Macronutrients 101: The Dietitian’s Guide to Dietary Fat

Macronutrients (macros) are a common discussion point in the nutrition industry. But macros aren’t just a trend, as any balanced nutrition plan should factor in the quality and number of macros you consume. This article is part three of a three-part series that clarifies the conversation surrounding all three macros: proteins, carbohydrates and dietary fats.

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For several decades, grocery store aisles have been plagued with low fat and fat-free items. Because fat is higher in calories, it’s easy to assume that cutting fat is the best way to improve your weight and overall health. However, your body needs a certain level of body fat and a certain level of dietary fat to function. This still leaves the ominous question, will eating fat make me fat?
The idea that eating any amount of dietary fat will cause an increase in body fat is a myth. This is simply not how it works. Many factors play a role in our weight, including stress, physical activity and total caloric intake. Adding more good fat to your diet can actually protect your heart and improve your health!

Let’s explore further.

What is Dietary Fat?

While your body makes body fat as a means to store extra energy, body fat is different from dietary fat, or the fat found in the food you eat. Dietary fats, also known as lipids, is one of the three macronutrients that the body needs to function. Fats can be solid or liquid at room temperature. The solid ones are often called “fat” while liquids are commonly referred to as “oils.”
Dietary fats, at their basic level, are organic molecules comprised of carbon and hydrogen joined together in long chains by hydrocarbons. The arrangement of hydrogen on the fat determines how it performs in the body and how it can impact your health.

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Why Do I Need Dietary Fat?

Aside from adding flavor and texture to our food, consuming healthy fats is vital for great health. First, fat is an excellent source of energy. One gram of fat provides nine calories, which is more than double that of carbohydrates or protein.
Fat-soluble vitamins, such as vitamins A, D, E and K, rely on fat to absorb, transport and store them in the body. Fat-soluble vitamins help regulate blood pressure, heart rate, blood vessel constriction, blood clotting and nervous system function. Drastic limits on fat intake can quickly create a vitamin deficiency and impair these functions in the body.

A few fats, specifically omega-3 and omega-6 fatty acids, are considered essential because they cannot be made by the body and must be consumed through food. Essential fatty acids have many functions within the body that include improving immunity, cell signaling, mood and brain growth/health and decreasing inflammation. [1]

What are the Different Types of Dietary Fats?

Dietary fats are not created equal, and it’s important to understand the impact they have on your body. Dietary fats are found in several forms: unsaturated, saturated and trans fats. Here’s a breakdown of each type of fat, their functions and food sources.

As well as food sources of each:
Unsaturated fats are healthy fats that should make up the largest percentage of people’s fat intake. These fats are known to be heart-protective as they may reduce the risk of heart disease and lower cholesterol levels.
Unsaturated fats are split into two categories:

  • monounsaturated fat
  • polyunsaturated fat

Monounsaturated fats contain one (mono) bond that is not saturated with hydrogen. Studies show that eating foods rich in monounsaturated fats improves blood cholesterol levels by lowering total cholesterol and LDL cholesterol.
The most abundant sources of monounsaturated fats include:

  • Nuts, such as peanuts, walnuts and almonds
  • Avocados
  • Olive oil

Polyunsaturated fats contain multiple (poly) carbon bonds that are not saturated with hydrogen. Omega-3 fatty acids are the most known and researched polyunsaturated fat. Omega-3 fatty acids are essential fats that the body can’t make and must get from food. Research shows that omega-3s are heart-protective. Increasing your intake of omega-3s can help lower your blood pressure and heart rate, ease inflammation and lower triglycerides at higher intakes.
The most abundant sources of polyunsaturated fat include: [2]

    • Flax seeds
    • Chia seeds
    • Salmon
    • Walnuts
    • Avocados
    • Shellfish (oysters)


Saturated fats are tightly packed fats with all carbon bonds that are saturated with hydrogen. Saturated fats are often called ‘bad fats’ due to their association with an increased risk of high cholesterol. However, research is now showing that the saturated fats found in grass-fed beef and plant-derived sources may have a neutral effect on cholesterol levels. [3]
Common animal-based sources of saturated fats include:

  • Dairy foods, such as butter, cream, ghee, milk and cheese
  • Meat, such as red meat, some pork and chicken

Common plant-derived sources of saturated fats include:

  • Palm oil
  • Cooking margarine
  • Coconut oil, milk or cream

Trans fats can be naturally-occurring or from an artificial source. Naturally-occurring trans fats are produced in the gut bacteria of some animals. Fo

How Much Dietary Fat Should I Consume Per Day?

There is ongoing research as to the potential health benefits of a higher fat diet. The current USDA Dietary Guidelines for Americans 2020 recommends that 20 to 35% of your daily caloric intake come from fats. For people on a 2,000-calorie diet, this translates to 44 to 78 grams of fat per day. [5]

However, fats are not created equal. As such, the USDA recommends that saturated fats should be limited to less than 10% of calories per day and be replaced with unsaturated fats. They also recommend that people mitigate their daily trans fat intake as much as possible.

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What is Ketosis and How Does it Relate to Dietary Fat?

Ketosis is a metabolic state where your liver produces raised levels of “ketones” through the digestion of fat. Typically, glucose is your body and brain’s primary fuel source, but it can be replaced by ketones in the absence of glucose. When in ketosis, your body relies on fat as a fuel source.

A typical breakdown of macros for people on the keto diet is 70% fat, 20% protein and less than 10% of calories from carbohydrates. However, the ketogenic diet is not for everyone. Consult a doctor to make sure the ketogenic diet is right for you before changing your eating habits.



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written by

James Gardikas

James Gardikas

Contributing Writer