly with glucagon-like peptide-1 (GLP-1) receptor agonists and dual glucose-dependent insulinotropic polypeptide GLP-1 receptor agonists, have significantly improved weight-loss outcomes compared with earlier therapies. Despite these therapeutic benefits, growing evidence suggests that anti-obesity medications may influence nutritional status through mechanisms including reduced energy intake, appetite suppression, delayed gastric emptying, gastrointestinal adverse effects, and impaired nutrient absorption. These physiological changes may increase the risk of deficiencies involving both macronutrients and micronutrients, particularly during prolonged treatment or rapid weight loss. Orlistat has been consistently associated with reduced absorption of fat-soluble vitamins due to inhibition of intestinal fat absorption, whereas appetite-suppressing agents may contribute to inadequate intake of protein, iron, calcium, vitamin B12, folate, zinc, magnesium, and other essential nutrients by limiting overall food consumption. Individuals with obesity often present with pre-existing nutritional inadequacies, making them more susceptible to clinically significant deficiencies during pharmacological therapy. Preservation of lean body mass, maintenance of adequate protein intake, and ensuring sufficient dietary quality have become increasingly important considerations in modern obesity management. Nutritional assessment should therefore extend beyond body weight to include dietary evaluation, body composition, biochemical monitoring when indicated, and individualized nutrition support. Clinical management requires recognition of the distinct nutritional profiles associated with different classes of anti-obesity medications to facilitate appropriate dietary counseling, targeted supplementation, and regular follow-up. Integrating pharmacological therapy with comprehensive nutritional care may enhance treatment effectiveness while reducing the likelihood of adverse nutritional consequences. As the use of highly effective anti-obesity medications continues to expand, greater emphasis on nutritional monitoring and individualized patient management will be essential for maximizing long-term health outcomes and ensuring safe, sustainable weight management.