Back to Basics: Fat
What are fats?
Dietary fats (fat) are one of the three macronutrients that make up the bulk of our diets (alongside protein and carbohydrates) and are essential to a healthy diet. Fats usually enter our diet through consuming animal fats or in butters and oils used in a wide variety of food.
There are 9 calories in every 1 gram of fat, regardless of what type of fat it is. Fats are more energy-dense than carbohydrates and protein, which provide four calories per gram.
There is a general recommendation for 30% of your daily calories to come from healthy fats.
Many of us grew up in an era when dietary fat was considered “bad” and unhealthy and it was believed to be the main cause of weight gain. During this time the fat in processed foods was often replaced with sugar, and many of us were eating extremely high carbohydrate, low fat diets, which many experts believe played a role in the obesity-epidemic still present today.
Fortunately, the trend of the low-fat diet has all but vanished, and we now have a better understanding on why dietary fat is an important part of a well-rounded, healthy diet. In fact, many people see success on very high fat diets such as Keto or Atkins for weight loss and other metabolic reasons.
Why are fats important for a healthy diet?
Like carbohydrates and protein, fats play an essential role in many basic functions in the body.
The main 3 functions are:
Structural- fat is a source of essential fatty acids, which the body cannot make itself. Triglycerides, cholesterol and other essential fatty acids store energy, insulate us and protect our vital organs. They act as messengers, helping proteins do their jobs. They also start chemical reactions that help control growth, immune function, reproduction and other aspects of basic metabolism.
Nutrient absorption-Fat helps the body absorb vitamin A, vitamin D and vitamin E. These vitamins are fat-soluble, which means they can only be absorbed with the help of fats.
Energy source and regulation-Along with carbohydrates and protein, fats are a source of energy in the diet. Fat is the most concentrated source of energy providing 9 calories per gram (more than double the energy found in carbohydrates and protein). The cycle of making, breaking, storing and mobilizing fats is at the core of how humans and all animals regulate their energy. An imbalance in any step can result in disease, including heart disease and diabetes
Types of Fats:
Fat is an important part of a healthy diet, but some types of fats are better for us than others.
There are 2 main types of dietary fats to consider:
Saturated-This is the so-called "bad" fat (up for debate...) and is primarily found in animal products like beef, pork, and high-fat dairy foods, like butter, margarine, cream, and cheese. High amounts of saturated fat also are found in many fast, processed, and baked foods like pizza, desserts, hamburgers, and cookies and pastries. These fats tend to more "solid" (think butter or lard) than healthier fats.
Unsaturated- This is the “healthy” fats, and there are two types: monounsaturated and polyunsaturated.
Monounsaturated fats are found in avocados and peanut butter; nuts like almonds, hazelnuts, cashews, and pecans; and seeds, such as pumpkin, sesame, and sunflower seeds. It is also in plant oils, such as olive, peanut, safflower, sesame, and canola oils.
Polyunsaturated fats include omega-3 fatty acids and omega-6 fatty acids. Polyunsaturated fats are found in plant-based oils like soybean, corn, and safflower oils, and they're abundant in walnuts, flaxseeds, sunflower seeds, and fish like salmon, mackerel, herring, tuna, and trout.
The main health issue with dietary fats is how they may influence cholesterol levels. Consuming high amounts of saturated fat produces more LDL (bad) cholesterol, which can form plaque in the arteries and increase your risk of cardiovascular disease and stroke.
Many processed and fast foods made with saturated fat also contain high amounts of calories, which can lead to weight gain and further raise your heart disease risk.
In comparison, the unsaturated fats help to raise HDL (good) cholesterol levels. HDL picks up excess LDL in the blood and moves it to the liver, where it is broken down and discarded
…But what about trans fats?
Trans fats are often formed through an industrial process that adds hydrogen to vegetable oil, which causes the oil to become solid at room temperature. Trans fats also exist naturally in some meat and dairy.
Trans fat is considered the most unhealthy type fat to eat. Unlike unsaturated fats, trans fats — also called trans-fatty acids —simultaneously lower your protective HDL cholesterol while raising the risky LDL cholesterol.
Fortunately, trans fats have all but been removed from the American diet- in 2019 the U.S. Food and Drug Administration (FDA) has prohibited food manufacturers from adding artificial trans fats to foods and beverages. Several countries and several cities in the United States have limited or banned the use of trans fats.
However, because added trans fats in foods allow for such a long shelf life there may still be items in the grocery store that contain trans fats. Trans fat content of foods can be found on a separate line immediately beneath the saturated fat on a nutrition label.
In response to the health concerns around trans fats, the WHO launched a global initiative called REPLACE, which demands restaurants and food manufacturers to eliminate artificial trans fats, in the form of partially hydrogenated oils, from the world food supply by 2023.
The takeaway:
Fats are an essential part of a healthy diet, as they play an essential role in many basic functions in the body. Unsaturated fats are considered healthier than saturated fars as they help raise HDL (good) cholesterol. There is conflicting research on the dangers of saturated fats in the body, especially when they come from whole food sources such as meat and dairy. There is a consensus that processed and fast foods are the most unhealthy sources dietary fats.