Paradox between bariatric (RYGB) surgery and pharmacological interventions for obesity
| RYGB surgery | Pharmacological interventions | |
|---|---|---|
| Body weight loss | Up to 33% | Up to 10% |
| Body weight loss maintenance | Sustained loss of up to 18% of BW over 15 years | Poorly sustained over 2 years |
| Rate of weight loss | Rapid within first year | Slow—steady |
| Reduce cardiovascular mortality | Yes | Unproven to date; studies ongoing |
| Insulin resistance | Improvement to resolution of insulin resistance | No effect |
| Dyslipidaemia | Mild improvement | No change |
| Hypertension | Significant improvement | Mild improvement |
| Mechanism of action | ||
| Hypothalamus | Questionable effect | L: Increase POMC pathway via 5HT2c receptor P-T: noradrenergic—dopaminergic pathways; unclear mechanism |
| Brainstem | Unclear | No effect |
| Vagus nerve | Cuts gastric branches of vagus nerve | No effect |
| GI hormones | Increase GLP-1, PP, PYY, OXM (especially early postprandially) | No effect |
| Effective gastric reservoir size | Decreased | No effect |
| Side effects | Mainly surgery related nutrients deficiency | Lorcaserin and Topiramate-Phentermine (ER) may have CNS side effects |
CNS, central nervous system; L, Lorcaserin; OXM, oxyntomodulin; POMC, pro-opiomelanocortin; P-T, Phentermine-Topiramate Extended Release (ER); PYY, Peptide tyrosine–tyrosine; RYGB, Roux-en-Y gastric bypass.