What are fats and oils in foods called? The complete guide

December 22, 2025 •

4 min read

Did you know that fat provides 9 calories per gram, making it the most energy-dense macronutrient? So, what are fats and oils in foods called on a technical level, and why does understanding this terminology matter for your health and diet?

Quick Summary

Fats and oils are scientifically referred to as lipids and, in a nutritional context, as triglycerides, based on their molecular structure and physical properties.

Key Points

Lipids vs. Triglycerides: The general class of fats and oils is called lipids, while the specific type found in food is known as triglycerides.
Fat vs. Oil: The difference lies in their state at room temperature; fats are solid due to saturated fatty acids, while oils are liquid due to unsaturated fatty acids.
Saturated Fats: These are solid at room temperature and typically come from animal products and some tropical oils, with high intake linked to elevated LDL cholesterol.
Unsaturated Fats: These are liquid at room temperature and are generally considered healthy, including monounsaturated (e.g., olive oil) and polyunsaturated (e.g., omega-3s) varieties from plant and fish sources.
Trans Fats: Often artificially created, these are the unhealthiest type of fat, raising LDL cholesterol while lowering beneficial HDL cholesterol.
Essential Functions: Fats are vital for storing energy, building cell membranes, and helping the body absorb fat-soluble vitamins.

The Scientific Name for Fats and Oils

On a technical and scientific level, the broad category that encompasses fats and oils is known as lipids. This large group of biomolecules is defined by its insolubility in water and solubility in organic solvents. Lipids serve a number of critical functions in the body, including energy storage, cell structure, and the transport of fat-soluble vitamins like A, D, E, and K.

More specifically, the type of lipid that makes up most of the fats and oils we consume in our diet is called a triglyceride, or triacylglycerol. Triglycerides are composed of a glycerol molecule bonded to three fatty acid chains. The structure of these fatty acid chains determines whether the substance is a fat or an oil and has a significant impact on its physical properties and nutritional profile.

The Key Difference: Fats vs. Oils

The most straightforward distinction between fats and oils is their physical state at room temperature. Fats are solid, while oils are liquid. This difference is primarily due to the chemical makeup of their fatty acid chains.

Fats, such as butter and lard, are rich in saturated fatty acids, which lack double bonds in their carbon chains. The straight, single-bonded chains allow the molecules to pack tightly together, resulting in a solid form at room temperature. In contrast, oils like olive and canola oil contain a high proportion of unsaturated fatty acids, which have one or more double bonds in their carbon chains. These double bonds introduce 'kinks' or bends in the chain, preventing tight packing and causing the substance to remain liquid.

Types of Fatty Acids in Food

The fatty acid composition of triglycerides is what makes each fat and oil unique. The four main types of dietary fats have different structures and effects on the body.

Saturated Fats: As mentioned, these contain no double bonds and are solid at room temperature. They are commonly found in animal products and some tropical oils. Foods like red meat, butter, cheese, and coconut oil are high in saturated fat. High consumption is often linked to increased LDL ('bad') cholesterol.
Monounsaturated Fats (MUFAs): These have one double bond in their fatty acid chain and are typically liquid at room temperature. They are often found in plant-based sources and are considered heart-healthy. Examples include olive oil, avocados, nuts, and seeds.
Polyunsaturated Fats (PUFAs): Featuring two or more double bonds, these are also liquid at room temperature. This category includes essential omega-3 and omega-6 fatty acids, which the body cannot produce on its own. Sources include fatty fish, walnuts, and sunflower oil.
Trans Fats: These are created through a process called hydrogenation, which turns liquid oils into solid fats to extend shelf life. While naturally occurring in small amounts in some animal products, most trans fats are artificial and are widely considered the most harmful type of fat. They raise LDL cholesterol and lower HDL ('good') cholesterol.

The Role of Fats and Oils in Cooking and Health

Beyond their chemical classification, fats and oils play distinct roles in both cooking and human health. Their unique properties dictate how we use them in the kitchen and how our bodies process them.

Cooking Applications: The smoke point, flavor, and texture provided by fats and oils are all determined by their molecular structure. For example, solid saturated fats like butter are ideal for baking, while liquid unsaturated oils like olive oil are perfect for sautéing or dressing salads.
Flavor and Satiety: Fats carry flavor molecules and provide a sense of richness and satisfaction, or satiety, to meals.
Essential Nutrients: Unsaturated fats, particularly omega-3s and omega-6s, are crucial for cell growth and overall health.

Comparison of Different Types of Fats


Feature	Saturated Fats	Monounsaturated Fats	Polyunsaturated Fats	Trans Fats
State at Room Temp.	Solid	Liquid	Liquid	Solid
Fatty Acid Bonds	Single bonds only	One double bond	Two or more double bonds	Artificial trans double bonds
Primary Sources	Animal products, tropical oils	Plant-based oils, nuts, seeds	Fatty fish, flaxseed, walnuts	Processed foods, fried foods
Heart Health Impact	Can increase bad (LDL) cholesterol	Can lower bad (LDL) cholesterol	Can lower bad (LDL) cholesterol	Raises bad (LDL) and lowers good (HDL) cholesterol
Dietary Recommendation	Limit intake	Recommended for heart health	Recommended for heart health	Avoid whenever possible

Conclusion

In summary, the scientific answer to the question "What are fats and oils in foods called?" is a layered one. The overarching term is lipids, while the more specific name for dietary fats and oils is triglycerides. The specific type of fatty acid chains within these triglycerides determines their properties, categorizing them as saturated, unsaturated, or trans fats. Understanding this classification is crucial for making informed dietary choices that promote heart health and overall wellness, prioritizing unsaturated fats over saturated and avoiding artificial trans fats whenever possible. For more information on making healthy fat choices, read the recommendations from the American Heart Association on Dietary Fats.

Frequently Asked Questions

The primary scientific term that encompasses all fats and oils is 'lipids.' This is a broad category of organic compounds that are insoluble in water.

Most of the fats and oils we consume are specifically called 'triglycerides.' A triglyceride molecule consists of a glycerol backbone attached to three fatty acid chains.

The main factor is its state at room temperature. Lipids that are solid are called fats, and those that are liquid are called oils. This is determined by the saturation level of their fatty acid chains.

Not all fats and oils are bad. While saturated and trans fats can have negative health effects, monounsaturated and polyunsaturated fats are essential for good health and heart function.

Common saturated fats include butter, lard, red meat, cheese, and tropical oils like coconut oil and palm oil.

You can find healthy monounsaturated and polyunsaturated fats in sources like olive oil, avocado, nuts, seeds, and fatty fish such as salmon.

The essential fatty acids are a type of polyunsaturated fat that the body cannot produce itself. These include omega-3s and omega-6s, found in foods like fatty fish and walnuts.