Fact sheetDiet specifications

Published on 1 Nov 2019

Fluid diet - bariatric surgery - full

This document is part of the ACI Diet Specifications for Adult Inpatients. It is not to be used for patient education.


To provide a diet appropriate for patients immediately after bariatric (weight loss) surgery, to prevent gastrointestinal symptoms, complications and to replace or maintain the body’s fluid balance.


This diet includes only fluids or foods that liquefy at room temperature. All carbonated liquids are excluded. Fluids containing fat are limited. Only three items are provided at each meal with a maximum of 100–120mL per item with the exception of water.


Where appropriate, clinicians may consider ordering this diet for patients:

  • Post-bariatric surgery, as clinically indicated or as per the surgeon’s recommendations (e.g. may be commenced after Fluids - Bariatric surgery – clear diet or 1–3 days post-surgery).

Nutritional adequacy

This diet is inadequate in all nutrients and should not be used as the sole source of nutritional support for more than three days. Patients will require assessment and monitoring by a dietitian (note: assessment may occur pre or post-surgery). If used for more than three days, patients require a reduced fat, ≥3.5g protein/100ml liquid nutrition supplement recommended by a dietitian. Patients will require vitamin and mineral supplementation if length of stay > 3 days and longterm; chewable or liquid forms are preferable.


Patients do not receive a menu. For best tolerance patients should not use straws, should take small sips, start with liquids and sip them slowly throughout the day. To prevent dehydration, patients should sip low-energy fluids slowly throughout the day (30–60mL over 30 minutes), aiming for 1–1.5L per day. To prevent hypoglycaemia, the patient’s insulin regimens should be reviewed due to minimal carbohydrate provision. To prevent unwanted catabolism in adolescents and adults the protein content should be reviewed by a dietitian. Patients should be provided education and encouraged to avoid caffeine. One 100–120ml serve of tea or coffee per day is allowed. Commercial thickening agents are a source of fibre.


This diet is suitable for use in adolescents (≥15 years) when combined with an age-appropriate diet. However, it is noted that surgery can be considered at 14 years of age in exceptional circumstances.

Specific menu planning guidelines

Allowed Not allowed
Hot main dishesNone-
Sauces, graviesNone -
Starchy vegetables / pasta / riceNone -
SoupsSoup with ≤ 4.5g fat and ≤ 1.5g fibre per 100ml serve without visible food pieces including homogenised or pureed soups

Soups with visible food pieces

Cream, tomato or spicy soups

Salads, dressingsNone-
Breads, cerealsNone -
Hot breakfast choicesNone -
YoghurtSmooth fat-free, smooth low-fat or natural yogurt or drinking yoghurt without food piecesAll others
Milk and cheeseSkim milk

All other milk

All cheeses



Low-joule cordial

Strained vegetable juices

One 100–120ml serve of tea/coffee per day (with or without skim milk)

All others including orange, pineapple, tomato and prune juices, and carbonated fluids


Commercial liquid supplements containing ≤ 4.5g fat, ≥ 3.5g protein and ≤ 1.5g fibre per 100ml

Commercial liquid thickened fluids containing ≤ 4.5g fat and ≥ 3.5g protein per 100ml

Low-joule ice blocks

Pepper, sweetener

Note: Milk powder or protein powder may be added to drinks or soups to increase protein content

Cream, sugar and salt

Confectionary and chewing gum

Other commercial nutritional supplements

Other commercial thickened fluids


  1. Dietitians Association of Australia. Nutrition manual. 9th ed. Canberra: DAA; 2014.
  2. Snyder-Marlow G, Taylor D, Lenhard J. Nutrition care for patients undergoing laparoscopic sleeve gastrectomy for weight loss. Journal of The American Dietetic Association. 2010;110:600-7.
  3. Parkes E. Nutritional management of patients after bariatric surgery. Am J Med Sci. 2006;331:207-13.
  4. Mechanick J, Kushner R, Sugerman H, et al. American Association of Clinical Endocrinologists, The Obesity Society, and The American Society for Metabolic and Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient. Obesity. 2009;17(1):S3–S72.
  5. Aills, L, Blankenship J, Buffungton C, et al. ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient. Surgery for Obesity and Related Diseases. 2008(4);S73-S108.
  6. Shannon C, Gervasoni A, Williams T. The bariatric surgery patient: Nutritional considerations. Australian Family Physician. 2013;42(8):547-552.
  7. Dagan S, Goldenshluger, Globus I, et al. Nutritional Recommendations for Adult Bariatric Surgery Patients: Clinical Practice. American Society for Nutrition. 2017;8:382-94.
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