Top Line

This article will serve as a brief overview of why fat is an essential part of our diet.

Why it matters

Fat supports many functions within the body, including supporting cell structure, protecting organs, insulation, absorbing toxins, neuroprotective qualities and much more.

Key takeaways

• Fats, also known as lipids, come in many forms. The most notable forms pertaining to this article are; triacylglycerols (formerly known as triglycerides), sterols (cholesterols), and lipoproteins.
• Triacylglycerols represent most of the stored energy within our body fat and make up approximately 95% of our dietary fat.
• How much fat you should consume on a daily basis depends on many factors like your genetics and overall goals.

Three reasons fat is essential

Reason #1

Body fat stores energy, nutrients, and toxins, provides protection to our internal organs, and helps regulate our body temperature by insulating against heat loss.

Reason #2

The cholesterol we consume in our diets helps form the plasma membranes of our cells. It also acts as a precursor for many important steroids in the body, including the bile acids; steroid sex hormones such as estrogens, androgens, and progesterone; the adrenocortical hormones; and vitamin D.

Reason #3

Cholesterol is important for cognitive function as your brain makes up only two percent of your body weight but contains 25% of your body’s cholesterol. Moreover, that 25% of cholesterol helps form our myelin sheath which coat the outer parts of the neurons in our brains. Neurons are special structures that you can think of as highway roads carrying signals within us.

In other words, neurons are the roads that make up the highways and myelin sheath are the guardrails on either side of the road. Thus, in our brain, for us to be able to recall how to do everyday tasks, memories, and communicate externally and internally, our myelin sheath need to be fully intact or those signals will get disrupted or blocked.

As you might have guessed, this is a primary factor in people with Multiple Sclerosis and Alzheimer’s disease. As a result, a diet deficient in fat is linked to a decline in cognitive function and memory. In addition to being a potential risk factor for developing Alzheimer’s.

Now wait, I thought cholesterol is bad for you?

First, the lipoproteins mentioned earlier constitute a mix of lipids and proteins that transport lipids via our blood. The main lipoproteins that allow this are the two cholesterols, low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

It is important to understand that cholesterol is not inherently good or bad. In general, doctors consider it as a good thing to have low levels of circulating LDL and high levels of HDL. Therefore, LDL is considered the “bad” cholesterol and HDL is considered the “good” cholesterol. Indeed, it is good for your overall health to have lower LDL than HDL. Thus, it is more about the ratio of LDL:HDL. Although the ratio between HDL and triacylglycerols is becoming a better indicator of disease but, that is for another discussion.

Functions of LDL and HDL

Both LDL and HDL have important functions within the body. In short, the liver also stores triacylglycerols but in a limited capacity. Consequently, LDL is called upon to transport the triacylglycerols throughout the body to be stored and utilized for energy.

I will use our aforementioned highway analogy to help explain HDLs function. On this highway, HDL are like recycling trucks. The HDL go out and scavenge any unused fat and bring it back to the liver to be converted into bile and eventually excreted. The LDL are more like small trucks transporting the triacylglycerols from the liver to our cells throughout the body.

The LDL are smaller and therefore, cannot carry as many triacylglycerols. So, these small trucks tend to overflow and leave stuff behind on the road. This usually happens when there is a high amount of triacylglycerols the liver cannot store and is therefore circulating in the blood.

These left behind particles is what contributes to plaque build up in our arteries and potentially leads to cardiovascular disease. That is to say, if our HDL recycling trucks are not able to pick them up and shuttle them back to the liver. There are many reasons as to why this process falls apart, one of them being not eating enough healthy fats!

The final word

Alright, time to reign it back in. Long story short, the fat we eat supports many essential functions within our body. Simply put, if we do not eat enough healthy fats our body will suffer the consequences. As a result, unnecessary health issues may arise. Consuming healthy fats will support a better LDL:HDL ratio and a better HDL:Triacylglycerol ratio. This in turn supports overall health making dietary fat an essential part of our diets.

However, consuming healthy fats is only one part of the puzzle as the body needs to be able to properly store and utilize that fat. There are several mechanisms at play when it comes to storing and burning fat. Simply eating healthy fats is not enough to keep those mechanisms functioning properly. As you might have already guessed, exercise plays a huge role in maintaining and up-regulating those mechanisms. Additionally, the amount and types of carbohydrates also play a role in how your body will store and utilize fats.

Jon Esposito MA, CSCS, CISSN, USAW