Research
Hormonal
Gastric bypass surgery reduces appetite and promotes long-term weight loss primarily through hormonal changes, specifically decreased ghrelin and increased PYY, rather than solely mechanical restriction.
Gastric bypass surgery works largely by changing your gut hormones: it lowers hunger signals (ghrelin) and boosts fullness signals (PYY). While surgery is a major step, you can try to mimic these hormonal effects through dietary choices that naturally stimulate these gut hormones, potentially helping with long-term weight management.
GoodQualifiesHIGH confidence
Interestingly, the success of bypass surgery may be as much hormonal as mechanical... ghrelin levels were 77% lower in the gastric bypass group compared with matched BMI controls... Reduced circulating ghrelin with a possible elevation of circulating PYY 3-36 could account for the paradoxical decrease in hunger reported by most patients, and explain the long-term weight loss usually seen following gastric bypass surgery.
Why this rating
Based on cited studies measuring plasma ghrelin and PYY levels in post-surgical patients.
Source
Appetite regulation: from the gut to the hypothalamus
Nicola M. Neary et al. · Clinical Endocrinology · 2003
DOI 10.1046/j.1365-2265.2003.01839.x
narrative_reviewCited 189×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Peripheral administration of PYY 3-36 significantly inhibits food intake in humans by acting on hypothalamic Y2 receptors to suppress orexigenic NPY neurons.Good
- Leptin treatment is effective for weight loss only in individuals with congenital leptin deficiency, but offers limited benefit for the vast majority of obese people who have high circulating leptin.Good
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →