IDDSI levels explained: dysphagia diets made clear

By the DieticiansWorldwide.com editorial team · 18 October 2026 · Clinical nutrition

What IDDSI is, and why it replaced local terms

Dysphagia means difficulty swallowing. The paper that introduced the IDDSI framework estimated that it affects about 8% of the world's population, roughly 590 million people (Cichero and colleagues, Dysphagia 2017). For many of them, the main safety measure is changing the texture of food and the thickness of drinks, so that each mouthful is easier to control and less likely to be inhaled or to cause choking.

Before IDDSI, every country, and often every hospital, had its own words for those textures. The developers surveyed existing practice and received 2,050 responses from 33 countries. They found 54 different names in use for food texture levels and 27 for liquid thickness. "Custard thick" in one ward could mean something different in the next, and a care home might use another scale again.

IDDSI was founded in 2013 to fix that. After a systematic review and two rounds of international consultation, the framework was released at the end of 2015 and described in full in the 2017 paper as a continuum of eight levels identified by numbers, text labels and colour codes. The current Complete IDDSI Framework detailed definitions are version 2.2, dated 2026, and are published under a Creative Commons licence.

The eight IDDSI levels at a glance

Drinks and foods share one numbered scale. Levels 3 and 4 appear on both sides, because a liquidised food and a moderately thick drink behave the same way, as do a pureed food and an extremely thick drink.

All descriptions and test results are from the IDDSI Framework detailed definitions, version 2.2. There is also a separate category of transitional foods, explained below.

Drinks: Levels 0 to 4

For drinks, IDDSI uses the IDDSI Flow Test. A standard 10 ml slip-tip syringe is filled to the 10 ml line with the nozzle covered, the nozzle is released, and after 10 seconds the flow is stopped. The amount left in the syringe tells you the level. IDDSI warns that syringes differ, and specifies a 10 ml scale that measures 61.5 mm, so testers should check the syringe before using it.

• Level 0, Thin. Less than 1 ml remains. Flows like water and is suitable for people with the functional ability to manage all types of liquid safely.
• Level 1, Slightly Thick. 1 to 4 ml remains. IDDSI notes it is similar to most commercially available anti-regurgitation infant formulas and is often used in children, as well as in adults for whom thin drinks flow too fast.
• Level 2, Mildly Thick. 4 to 8 ml remains. Sippable and pours quickly from a spoon, but needs mild effort through a standard straw. It may suit people with slightly reduced tongue control.
• Level 3, Moderately Thick. More than 8 ml remains. Can be drunk from a cup, needs moderate effort through a straw, and drips slowly in dollops through the prongs of a fork.
• Level 4, Extremely Thick. The Flow Test does not apply, because nothing flows. It is tested with the fork and spoon methods used for pureed food.

Testing should be done on drinks as they will be served, especially at the serving temperature, which IDDSI singles out as the condition that matters most.

Does thicker mean safer?

Not automatically. A systematic review that informed IDDSI's development found two consistent trends: thicker liquids reduce the risk of material entering the airway (penetration and aspiration), but they also increase the risk of residue left in the throat after swallowing (Steele and colleagues, Dysphagia 2015). Residue can itself be inhaled later. The review also found that the literature was not strong enough to set precise viscosity boundaries linked to clinical outcomes.

That trade-off is why drink thickness is an individual clinical decision, usually based on a swallowing assessment, and why the "thickest possible" is not the default. Whatever the level, fluid intake needs watching. The NHS notes that, over time, dysphagia can lead to weight loss, dehydration and repeated chest infections (NHS, swallowing problems).

Foods: Levels 3 to 7

Level 3, Liquidised

Smooth, with no bits, and cannot hold its shape on a plate. It can be eaten with a spoon but not a fork, because it drips through the prongs. No chewing is needed. IDDSI gives runny infant cereals and runny pureed fruit as examples of foods that may fit this level, and notes that some sauces, gravies and syrups do, if confirmed by the Flow Test.

Level 4, Pureed

Usually eaten with a spoon. It holds its shape, can be piped or moulded, and shows only very slow movement under gravity. It must have no lumps, must not be sticky, and liquid must not separate from the solid. No biting or chewing is required.

Level 5, Minced & Moist

Soft and moist, with small visible lumps that are easy to squash with the tongue, and no separate thin liquid. For adults, lumps must be no more than 4 mm wide and no more than 15 mm long; for children, no more than 2 mm wide and 8 mm long. IDDSI notes that 4 mm is about the gap between the prongs of a standard dinner fork, which makes the fork a handy measuring tool. Minimal chewing is needed. Meat is finely minced and served in a smooth, thick sauce, and regular dry bread, sandwiches and toast are excluded.

Level 6, Soft & Bite-Sized

Soft, tender and moist throughout, cut into pieces no larger than 1.5 cm by 1.5 cm for adults and 8 mm for children. A knife is not needed to cut it. Unlike Level 5, chewing is required before swallowing, so this level needs the ability to chew and to keep food under control in the mouth. Regular dry bread is still excluded, and stir-fried vegetables are often too firm.

Level 7, Easy to Chew and Regular

Level 7 is everyday food. Regular has no texture restrictions. Easy to Chew includes normal foods of soft and tender textures but excludes hard, tough, chewy, fibrous, stringy, crunchy or crumbly bits, pips, seeds, husks and bones. Because food pieces at Level 7 can be any size, IDDSI warns that Easy to Chew could present a choking risk for people with a clinically identified increased risk of choking, and that where mealtime supervision is needed, it should only be used under the strict recommendation and written guidance of a qualified clinician.

Transitional foods

Transitional foods start as one texture, usually firm and solid, and change into another when moisture is added or the temperature changes. IDDSI lists examples such as ice chips, wafers and some biscuits. They are used in developmental teaching and in rehabilitation of chewing skills, for example after a stroke, and only when a specialist has assessed them as suitable.

How do you test IDDSI Level 4?

Level 4 is checked with two tests, both described in the framework.

1. Fork Drip Test. Scoop a sample with a fork. It should sit in a mound or pile above the fork. A small amount may flow through and form a short tail below the prongs, but it should not flow or drip continuously.
2. Spoon Tilt Test. Fill a spoon and tilt or turn it sideways. The sample should hold its shape, then fall off in a single spoonful. A very gentle flick may be needed, and a thin film left on the spoon is acceptable, as long as you can still see the spoon through it. If the sample sticks firmly to the spoon, it is too thick and sticky.

When a fork is pressed on the surface of a Level 4 food, the prongs should leave a clear pattern or an indentation. IDDSI also gives a finger test for settings without cutlery: the food slides smoothly between the fingers and leaves a noticeable coating.

Minced & Moist versus Pureed: the key differences

These two levels are the ones most often confused, and the difference matters for safety.

The step from Level 4 to Level 5 introduces lumps, however small, and that requires more tongue control and some chewing. A person who coughs or tires on minced food may need to stay on pureed food until their swallowing team reassesses them. In the other direction, keeping someone on pureed food for longer than necessary narrows their diet and can reduce how much they want to eat.

Foods that pose a choking risk

The framework includes a list of food textures linked to choking in international autopsy reports. It is a useful checklist for anyone preparing meals for a person with dysphagia, even before a texture level is set.

• Hard or dry: nuts, raw carrots, hard crusty rolls.
• Fibrous or tough: steak, pineapple.
• Chewy or sticky: sweets, cheese chunks, marshmallows, sticky mashed potato, nut butter, sticky rice cakes.
• Crunchy or crispy: raw apple, popcorn, crisp bacon, some dry cereals.
• Crumbly: dry cakes, dry biscuits and scones.
• Round or long: grapes and sausages.
• Floppy: lettuce, thinly sliced cucumber, baby spinach.
• Mixed thin and thick: soup with pieces, cereal with milk.
• Juicy: watermelon, where juice separates from the solid in the mouth.

How to read a swallowing plan

A swallowing plan from a speech and language therapist usually gives two separate levels, one for food and one for drinks, because they are assessed separately. A plan might specify, for example, a food level of 5 Minced & Moist and a drink level of 2 Mildly Thick, along with mealtime instructions such as sitting upright, taking small mouthfuls, eating slowly or being supervised.

When you read one, check:

• Both numbers and both names. The numbers and names should match the IDDSI definitions. Old terms such as "soft diet" or "custard thick" are a warning sign that the plan has not been updated.
• Whether thickener is involved, and how it should be prepared. Thickeners vary, so follow the product instructions and test the result.
• Mealtime strategies, which can matter as much as texture.
• Medicines. Ask a pharmacist how tablets and liquid medicines should be given, because crushing or mixing them into food is not always safe.
• The review date. Swallowing can improve or decline, so plans should be reassessed.

If someone cannot swallow safely enough to meet their needs at any texture, the team may consider tube feeding. NICE advises that in the acute setting, for example after a stroke, people unable to swallow safely or take enough energy and nutrients by mouth should have an initial 2 to 4 week trial of nasogastric tube feeding while specialists assess the outlook (NICE CG32). Tube feeding is explained in our guide to enteral nutrition; the rarer step of intravenous feeding is covered in parenteral nutrition.

Keeping texture-modified diets nutritious

Texture modification protects the airway but can harm nutrition. Pureeing and mincing often mean adding liquid, which can dilute the energy and protein in each spoonful, and food that looks unfamiliar can put people off eating. That is where the dietitian's role sits within the swallowing team.

Typical dietetic strategies include fortifying purees with energy and protein, offering smaller and more frequent meals, using piping and moulding so food looks like the dish it came from, and monitoring weight. Recipe and presentation ideas are in our guide to pureed and texture-modified meals. Protein matters particularly for older adults at risk of muscle loss, covered in our guide to sarcopenia, and for people with pressure ulcers or surgical wounds, covered in nutrition for wound healing.

Someone whose swallowing problem went unnoticed for weeks may have eaten very little in that time, and that raises the risk when full meals or feeds begin again. Our guide to refeeding syndrome explains the warning signs and why the first days need medical monitoring. Long periods on a restricted diet can also leave micronutrient gaps; vitamin B12 deficiency is common in older adults and easily missed.

Protocol variation: how countries and hospitals differ

IDDSI is international, but adoption has been uneven, and local practice still varies.

In England, NHS Improvement issued a patient safety alert in June 2018 asking all organisations providing NHS-funded care to move to the IDDSI framework and stop using the term "soft diet", with work to be completed by 1 April 2019 (NHS England, patient safety alert). A review of national incident reports had found seven cases where patients appeared to have come to significant harm from confusion over "soft diet", including choking and aspiration pneumonia; two patients died. The alert also asked that IDDSI food descriptors be used for patients without dysphagia who need a modified texture for other reasons, such as lost dentures or jaw surgery. For how dietetic practice is organised in Britain, see our United Kingdom country guide.

In Australia, IDDSI has been implemented since May 2019, replacing the previous national standardised terminology, according to the Australian IDDSI implementation report. Our Australia country guide covers dietetic accreditation and practice there.

Elsewhere, hospitals may still be in transition, may use IDDSI for food but older terms for drinks, or may run several thickener products with different preparation instructions. When patients move between hospital, care home and home, the swallowing plan should travel with them in IDDSI terms.

Staffing: who sets the level and who orders the diet

In most systems, the speech and language therapist assesses swallowing and recommends the food and drink levels, the dietitian makes sure the diet meets nutritional needs, and catering staff and carers prepare and check the textures. IDDSI designed its tests so that people with dysphagia, carers, clinicians, food service staff and industry can all use them to confirm a texture.

Who formally orders the diet varies. In US hospitals, federal conditions of participation say all patient diets, including therapeutic diets, must be ordered by a practitioner responsible for the patient's care, or by a qualified dietitian or qualified nutrition professional as authorised by the medical staff and in line with state law (42 CFR 482.28). In the UK and Australia, local policy decides who can record or change a texture order. IDDSI does not set staffing levels, and the framework cannot make up for too few specialists. What it does is reduce the risk of error when several professions touch the same plan, which is exactly the problem the English safety alert described.

Dysphagia practice improves when professionals share what works. Dietitians, speech and language therapists, catering leads and aged-care teams can compare texture protocols and audit tools with colleagues abroad through our professional network.

Join the DieticiansWorldwide.com professional network

If you care for someone at home and want help making meals within their current plan more varied or nourishing, book a session with a registered dietitian. Any change to the texture or drink level itself must come from the speech and language therapist.