What is a dysphagia diet level 0? Understanding Thin Liquids in the IDDSI Framework

October 17, 2025 •

3 min read

Millions of people worldwide experience dysphagia, or difficulty swallowing, which is why a global standard called the International Dysphagia Diet Standardisation Initiative (IDDSI) was developed. This framework includes a dysphagia diet level 0, which refers to the thinnest consistency of liquids, similar to water.

Quick Summary

A dysphagia diet level 0 is defined by the IDDSI framework and includes thin liquids like water, juice, and coffee. This diet is suitable for individuals with swallowing difficulties who can safely manage fast-flowing liquids. Correct assessment by a healthcare professional is vital to ensure patient safety and adequate hydration.

Key Points

Thin Liquids: A dysphagia diet level 0 consists of un-thickened, fast-flowing liquids, like water or tea.
IDDSI Framework: This level is part of the International Dysphagia Diet Standardisation Initiative, a global standard for dysphagia diets.
Swallowing Ability: Level 0 is intended for individuals who can safely manage liquids of this thin consistency.
Professional Assessment: An individual’s appropriate diet level must be determined by a speech-language pathologist or other qualified clinician.
Aspiration Risk: For patients at risk of aspiration, liquid levels higher than 0 are prescribed to slow the flow and improve control.
Consistency Check: The IDDSI Flow Test can be used to verify that a liquid meets the criteria for Level 0.
Hydration: This diet allows for normal hydration with a wide variety of typical beverages for those who can tolerate it safely.

Understanding the IDDSI Framework

The International Dysphagia Diet Standardisation Initiative (IDDSI) is a global, standardized framework for describing and classifying texture-modified foods and thickened liquids for people with dysphagia. It uses a scale from 0 to 7 to ensure that healthcare professionals, caregivers, and patients use a consistent terminology, reducing confusion and improving safety. The framework provides a continuum of levels for both liquids (Levels 0-4) and foods (Levels 3-7). The IDDSI framework is designed to improve safety and care for individuals with dysphagia across all ages and settings.

What Defines a Dysphagia Diet Level 0?

At the base of the IDDSI framework is dysphagia diet level 0, which is designated for "thin" liquids. This means the liquid has the same consistency and flow rate as water. These liquids move quickly and require the individual to have sufficient control to manage their speed in the mouth and throat. This level is typically recommended for individuals who do not have swallowing problems with liquids or whose swallowing difficulties do not require thickened liquids.

Characteristics of Level 0 Liquids

Flows like water: The liquid is completely un-thickened and flows freely.
Fast flow: It travels quickly through a syringe, straw, or cup.
No lumps: It is a uniform, homogenous liquid with no particles or pulp.
IDDSI Flow Test: For verification, less than 1 mL of the liquid should remain in a 10 mL syringe after 10 seconds of flow.

Examples of Level 0 Liquids

Water
Milk (un-thickened)
Fruit juice (without pulp)
Tea and coffee
Sodas and soft drinks
Clear broths
Breast milk or infant formula

Who Is a Level 0 Diet For?

An individual is placed on a level 0 diet based on a comprehensive clinical assessment by a speech-language pathologist or other healthcare provider. This is typically the standard for individuals without swallowing issues. However, for those with dysphagia, it is only appropriate if their assessment shows they can safely and effectively swallow thin liquids.

Conversely, many individuals with dysphagia may be prescribed thicker liquid levels to reduce the risk of aspiration, where liquids enter the airway instead of the esophagus. The decision to prescribe or not prescribe a level 0 diet is crucial for preventing serious health complications like aspiration pneumonia.

Comparison of IDDSI Liquid Levels

The IDDSI framework differentiates liquids based on their viscosity, or thickness. This table highlights the primary differences between the first five liquid levels:


IDDSI Level	Description	Key Characteristic	Examples
0	Thin	Flows like water; fast flow	Water, juice, tea, coffee
1	Slightly Thick	Thicker than water; still flows through a teat/straw	Some juice drinks or melted ice cream
2	Mildly Thick	Flows off a spoon; sippable with effort	Nectar, buttermilk, some milkshakes
3	Moderately Thick	Can be drunk from a cup; difficult to sip through straw	Honey-like consistency, some smoothies
4	Extremely Thick	Cannot be drunk from a cup; requires a spoon	Pudding, thick puree

Management and Nutritional Considerations

Even on a level 0 diet, proper nutrition and hydration are vital, especially for those with health conditions causing dysphagia. In cases where thin liquids are tolerated but food textures are restricted, a dietitian may recommend supplements or a specific meal plan to ensure adequate caloric and nutrient intake. Regular assessment by healthcare professionals is important to ensure the diet remains appropriate for the individual's changing needs. For individuals who cannot manage thin liquids, clinicians may recommend commercially available thickening agents to achieve the correct and safe consistency.

The Role of the Healthcare Team

Managing a dysphagia diet is a collaborative effort involving a team of healthcare professionals.

Speech-Language Pathologists (SLP): Conduct swallowing assessments and determine the appropriate liquid and food levels.
Registered Dietitians (RD): Ensure the diet provides adequate nutrition and hydration for the individual's health needs.
Physicians: Oversee the overall medical management and any underlying causes of dysphagia.
Caregivers: Implement the diet plan and monitor for any signs of swallowing difficulties.

Conclusion

Understanding what is a dysphagia diet level 0 is fundamental for anyone involved in managing swallowing difficulties. As the lowest level in the IDDSI framework, it comprises thin, fast-flowing liquids suitable for individuals with no or minimal issues handling such consistencies. For those who cannot manage thin liquids, thicker alternatives exist within the IDDSI continuum. The proper, consistent application of the IDDSI framework is a crucial step toward ensuring patient safety, preventing aspiration, and maintaining adequate nutrition and hydration. Consistent consultation with a healthcare team is the best practice for a successful and safe dysphagia management plan..

IDDSI's official website offers comprehensive resources on the framework.

Frequently Asked Questions

The primary characteristic of a dysphagia diet level 0 is its thin, fast-flowing consistency, similar to water.

A Level 0 diet is for individuals who, based on a clinical assessment, can safely manage thin liquids without a high risk of aspiration or swallowing difficulties.

Examples of Level 0 liquids include water, milk, coffee, tea, and juice without pulp.

A Level 0 liquid is un-thickened and flows the fastest, unlike higher levels (1-4) which are progressively thicker to slow the liquid's flow.

The IDDSI Flow Test is a method using a 10 mL syringe to check a liquid's thickness. For Level 0, less than 1 mL should remain in the syringe after 10 seconds.

It is only safe if a healthcare professional, such as a speech-language pathologist, has assessed the individual and determined they can safely manage thin liquids.

If someone who requires thickened liquids accidentally drinks a Level 0 liquid, they are at an increased risk of aspiration, where the liquid enters the lungs, potentially causing pneumonia.