Table 1 Nutritional Considerations with GLP-1 RA Therapy vs Bariatric Surgery.
Nutritional Parameter | Bariatric Surgery Mechanisms | GLP-1 RA Mechanisms | Bariatric-Based Nutritional Strategies |
|---|---|---|---|
Lean Mass Loss and Sarcopenia | Malabsorption and energy restriction accelerate lean mass loss | Energy deficit and reduced protein intake contribute to lean mass loss | Higher protein intake from high-quality sources; early prioritisation of protein; monitoring for sarcopenia, especially in older adults and those at risk of or with sarcopenic obesity. Between 0.8–1.6 g/kg/d or absolute protein amounts (80–120 g/day) |
Micronutrient Deficiency | Reduced absorption of iron, B12, vitamin D, calcium, thiamine | Reduced intake and possible dietary quality due to early satiety, nausea, and food restrictions | Pre-treatment micronutrient screening; routine lifelong complete multivitamin and mineral supplementation (including iron, B12, calcium, zinc, copper and folic acid); proactive monitoring for deficiencies every 6 months |
Altered Food Preferences | Changes in taste, aversions to meats and fats | Decreased interest in nutrient-dense foods, especially protein- and fat-rich foods | Behavioural nutrition therapy to address food-related cognition, sensory experience, and emotional eating; patient education on food choices and preferences; referral to psychological support, if required. |
Gastrointestinal Symptoms | Nausea, vomiting, early satiety, diarrhoea, dumping syndrome | Nausea, vomiting, constipation, particularly during dose titration and higher doses | Small, frequent meals; slow eating; fluid separation from meals; bland, low-fat foods during nausea; consider food containing ginger; increase fibre and fluid intake; consider use of medication if required. |
Gallstone Formation | Rapid weight loss increases risk of gallstones due to gallbladder stasis and cholesterol supersaturation | Similar rapid weight loss trajectories; gallstones may form due to similar mechanisms | Moderate fat intake; ensure adequate hydration and fibre intake; consider ursodeoxycholic acid prophylaxis in high-risk cases, particularly for rapid treatment responders |
Nutritional Monitoring | Regular biochemical surveillance and dietitian-led follow- up; routine screening for deficiencies and adjustments | No routine nutritional monitoring in clinical practice, leading to potential undiagnosed deficiencies | Implement structured nutritional follow-up with regular biochemical testing (e.g., B12, iron, calcium); integrate dietetic support into clinical pathways, especially for long-term therapy |
