Fibre-Rich Foods and Practical Ways to Increase Fibre After Bariatric Surgery

Fibre-Rich Foods and Practical Ways to Increase Fibre After Bariatric Surgery

by Nicole Freebairn, Registered Nutritionist

If you’ve already heard about the importance of dietary fibre, the next question is usually a practical one: what should I actually eat - and how much?

Following bariatric surgery, your stomach capacity, digestion, and tolerance change significantly. This means increasing fibre isn’t about simply adding more whole grains or vegetables. Instead, it’s about choosing the right foods at the right stage, with a focus on choosing fibre sources that are appropriate for each stage of recovery and individual tolerance.

This article focuses on where to find fibre in foods and how to increase fibre intake safely and effectively at each stage after bariatric surgery.

A Quick Refresher: Why Fibre Matters Post Surgery

Adequate dietary fibre can support:

• Blood sugar stability 

• More favourable cholesterol levels

• Gut health and bowel regularity

• Satiety (keeps you feeling fuller for longer) 

You can read more about the importance of dietary fibre here. 

How to Increase Fibre at Different Stages After Bariatric Surgery

Early Stage (Weeks 2 - 6): Gentle and Gradual

At this stage, food tolerance is limited and fibre needs to be soft, hydrated, and low volume. Importantly, we also prioritise fibre-rich foods that also contribute protein, as protein remains the top nutritional priority in the early stages after surgery.

Practical options include:

• Smooth porridge (made with milk and added protein powder)

• Avocado mashed through canned salmon or tuna, or edamame beans

• Protein-based casserole or soups blended with legumes

• Tric Soluble Fibre added to fluids 

Tips:

• Prioritise protein first, then add small amounts of fibre where tolerated

• Introduce one new fibre source at a time

• Avoid raw veggies (apart from avocado) 

• Keep portions small and textures smooth

• Stop at the first sign of discomfort

• Using a bariatric-approved fibre supplement daily is important to support bowel regularity at this stage

Mid Stage (6 Weeks - 6 Months): Building Variety

As capacity and tolerance improve, you can gradually start expanding your fibre sources.

Try:

• Beans, legumes, or quinoa added to meals 

• Chia or ground flaxseed added to yoghurt or smoothies 

• Nuts or nut butters included in small amounts 

• From 3 months, start to include some fresh fruit (as advised by your nutritionist) 

Tips:

• Increase fibre slowly over weeks

• Chew thoroughly

• A fibre supplement is often still recommended to help meet fibre needs while portions are limited 

Long-Term Stage (6+ Months): Sustainable Fibre Habits

Long-term success comes from consistency rather than large amounts of fibre at once.

Aim to:

• Include a source of fibre at each meal

• Rotate fibre foods to support gut diversity

• Pair fibre with protein and healthy fats

• Use supplements strategically if food intake remains limited

Practical Tips to Increase Fibre Without Discomfort

• Go slow: rapid increases are the most common cause of bloating or gut upsets

• Hydrate well: fibre needs fluid to move through the gut properly

• Choose cooked vegetables over raw initially

• Grind or soak seeds to improve tolerance (for example, ground flaxseed or chia puddings)

• Increase fibre variety gradually rather than big changes at once

Dietary fibre is not a one-sized-fits-all. If you experience any gut upsets, such as constipation or diarrhoea, speak to your nutritionist for more individualised guidance. 

When Are Fibre Supplements Helpful?

Fibre supplements can be useful when food intake is limited, tolerance is variable, or bowel habits are inconsistent - all of which are common after bariatric surgery.

A supplement such as Tric Soluble Fibre can be an easy way to support daily fibre intake without adding food volume. It can be mixed into water, protein shakes, or foods such as yoghurt, making it practical at any stage post‑surgery.

As with all supplements:

• Start with a small amount

• Increase gradually

• Ensure adequate fluid intake

• Use alongside, not instead of, fibre‑containing foods

Your bariatric dietitian or nutritionist can help determine whether a fibre supplement like Tric Soluble Fibre is appropriate for you and how to use it safely.

Fibre Cheat Sheet: Easy Reference Guide

Fibre is found exclusively in plant-based foods, such as vegetables, fruit, nut, seeds, legumes and whole grains. Below is a simple, bariatric‑friendly guide to common fibre‑containing foods. Values are approximate and will vary by preparation.

Fibre Content of Common Foods (Approximate)

•  ¼ C Rolled oats (dry) = 3 g

• 1 Tbsp Chia seeds = 4 g

• 1 Tbsp Ground flaxseed = 3.5 g

• 1 medium Kiwifruit = 2-3 g

• ½ C Berries = 2-4 g

• ¼ medium Avocado = 2 g 

• ½ C Cooked peas = 4.4 g

• ½ C Edamame beans = 4 g 

• ¼ C Lentils = 3-4 g

How Much Fibre Should You Aim For?

General population guidelines suggest 25-30 g of fibre per day, but after bariatric surgery this needs to be adapted based on individual tolerance and post-op stage. Not all fibre-containing foods behave the same way in the gut, so it can be helpful to work with a bariatric nutritionist for personalised guidance. 

What Does This Look Like in a Day?

A fibre‑supportive day might include:

• Breakfast: Protein porridge with 1 Tbsp chia seeds (6-8 g)

• Lunch: Soup with protein, cooked vegetables and lentils (4-6 g)

• Snack: Kiwifruit with yoghurt (2-3 g)

• Dinner: Protein with cooked vegetables (3-4 g)

Key Takeaway

After bariatric surgery, increasing fibre is less about eating “more” and more about eating smarter. Consistency matters more than hitting an exact number. By gradually increasing your intake of fibre-rich foods you can help to support digestion, metabolic health, and long-term weight management.

At Tailor Clinics, our nutrition team provides individualised guidance to help you build fibre intake safely and sustainably at every stage of your bariatric journey. If you would like to book in with our nutritionists, please contact reception@tailorclinics.co.nz to request an appointment. 

Disclaimer: this blog post is intended for educational purposes only and does not replace individual medical advice. For more support please always seek the guidance of your relevant health practitioners.