Fat. It’s what makes up your brain, cushions your organs and helps insulate your body. It's also a macronutrient. Macronutrients — protein, carbohydrates, fat and water —are substances required in relatively large amounts for survival. 

Although it's common to think fat is bad for you, and that eating a low-fat diet is best for your body, it's actually quite the opposite. Fat has over 100 different roles in the body — 100! From carrying vitamins throughout your body to regulating blood pressure, ovulation and hormone synthesis, we all need fats. Here's why.

Fat Increases Satiety

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Denise Uy

Satiety —  the feeling after you eat a big, delicious meal — is important for your body to balance calories. Often times when you don't feel satiated it's because you either didn’t eat enough, or more commonly, are lacking a macronutrient. Many people avoid fats for various reasons, but low-carb, high-fat diets are actually shown to improve satiety levels more than high-carb, low-fat diets. Fat slows the absorption of food into the small intestine, giving the feeling of being satisfied and ending the search for more food.

EFAs to the Rescue

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Amy Yi

Essential Fatty Acids (EFAs) are fats that the body cannot synthesize on it's own, so we have to get them from food. The two fatty acids bodies cannot produce are alpha-linolenic acid and linoleic acid, commonly referred to as omega-3 and omega-6 fatty acids. Both of these fatty acids are needed for growth and repair, but can also be used to make other fatty acids. Omega-3 fatty acids are found in foods like wild-caught fish, chia seeds, flax seeds and walnuts. Omega-6 fatty acids are found in oils such corn, safflower, sunflower, grapeseed, soy, peanut and vegetable, and in mayonnaise and many salad dressings. DHA, an omega-3 fatty acid, can help with memory, speaking ability and motor skills, as well as reduce conditions such as depression, bipolar disorder and ADHD.

Brain and Heart Health, Please!

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Jessica Kelly

The human brain is nearly 60 percent fat. Keeping this in mind, it’s clear that it's necessary to include dietary fat in your daily diet for your brain to operate and perform its best. When dietary intake of fat is low, especially from EFAs, it can lead to impaired performance. In fact, clinical observation studies have related an imbalance in dietary intake of fatty acids to impaired brain performance and diseases.

There is a common misconception that saturated fat is bad for you. However, recent studies have come out emphasizing the importance of consumption of saturated fat (in moderation). Saturated fat is actually one of the main components of brain cells, and is therefore necessary for healthy brain function. In one study, it was found that people who ate more saturated fat reduced their risk for developing dementia by 36 percent. Saturated fat also provides benefits for the liver and immune system, and helps maintain proper hormone balance.

Fat also is functional for the heart. According to Harvard Health, omega-3 fatty acids may help prevent and even treat heart disease and stroke. Omega-6 fatty acids have also been linked to protection against heart disease. Polyunsaturated fats may help prevent lethal heart rhythms from arising. Lethal heart rhythms, if not caught early enough, can lead to cardiac arrest. Harvard's long-running study shows a correlation between high consumption of nuts — a good source of monounsaturated fats— and low incidence of heart disease. Yes, correlation is not causation, but its hard to ignore the relation of the data in this study. Additionally, saturated fats have been shown, in several studies, to reverse cardiovascular risk factors.

Fat as Fuel

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Denise Uy

Contrary to popular belief, fat is the primary fuel source for your body at rest and during prolonged exercise (such as walking for an hour or running a marathon). The only exception to this is the central nervous system and red blood cells, which primarily get their energy from carbohydrates.

Even doing a low-energy, like sitting at a desk, requires "fuel." Fat supplies 50 to 90 percent of your required energy for just basic functioning. Low-fat diet can cut off this essential energy needed for your body, leaving you feeling sluggish.

How Much You Should Be Eating

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Torey Walsh

A diet where less than 20 percent of calories eaten are fat is considered to be a diet too low in fat. For example, if on a given day one person eats 2,000 calories, 400 of those calories need to come from fat. One gram of fat contributes 9 calories, which means a person eating a 2,000 calorie diet needs to eat a minimum of 45 grams of fat per day. 

That may seem like a large amount of fat, but it is easy to reach this recommended amount with some thought. One tablespoon of olive oil contains 14 grams of fat; One avocado provides 29 grams of fat; Three ounces of salmon has 11 grams of fat. It can add up quickly.

The recommended amount of fat is 20 to 35 percent of total calorie intake. This means  someone eating 2,000 calories in a given day should be eating 45 to75 grams of fat, or 400 to 700 of calories from fat. A deficiency in fats, specifically essential fatty acids can lead to slow growth, delayed healing of wounds and infections, flaky or itchy skin, brittle nails, and decreased levels of HDL levels: a type of cholesterol that removes the harmful cholesterol from the body.

However, everyone’s body is different and some may feel better  eating a bit on the lower end or higher end of this range. Do whatever feels best to you!

Thank Fat For That

Don't fear fat, face it and embrace it! Fat is necessary for human survival — and tasty too. This macronutrient benefits essential organs like the heart, brain, kidney and liver, and is in every single cell in the human body.

So, the next time you sit down to eat, consider adding fish, olive oil, salad dressing or a handful of nuts to your meal — and another avocado never hurts either! And remember, at the end of the day, if your body is performing well, you can probably thank fat for that.