What is the particle size for level 6 soft and bite sized diet for an adult?

October 19, 2025 •

4 min read

According to the International Dysphagia Diet Standardisation Initiative (IDDSI), the recommended maximum particle size for an adult on a level 6 soft and bite-sized diet is 1.5 cm by 1.5 cm. This specific sizing is crucial for individuals with chewing or swallowing difficulties, known as dysphagia, to minimize the risk of choking and make eating safer and more comfortable.

Quick Summary

The IDDSI framework specifies that food for an adult on a level 6 soft and bite-sized diet must be cut into pieces no larger than 1.5 cm by 1.5 cm. These foods must also be soft, moist, and tender, requiring moderate chewing. This particle size is designed to reduce choking risk for individuals with compromised chewing or swallowing abilities.

Key Points

Particle Size: The maximum particle size for an adult on a level 6 soft and bite-sized diet is 1.5 cm x 1.5 cm, roughly the width of a standard fork.
Texture and Moisture: Food must be soft, tender, and moist throughout, requiring moderate chewing before swallowing.
Softness Test: Use the fork pressure test, where the food should easily mash when pressed with a fork and not spring back to its original shape.
Safety Purpose: The restricted size and softness are designed to minimize the risk of choking and aspiration for individuals with swallowing difficulties.
Food Examples: Suitable foods include tender meats, soft-cooked vegetables, and moistened cereals, all cut to the correct size.
What to Avoid: Hard, stringy, crunchy, or crumbly foods, as well as those with skins, seeds, or nuts, should be avoided.

The International Dysphagia Diet Standardisation Initiative (IDDSI) developed a global framework to standardize food texture and drink thickness for individuals with dysphagia, or swallowing difficulties. A level 6 soft and bite-sized diet for an adult is prescribed for those who can chew but have difficulty biting off pieces of food safely. For this diet, the particle size is a primary safety consideration.

Maximum Particle Size for Adults

For adults following a level 6 diet, all solid food pieces must be no larger than 1.5 cm x 1.5 cm. This dimension is roughly equivalent to the width of a standard dinner fork or an adult thumbnail. This specific size is small enough to pass through the trachea without blocking it, significantly reducing the risk of asphyxiation. It is a critical guideline for ensuring mealtime safety for people with conditions like missing teeth, poorly fitting dentures, or certain neurological disorders.

Importance of Particle Size and Texture

Beyond just the size, the overall texture of the food is equally important for a level 6 diet. Food must be soft, tender, and moist throughout. The softness can be tested by pressing the food with the back of a fork; it should easily mash and change shape without springing back. This softness ensures that even with reduced chewing strength, the food can be safely broken down in the mouth before swallowing. Avoiding hard, crispy, or stringy foods is essential, regardless of their size.

Characteristics of a Level 6 Diet

A level 6 diet requires a specific combination of attributes to be safe and effective. The key characteristics are:

Moisture: Food must be moist, with no separate thin liquid. A sauce or gravy should be thick and smooth, not watery.
Softness: The food must be tender and easily mashable with a fork.
Consistency: A scooped sample of food should hold its shape on a fork or spoon.
No Separate Thin Liquid: The diet avoids foods that produce thin, watery liquid upon chewing, as this can increase choking risk.
No Biting Required: The food is pre-cut, so individuals do not need to bite into larger pieces.

How to Measure and Test Food

To ensure food meets the level 6 standard, caregivers and individuals should perform the fork and spoon pressure tests.

Fork Pressure Test: Press down on the food with a fork until the thumbnail on your thumb turns white. The food should squash easily and not spring back. This test ensures the food is soft enough.
Particle Size Check: Use a fork as a guide. The width of a standard dinner fork is a reliable way to check if food pieces are within the 1.5 cm x 1.5 cm guideline.
Spoon Pressure Test: Similar to the fork test, you should be able to cut or break down the food with the edge of a spoon using moderate pressure.

Common Level 6 Foods and Preparation

Proper preparation is key to making a wide variety of meals safe and appealing for a level 6 diet. Many everyday foods can be adapted to fit the required particle size and texture criteria.

Level 6 Food Examples

Meats: Tender meats, like slow-cooked beef or tender chicken, cut into 1.5 cm x 1.5 cm pieces and served with gravy or sauce. Flaky fish is also suitable.
Vegetables: Steamed or boiled vegetables, such as carrots or potatoes, that are cooked until tender and cut to the correct size.
Fruits: Soft, peeled fruits like bananas, ripe peaches, or canned pears, cut into bite-sized pieces.
Carbohydrates: Well-cooked pasta cut into small pieces, or moist rice with a thick sauce. Bread can be soaked or prepared as a soft sandwich with a moist filling.

Comparison of Level 5 and Level 6 Diets


Feature	IDDSI Level 5: Minced and Moist	IDDSI Level 6: Soft and Bite-Sized
Primary Goal	For individuals who need very little chewing, but can manage some minced food.	For individuals who can chew bite-sized pieces, but cannot bite off pieces from a larger item.
Particle Size (Adult)	Small, moist particles no larger than 4 mm (like a rice grain).	Soft, moist pieces no larger than 1.5 cm x 1.5 cm.
Chewing Required	Minimal chewing required.	Moderate chewing required.
Testing Method	Food should pass easily through a fork's prongs and mound on a spoon.	Food pieces must pass the fork pressure test and fit between the fork tines.
Appearance	Minced and uniform consistency.	Clearly separate, soft, bite-sized pieces.

Conclusion

The 1.5 cm x 1.5 cm particle size for an adult on a level 6 soft and bite-sized diet is a scientifically-backed standard from IDDSI, crucial for dysphagia management and patient safety. By adhering to both the size and the softness criteria, healthcare professionals and caregivers can provide safe, palatable meals that promote nutrition and enhance quality of life. This requires consistent preparation and testing to ensure all food items, from meats to vegetables, meet the specific texture and size requirements outlined by the framework. Adherence to these guidelines is not merely a suggestion but a critical measure for preventing choking and aspiration in vulnerable individuals. For more detailed information on the IDDSI framework and testing methods, the official IDDSI website provides comprehensive resources and guides.

Frequently Asked Questions

For an adult on a level 6 soft and bite-sized diet, all solid food pieces must be cut or prepared to be no larger than 1.5 cm x 1.5 cm.

You can perform the fork pressure test. Press down on the food with the back of a fork; it should mash easily and remain mashed when the fork is lifted.

This size is important because it is small enough to pass safely through the trachea if accidentally swallowed whole, significantly reducing the risk of choking or asphyxiation.

While not a solid particle, sauces and gravies should be thick and smooth. The food pieces should not be in a separate, thin liquid, as this creates mixed consistencies which can be unsafe.

Steamed or boiled vegetables, like carrots, sweet potatoes, and cauliflower, are suitable. They should be cooked until tender and then cut into 1.5 cm pieces.

Yes, but it must be properly prepared. Soft, soaked bread, such as bread softened with milk or served as a soft sandwich with a moist filling, is acceptable. Dry or seeded breads are not.

Yes, moderate chewing is still required for a level 6 diet. However, the food is pre-cut into bite-sized pieces, so the person does not need to use their teeth to bite off chunks of food.