As with many things in the food and nutrition realm, the all-or-nothing approach towards major food groups does not skip over dietary fats. There are high-fat [ketogenic] diets and low-fat diets, sometimes recommended by professionals - other times chosen based off of internet research or magazine headlines.
Before deciding on what might be right for you, though balance is always a good bet, let’s look at the science-y facts behind fat.
The macronutrient, fat, is an essential part of life. While our body is capable of synthesizing a majority of fatty acids, two essential fatty acids must be obtained through the consumption of food. These two fatty acids are more commonly known as omega-3 and omega-6 [aka linoleic and alpha-linolenic fatty acids], and can be found in a variety of common foods. People with allergies or aversions to these foods can supplement their diets with fish oil products.
Healthy fat plays 3 major roles in the body:
Helps our body absorb certain nutrients
Regulates our temperature
Let’s look at these each a little more closely.
Typically carbohydrates are used to fuel the body, but once the body has run out of carbs, it switches to burning fat. For every gram of fat, our body is provided with 9 calories of potential energy [whereas carbohydrates and proteins only provide 4 calories]. For every pound of body fat, there are roughly 3500 calories [or 389 grams] that can be used for energy - so yes, this means you have to have a caloric deficit of 3500+ calories in order to lose a pound of body fat.
To tap into this plethora of stored energy, the body must be engaged in low to moderate intensity exercise for a long duration of time, where oxygen is present. This is different than shorter bursts of high intensity exercise, where carbohydrates are the main source of fuel.
Certain vitamins, dubbed fat-soluble vitamins, rely on fat to be absorbed by the body. Vitamins A, D, E and K can be found in the following types of foods:
Vitamin A: carrots, sweet potatoes, broccoli, spinach, apricots, cantaloupe, liver, egg yolks and fortified milk
Vitamin D: eggs, fatty fish [sockeye salmon, mackerel, sardines], grass-fed/fortified dairy [milk, yogurt]
Vitamin E: spinach, almonds, sunflower seeds, avocados, shrimp, rainbow trout, olive oil, broccoli, butternut squash
Vitamin K: dark leafy greens, scallions, brussels sprouts, broccoli, asparagus, cabbage
Some of these foods are already sources of healthy dietary fats, but for the ones that are not, they should be supplemented with an additional fat source. A great analogy found in an article by Abbey Sharp says “Consuming these vitamins [A, D, E, and K] without enough fat is like putting gas in the car but not having anyone in the driver’s seat. You’re not going to get anywhere with that full tank of gas (i.e. your big bowl of greens) without a designated driver (~fat!).”
Fat on our body has been described by some as a type of insulation. As unflattering as that sounds, scientifically, it is correct. Fat cells are stored in adipose tissue, which insulates your body. Certain types of adipose tissue help to generate body heat by tapping into the stored energy. If a body temperature drops too low, it an be lethal. (*Some people have more noticeable stores of this tissue than others aka cellulite, love handles, ‘bat wings,’ etc. In addition to adipose tissue, which is more visible from the outside, there is another type of stored fat, visceral fat, that surrounds and protects our organs. Visceral fat is a necessary protector, however like most things, too much is dangerous for your health. An example of excess visceral fat are those pregnant-looking old man bellies.*)
In next weeks article, you’ll learn the difference between “good” and “bad” fat and how eating low-fat can actually lead to the inability to lose weight. In the meantime, if you have questions about dietary fat send an email to firstname.lastname@example.org or sign up for Nutrition in a Nutshell.