Fat has several meanings, depending on the context. This article discusses the different definitions of fat, making it clearer for you next time you read about fat, oil, lipids, triglycerides or adipose tissue.
Words like “fat” and “lipid” are used interchangeably by many sources, including some official (government or scientific) sources. This makes it confusing for the readers to understand the topic thoroughly.
There is one common meaning of the term fat among all of the definitions – it is a non-water soluble substance. The rest depends on the context in which it is being used.
The following are examples of some common meanings of the word fat: (1):
- Dietary fat
Dietary fats, also called food fats, refer to the edible components of animals and plants that are non-water soluble. They should ideally be called dietary lipids, since in reality they are composed of a large variety of lipids (to learn about the difference between fats and lipids, read here).
Most dietary fats are composed of triglycerides (about 95%), but they also have other lipids, such as free fatty acids, mono-glycerides, di-glycerides, sterols, fat-soluble vitamins, pigments, tocopherols, tocotrienols, fatty alcohols and waxes.
In a culinary sense, dietary fats include:
– solid in room temperature fats
– liquid in room temperature oils.
Examples of dietary fats are: vegetable oil, fish oil, lard, shortenings, margarine, ghee, butter, fatty pieces of meat and fish, fatty components in eggs, nuts and seeds. (To find out why we need fats in our diet click here)
- Fat as opposed to oil – The melting point differentiation
Fat refers to a group of lipids that are solid at room temperature (unlike oils, which are liquid). What defines fat are its melting point properties.
From the melting point perspective, fats include food components, such as the fatty offcuts from meat and various spreads (dairy butter, margarine, shortening or nut butter). It doesn’t include oils, such as vegetable oils or fish oils.
Coconut oil/butter has a melting point around room temperature. This places it between fats and oils.
The melting point depends on various factors, but mainly on the level of saturation (e.g. saturated vs unsaturated) and the length of the hydrocarbon chains (short vs. long).
Saturated fatty acids and long fatty acids have higher melting points. (read more..)
- Fat as lipid
Fat and lipid are interchangeably used in the scientific context, even by official sources. This adds to the confusion, since there is no consistency of the nomenclature.
Many sources instead of referring to lipids as lipids, call them fats.
Lipids are a broad category of non-water soluble substances. They include a wide range of edible and non-edible components, and fats are just one of them.
Fats have several meanings, as presented in this article and, depending on the context, can indicate a triglyceride molecule, solid in room temperature lipids, body fats or dietary fats.
- Fat as a triglyceride molecule – the fat molecule
Some scientific sources use the term fat or fat molecule to refer specifically to a triglyceride molecule. (read more..)
The triglyceride molecule belongs to a subcategory of lipids called glycerides. It is composed of a glycerol backbone and three free fatty acids (another subcategory of lipids).
Mono and di-glycerides (belonging to the same subcategory of lipids) are usually not considered to be fats, since they have they have emulsifying properties.
- Body fat
Fat also refers to body fat. It includes the lipids that accumulate in the body fatty tissue and a wide range of lipids circulating in the body.
Fat in our body has many important functions, such as the storage and production of energy, cushioning the internal organs against external shock and keeping the core temperature at a normal level.
It is also used in the production of hormones, protection of nerves, for better skin and hair health and as a transport and storage mechanism of important fat soluble vitamins. (read more..)
However, if an excess of fat is accumulated, especially in the abdominal area (abdominal obesity), its’ negative health effects outweigh its’ benefits. It can lead to insulin resistance and increase the risk of developing cardiovascular diseases.