What foods are not considered solids?

January 3, 2026 •

4 min read

According to the Transportation Security Administration (TSA), any food that can be poured, squeezed, spread, or sprayed is not considered solid. This broad definition highlights that the classification of what foods are not considered solids is not always as simple as it seems, extending beyond typical liquids to include gels, purees, and even some frozen desserts.

Quick Summary

This article explores the categories of non-solid foods, from clear and full liquids used in medical diets to semi-solid items like yogurt and pudding. It details how classifications vary based on context, such as for dietary restrictions or airport security, and provides numerous examples.

Key Points

Medical Diets: Non-solid foods are medically categorized into clear liquids (transparent, pulp-free) and full liquids (everything liquid or melting at room temperature).
Semi-Solids: This category includes thick, soft, or mashed foods like pudding, yogurt, and applesauce, used for transitioning to solids or managing swallowing difficulties.
TSA Classification: For travel, the TSA defines non-solids as anything that can be squeezed, spread, or poured, regardless of its culinary classification.
Travel Restrictions: Many common foods like peanut butter, hummus, and yogurt are subject to the TSA's 3-1-1 liquid rule in carry-on baggage.
Context is Key: Whether a food is considered solid or not varies by context, from medical needs that consider digestibility to travel rules that focus on physical state.
Frozen Foods: Foods like ice cream and popsicles are considered full liquids in a medical diet because they melt, but they are treated as liquids for travel purposes.

Understanding the Different Classifications of Non-Solid Foods

The world of food is not strictly divided into solids and liquids. The reality is far more nuanced, with many foods existing in a grey area. Understanding the various categories of non-solid foods is essential for several reasons, including managing medical diets, navigating travel restrictions, and preparing meals for infants or those with swallowing difficulties. The simplest classification often used in a medical context is the distinction between clear liquids, full liquids, and semi-solid or pureed diets. However, other contexts, such as travel, apply different criteria.

The Clear Liquid Diet

A clear liquid diet is the most restrictive of the non-solid food diets, often prescribed before medical procedures like a colonoscopy or after certain surgeries. These foods are transparent, easy to digest, and leave no undigested residue in the intestinal tract. This helps to keep the digestive system clear and allows for proper medical examination.

Examples of Clear Liquid Foods

Water (plain, carbonated, or flavored)
Clear, fat-free broth (bouillon or consommé)
Pulp-free fruit juices (e.g., filtered apple or white grape juice)
Gelatin (like Jell-O)
Clear sodas (e.g., ginger ale, Sprite)
Plain ice pops with no fruit pieces or cream
Coffee or tea without milk or cream
Honey or sugar

The Full Liquid Diet

A full liquid diet offers more nutritional variety than a clear liquid diet and is used for patients transitioning from a clear liquid diet or for those with specific chewing or swallowing difficulties. This diet includes all foods that are liquid at room temperature. This means that frozen items like ice cream and popsicles are allowed, provided they melt into a smooth liquid.

Examples of Full Liquid Foods

Milk and dairy products (milkshakes, yogurt without solids)
Custard and pudding
Strained cream soups and broths
All juices, including those with pulp
Cooked, refined cereals like cream of wheat or thinned oatmeal
Smoothies made without seeds or nuts
Liquid nutritional supplements (e.g., Boost, Ensure)
Butter and margarine melted into other liquids

Semi-Solid and Pureed Foods

The line between liquid and solid food blurs further with semi-solids and purees. These foods are soft, mashed, and often smooth in consistency, requiring minimal chewing. This diet is common for infants introducing solid foods or for adults recovering from dental or medical procedures. In this category, foods have a thick, gelatinous, or paste-like texture.

Examples of Semi-Solid and Pureed Foods

Mashed potatoes and gravy
Applesauce
Hummus
Smooth yogurt or kefir
Pudding and soft custard
Refined hot cereals like grits or farina
Blended casseroles or stews

A Comparison of Non-Solid Food Categories


Feature	Clear Liquids	Full Liquids	Semi-Solids/Purees
Consistency	Transparent and free of pulp or residue	All fluids and foods that become liquid at room temperature	Soft, mashed, and smooth, requiring minimal chewing
Digestibility	Very easy to digest	Relatively easy to digest	Requires more digestion than liquids, but still gentle
Typical Use	Pre-surgery/medical tests, post-surgery, or digestive problems	Transition diet after clear liquids, swallowing difficulties	Infant feeding, recovery from surgery, dysphagia
Examples	Broth, water, gelatin, apple juice	Strained cream soups, milk, ice cream, pudding	Mashed potatoes, hummus, applesauce, thick yogurt
Nutritional Density	Very low	Moderate; higher than clear liquids	Can be nutrient-dense depending on ingredients

Context Matters: Travel vs. Diet

Defining what is and is not a solid can depend entirely on the context. For medical professionals, the criteria are based on how the body digests the food. For example, ice cream is a full liquid because it melts inside the body, making it easy to process. However, the Transportation Security Administration (TSA) has a different set of rules for airline travel.

The TSA's 3-1-1 Rule for Liquids, Gels, and Aerosols

For air travel, the TSA operates under a different set of rules, where a substance's state at room temperature is the determining factor. The 3-1-1 rule for carry-on luggage means containers must be 3.4 ounces (100 ml) or less, and all must fit in one clear, resealable, quart-sized plastic bag. This rule includes many foods that are not considered solids in a culinary or medical sense.

Foods Classified as Non-Solids by the TSA

Yogurt
Pudding
Jams and jellies
Salsa
Peanut butter and other nut butters
Hummus
Mashed potatoes (if prepared with liquid)
Maple syrup
Soft cheese spreads
Canned items containing liquid, like canned tuna in water, must also follow the size limitations.

It is important to remember that for the TSA, if a food can be spread, squeezed, or poured, it is a non-solid. Always check the TSA website or their 'What Can I Bring?' tool before flying to avoid losing a favorite snack.

Conclusion

Defining what foods are not considered solids depends on the specific context, whether it is for a medically supervised diet or navigating airline travel regulations. Key categories include clear liquids, full liquids, and semi-solids, each with a unique role based on consistency and digestibility. While a medical diet focuses on how food is processed by the body, travel rules focus on a substance's physical state at room temperature. For anyone dealing with dietary restrictions or simply curious about food classifications, understanding these distinctions is an important and practical piece of knowledge. For more information on medical diets, one can consult reliable resources like the MedlinePlus Medical Encyclopedia.

Frequently Asked Questions

A clear liquid diet consists of transparent fluids like broth, water, and pulp-free juice, leaving no residue. A full liquid diet includes all items in a clear liquid diet plus milk, creamy soups, pudding, and foods that turn to liquid at room temperature, such as ice cream.

Applesauce is typically considered a semi-solid or pureed food. While not a true liquid, its mashed, smooth texture requires very little chewing, making it suitable for diets that restrict solids.

The TSA classifies peanut butter and similar foods like hummus and jams as gels or spreads, which fall under the 3-1-1 liquid rule for carry-on luggage. Their classification is based on whether an item can be spread, poured, or squeezed, not its culinary definition.

Canned food containing both solids and liquids is subject to the TSA's liquid regulations. Any liquids within the can must be 3.4 oz (100 ml) or less. Larger quantities must be placed in checked baggage.

In a medical dietary context, yes. Ice cream and gelatin are considered full liquids because they melt at room or body temperature. For travel purposes, they are also considered non-solids and subject to the 3-1-1 rule.

Practical non-solid foods include beverages like juices and milk, smooth desserts such as pudding and yogurt, and pureed items like soups and smoothies. Many baby foods are also examples of semi-solid purees.

A diet of non-solid foods may be necessary for individuals recovering from surgery, undergoing certain medical tests, experiencing difficulty swallowing (dysphagia), or during an infant's introduction to solid foods.