Western Zone Obesity Network · Dietitian Reference
A dietitian-facing guide to pre- and post-operative nutrition follow-up and micronutrient management for sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB).
Introduction
This is a dietitian-facing reference for the nutritional care of patients before and after bariatric surgery in the Western Zone. It covers the pre-operative assessment and total meal replacement (TMR) period, post-operative follow-up at each stage, red flags for escalation, the lab monitoring schedule, and daily micronutrient supplementation for both sleeve gastrectomy and Roux-en-Y gastric bypass.
A quick reference for registered dietitians supporting patients through the Western Zone Bariatric Surgery Program. Pair it with the patient-facing Nutrition Guide for Bariatric Surgery, and adjust to each patient’s needs.
Section 1 · Pre-Operative Nutrition
3+ months prior to surgery · 60–90 minutes
Screen with the BEDS-7 (Binge Eating Disorder Screener) or LOCES-Brief (loss-of-control eating). See the Physician Quick Reference for full BED screening and management.
Share the patient-facing Nutrition Guide for Bariatric Surgery. To connect patients with local dietitian support, use the Western Zone Care Map (shows dietitian availability by clinic).
Upon scheduling the surgery date · 1–2 months prior · 30–60 minutes
Section 2 · Post-Operative Nutrition
| Check-in post-op (week 1) | Early post-op (1–2 months) | Late post-op (6+ months) |
|---|---|---|
| Diet: advanced to full fluids with protein Fluids: ≥1.5–2 L/day GI: screen for red flags MV: started Extras: avoiding carbonated & caffeinated beverages |
Protein: minimum 60 g/day Fluids: ≥1.5–2 L/day, separated from meals by 30 min Meals: 3–5/day, slow / chew well GI: N/V, reflux, dumping MV: daily, tolerated Diet: advancing appropriately |
Protein: 1.2–1.5 g/kg/day goal body weight Fluids: ≥1.5–2 L/day, separated from meals by 30 min Meals: 3–5/day, planned snacks as needed Extras: caloric beverages, alcohol MV: adherence |
Section 2D
Section 2C
Post-op labs at 3, 6, and 12 months, then annually (per Obesity Canada post-operative management):
Section 3 · Supplementation
Section 3B
| Micronutrient | Daily supplementation | Notes / special populations |
|---|---|---|
| Vitamin B1 (thiamine) | 12 mg (50–100 mg if high risk) | If insufficient in MV, add a 50 mg B-complex supplement |
| Vitamin B9 (folate) | 400–800 mcg | Increase to 1000 mcg for preconception / pregnancy |
| Vitamin B12 | 350 mcg | May require alternative routes if malabsorptive issues persist |
| Vitamin C | 120 mg | — |
| Vitamin A | 5000–10,000 IU | Caution not to exceed upper limit if pregnancy is in future |
| Vitamin D | 3000 IU (75 mcg) | Adjust based on 25-OH vitamin D levels |
| Vitamin E | 15 mg | Monitor if deficiency risk |
| Vitamin K | 90 mcg | Some individuals may need higher doses |
| Calcium (citrate) | 1200–1500 mg | Prefer citrate; divided doses of no more than 500–600 mg separated by 2 h; separate from iron by 2 h |
| Magnesium | 400 mg | — |
| Iron | 18 mg (low risk); 45–60 mg (high risk) | Consider 45–60 mg/day if high risk (menstruating, previous low ferritin); adjust based on iron studies |
| Zinc | 8 mg | Zinc:copper ratio should be 8–15 mg : 1 mg |
| Copper | 1 mg | Important for zinc balance |
For a full list, see the Obesity Canada Clinical Practice Guidelines: Bariatric Surgery — Postoperative Management, Table 3.
More for Clinicians
The physician quick reference, the patient nutrition guide, the full bariatric surgery guide, and more.
Get in Touch
Questions about a referral, a clinical pathway, or collaborating across the network? Reach out — we’re glad to help.