Bariatric surgery leads to impressive weight loss, often exceeding that expected by the reduction in food intake alone. The mechanisms responsible for this excess weight loss are not fully understood, but several factors contribute to the weight loss observed after bariatric surgery.
Physiological Factors
One key factor is the alteration of gut hormones, such as ghrelin, peptide YY, glucagon-like peptide-1 (GLP-1), and cholecystokinin, which play important roles in regulating hunger, satiety, and energy balance. Bariatric procedures, such as Roux-en-Y gastric bypass and sleeve gastrectomy, can significantly modify the secretion of these hormones, leading to reduced hunger and improved satiety.
Altered Gut-Brain Signaling
Furthermore, bariatric surgery can also alter the gut-brain signaling pathways, which can influence food intake, appetite, and energy regulation. The changes in gut hormone secretion and gut-brain communication contribute to the sustained weight loss observed after these procedures.
Metabolic Adaptations
Another important factor is the metabolic adaptations that occur after bariatric surgery. These procedures can lead to increased resting energy expenditure, improved insulin sensitivity, and altered fat and glucose metabolism. These metabolic changes can further potentiate the weight loss observed after surgery.
Gut Microbiome Alterations
Emerging evidence also suggests that bariatric surgery can induce changes in the gut microbiome, which may play a role in the weight loss and metabolic improvements seen after these procedures. The altered gut microbial composition can influence various physiological processes, including energy regulation, inflammation, and metabolic homeostasis.
Overall, the impressive weight loss observed after bariatric surgery is the result of a complex interplay of physiological, metabolic, and gut-related factors, which collectively contribute to the sustained and substantial weight loss experienced by patients.