Dietary Fat: What Is It?

Despite what people may say, fat is a necessary nutrient for the body’s health and well-being. 

Doctors recommend people eat the right amount and type of dietary fat to maintain good health.

On the ketogenic diet, it’s required to have a specific amount of fat in your daily diet. 

This article will break down what fat is, its function in the body, the different fat types in food, and how much you should eat to stick to your diet.

Fats Function In The Body

Fat is one of the three macronutrients. Macronutrients are the nutrients, such as protein, carbohydrates, and fat, that our bodies need for growth, development, and function. 

The amount of energy that a food contains is determined by the number of its calories.

The number of calories in food is measured in kilocalories (kcal). One kcal equals one calorie.

The body converts these caloric foods into energy, which it can use for walking, running, or playing sports.

Fat has a total of 9 calories per gram, compared to 4 for each gram of carbohydrate or protein. Fat will take up more stomach space and is digested more slowly than carbohydrates and protein.

The main function of fat in our bodies is to serve as energy storage, and it also helps regulate hormones. 

Dietary fat is a type of lipid that is essential for life. It acts as a medicine in the body for the production of hormones and cell membrane components.

After about 20 minutes of exercise, the body starts using stored fat for energy. (1

Another function of fats is they are needed for the body to absorb fat-soluble vitamins, like A, D, E, and K. Dietary fat plays a role in keeping our skin and hair healthy, insulates the body, protecting organs, and filling fat cells.

Your body can’t survive without essential fatty acids. It can’t produce essential fatty acids independently, so the body relies on them from outside sources through dietary fat. 

Essential fatty acids are a kind of fat that you need for good health. They come in two categories: Omega-3 and omega-6 fatty acids. 

Both are considered important for maintaining optimal health, but Omega-6s may have more of an inflammatory effect while Omega-3s reduce inflammation.

Good And Bad Fat Types

There are different kinds of dietary fat, and they are not all created equal. There is good fat and bad fat, and each type can be found in the food we eat. 

Unsaturated fats are much healthier for our bodies to consume than saturated fats. It has been observed that saturated fats can lead to plaque build-up in the arteries, while unsaturated fats do not.

Let’s look at the breakdown of saturated and unsaturated fats and how healthy (or not) each is.

Saturated Fat

Saturated fat can be found in animal meat and dairy products. 

It has long been associated with heart disease in the Western diet, and recent research suggests saturated fat hurts weight loss.

When at room temperature, saturated fats are solid like butter and cheese.

Palm, palm kernel, and coconut oil are also high in saturated fat. This is why it’s easy to hide if you don’t know what to look for on nutrition labels.

Saturated fat has also been linked to high levels of cholesterol, water retention, and cardiovascular disease. 

The American Heart Association (AHA) recommends a diet with less than 6% of calories from saturated fat. (2)

Trans Fat

Trans fat also goes by the name hydrogenated oil. Companies use it to prolong shelf life, create a more even consistency in texture, and give food a nicer flavor.

What makes trans fat different from other oils is hydrogenation, which chemically changes liquid vegetable oils into solids.

The impact of trans fat on your health has been highly debated. 

While some studies have associated it with higher rates of liver and coronary heart disease, other studies have found that trans fats are not a significant contributor to these types as once thought.

Trans fat can be found in many different food items such as cakes and pastries, chips, doughnuts, french fries, and most fried foods. 

It is also found in most prepared foods and partially hydrogenated oils due to not having to change the oil that frequently.

Due to the mixed reviews on trans fat, the FDA is considering removing it from all food labels, but health organizations are asking for a full ban on trans fat. 

This decision has been preliminarily approved by the FDA and will be implemented in the next six to ten years. The United States is not legally bound by this decision, but many countries are doing so. 

We can expect that within a few years, we will not see trans fat on food labels any longer.

While more studies need to be done on trans fat, it’s best to try and avoid it.


Triglycerides are a kind of fat in our bloodstream. They are the most common form of fat found in the human body, and they’re made up of three fatty acids attached to a molecule of glycerol.

The body stores excess calories as triglycerides if it doesn’t need them right away. Triglycerides get stored in fat cells, and then hormones release them during periods of low energy consumption. (3)

These are the standard health guidelines when looking at triglyceride levels in the body: 

  • Less than 150 milligrams per deciliter (mg/dL) is in the normal range.
  • 150 – 199 mg/dL (1.8 to 2.2 mmol/L) is borderline high.
  • 200 – 499 mg/dL (2.3 to 5.6 mmol/L) is considered high.
  • 500 mg/dL and above (5.7 mmol/L and above) is extremely high.

You can check your triglyceride levels, which indicate risk for heart disease and stroke, by doing a blood test called a lipid panel. 

Your doctor will measure your total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. Total cholesterol measures the total amount of fat in the blood.

Monounsaturated Fat

Monounsaturated fats are the fats that consist mainly of a single molecule of unsaturated fat with one double-bond.

These fats occur naturally in foods like olive oil, avocados, and nuts. They are considered healthy fats because they have fewer negative or potentially harmful effects than saturated or trans-fats that contain more than one double bond between carbons.

Monounsaturated fat helps to lower the levels of bad cholesterol. It is beneficial because it does not raise the bad cholesterol that can lead to cardiovascular disease.

While on the ketogenic diet, monounsaturated fat is some of the best healthy fat you can consume. 

Although there is no recommended daily amount for monounsaturated fat, most of your daily fat calories should come from foods high in unsaturated fat.

Polyunsaturated Fat

Polyunsaturated fat is a fat that has more than one double-bond in its structure. 

In other words, polyunsaturated fat has a relative proportion of unsaturated bonds to saturated bonds greater than one. Omega-3 and Omega-6 fatty acids are known as two types of polyunsaturated fats.

Polyunsaturated fat is found in fatty cold-water fish like salmon, mackerel, herring, and trout. It is also found in flaxseed oil and other nuts and seeds.

Polyunsaturated fat has been shown to positively impact cholesterol levels, reduce the risk of cardiovascular disease, and increase weight loss among dieters.

Like monounsaturated fat, there are no exact guidelines for how much to consume each day, but if you’re following the ketogenic diet, most of your diet should consist of foods high in unsaturated fat.

Omega-3 Fatty Acids

Omega-3 fatty acids are polyunsaturated fatty acids that contain two carbon chain lengths of 18 carbons and three double bonds. 

There are three specific omega-3s:

  • Alpha-linolenic acid (ALA)
  • Eicosapentaenoic acid (EPA)
  • Docosahexaenoic acid (DHA). 

Omega 3s have been extensively studied for their roles in reducing risk for coronary heart disease, stroke, hypertension, arthritis pain, cancer progression, Alzheimer’s Disease, and other causes of cognitive decline.

Omega-3 fatty acids are also important anti-inflammatories. They have the opposite effect of cyclooxygenase-2 (COX2). 

Omega-3s prevent COX2 from producing pro-inflammatory prostaglandins. They reduce inflammation and protect LDL from oxidation.

Foods that contain high levels of Omega-3 fatty acids are considered heart-healthy foods by the American Heart Association. 

Fats found in vegetable oils, oily fish, and nuts are high in Omega-3 fatty acids. Some other sources of Omega-3 fatty acids include eggs, beef, pork, poultry, and soybean oil.

These kinds of food sources are going to be your main staple on keto. 

Omega-6 Fatty Acids

Omega-6 fatty acids are polyunsaturated fatty acids with the shortest carbon chain and are found in many different foods, such as nuts, seeds, and vegetable oils. 

These fatty acids are necessary for normal growth in hair and nails, overall bone development, and reproduction.

The optimal omega-6 fatty acid intake is unknown, but evidence suggests that it may be higher than the average American diet. 

The American diet has an Omega 6 to Omega 3 ratio of 10-20:1 or higher. 

This ratio can be reduced by lowering the intake of sources of Omega-6 fatty acids found in vegetable oils and animal fat and increasing consumption of fish products, which are a rich source of Omega 3 fatty acids, as stated earlier.

How Many Calories Should Come From Fat On The Ketogenic Diet?

A diet high in dietary fat is the pillar of a ketogenic lifestyle. 

By consuming a diet high in fat, you then restrict your carbohydrate intake to very low levels, which allows your body to enter into ketosis.

The process of ketosis is the production and accumulation of ketone bodies in the liver. When your body enters this state, it begins to burn fat for energy.

Eating a diet that’s high in fat and low in carbohydrates, like the ketogenic diet, can have dramatic effects on weight loss, but how much fat do you need to consume on the diet?

Not consuming enough dietary fat is a common ketogenic diet mistake and one that you shouldn’t make.

On the ketogenic diet, your macro breakdown will look roughly like this:

  • 5% of your calories will come from carbs
  • 20-25% of your calories will come from protein
  • 70-75% of your calories will come from fats

Keto is a diet that can be followed for life to stay fit.

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