For Surgery Prep + Recovery


Best Nutrition Approach


For surgery prep + recovery, the “best” nutrition approach is usually peri-operative oral nutrition supplements (ONS) aligned with ERAS (Enhanced Recovery After Surgery) guidance—but the exact plan must match the surgeon/anesthesia instructions (especially fasting, diabetes meds, kidney disease, fluid restrictions).

Here’s what patients most commonly use, in a practical way:

What’s best to use pre-op (days to 2 hours before)

1) A high-protein ONS (meal-replacement style)

Use if appetite is low, weight loss is happening, or the patient is older/frail.

  • Goal is typically high protein and enough calories to avoid “running a deficit.”
  • Surgical nutrition guidelines emphasize avoiding underfeeding and using ONS in at-risk patients. (espen.org)

Practical use: 1–2 shakes/day for ~5–14 days pre-op (longer if malnourished/high risk).

2) Immunonutrition (IMN) for some major operations

For major abdominal surgery (often cancer or GI surgery), many protocols use an “immune-modulating” formula containing things like arginine + omega-3 fatty acids + nucleotides for ~5–7 days pre-op. (ScienceDirect) (Some evidence is mixed by surgery type, so this is best decided by the surgical team/dietitian.) (OUP Academic)

3) A clear carbohydrate drink shortly before surgery (only if allowed)

Many ERAS pathways include clear carbohydrate loading up to ~2 hours before anesthesia (reduces prolonged fasting; may improve early recovery metrics). (ASPEN)

Important: This is not for everyone—it may be modified/avoided in some patients (e.g., certain diabetes regimens, delayed gastric emptying, high aspiration risk). Always follow anesthesia instructions.

4) Fasting rules (don’t “wing it”)

Common guidance: clear liquids up to 2 hours before anesthesia; light meal/nonhuman milk up to 6 hours before. Your hospital may give stricter rules—follow theirs. (ASA Headquarters)

What’s best to use post-op (first days to weeks)

1) Early oral intake + high protein focus

Guidelines generally favor early oral feeding when feasible, and many ERAS nutrition pathways stress that hitting the protein target matters more than total calories early on. (espen.org)

Practical use: high-protein shakes 1–3×/day until normal meals are back.

2) Consider continuing immunonutrition after major abdominal surgery

Some ERAS nutrition pathways suggest IMN for ~7 days post-op in major abdominal surgery patients. (ASPEN)

3) If the patient can’t eat enough, escalate early

If oral intake stays low (often defined as < ~50% of needs), many protocols move to early enteral feeding (tube feeding) rather than “waiting it out.” (ASPEN)

A simple “best practice” shopping list (what to ask for)

  • High-protein oral nutrition supplement (ONS) (or a complete meal shake with extra protein)
  • Clear carbohydrate loading drink (only if the hospital/ERAS plan says yes)
  • Immunonutrition formula (arginine + omega-3 + nucleotides) if the surgery type/team recommends it
  • Optional add-ons (as tolerated): fiber (if not contraindicated), electrolytes, vitamin D only if deficient/clinician advised

Quick safety flags (when to involve the team before choosing a product)

  • Diabetes / insulin or SGLT2 meds
  • Kidney disease (protein/electrolytes like potassium/phosphate matter)
  • Heart failure / fluid restriction
  • Swallowing issues / aspiration risk
  • Bowel surgery with restrictions (temporary low fiber, etc.)

https://www.espen.org/files/ESPEN-Guidelines/ESPEN_practical_guideline_Clinical_nutrition_in_surgery.pdf?utm_source=chatgpt.com