Nutrition Science and Everyday Application - beta v 0.1

The Functions of Fats
Fats serve useful functions in both the body and the diet. In the body, fat functions as an
important depot for energy storage, offers insulation and protection, and plays important
roles in regulating and signaling. Large amounts of dietary fat are not required to meet these
functions, because most fat molecules can be synthesized by the body from other organic
molecules like carbohydrate and protein (with the exception of two essential fatty acids).
However, fat also plays unique roles in the diet, including increasing the absorption of fatsoluble
vitamins and contributing to the flavor and satisfaction of food. Let’s take a closer
look at each of these functions of fats in the body and in the diet.
THE FUNCTIONS OF FATS IN THE BODY
Storing Energy
The excess energy from the food we eat is incorporated into adipose tissue, or fatty tissue.
Most of the energy required by the human body is provided by carbohydrates and lipids.
As discussed in the Carbohydrates unit, glucose is stored in the body as glycogen. While
glycogen provides a ready source of energy, it is quite bulky with heavy water content, so
the body cannot store much of it for long. Fats, on the other hand, can serve as a larger
and more long-term energy reserve. Fats pack together tightly without water and store far
greater amounts of energy in a reduced space. A fat gram is densely concentrated with
energy, containing more than double the amount of energy as a gram of carbohydrate.
We draw on the energy stored in fat to help meet our basic energy needs when we’re
at rest and to fuel our muscles for movement throughout the day, from walking to class,
playing with our kids, dancing through dinner prep, or powering through a shift at work.
Historically, when humans relied on hunting and gathering wild foods or on the success
of agricultural crops, having the ability to store energy as fat was vital to survival through
lean times. Hunger remains a problem for people around the world, and being able to store
energy when times are good can help them endure a period of food insecurity. In other
cases, the energy stored in adipose tissue might allow a person to weather a long illness.
Unlike other body cells that can store fat in limited supplies, fat cells are specialized for
fat storage and are able to expand almost indefinitely in size. An overabundance of adipose
tissue can be detrimental to your health not only from mechanical stress on the body due
to excess weight, but also from hormonal and metabolic changes. Obesity can increase the
risk for many diseases, including type 2 diabetes, heart disease, stroke, kidney disease, and
certain types of cancer. It can also interfere with reproduction, cognitive function, and mood.
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