Of the three macronutrients – carbohydrates, fat and protein – none were alternately diabolized and worshiped as it did fat. Once a state enemy number one in the 80s and 90s, it is now the focus of the popular keto diet . In both scenarios, however, the surprisingly massive and complex role that fat plays in our body is not really clear. Let's talk about what fat actually does in the body.
What fat actually does.
Fats are one of the three macronutrients (nutrients we need in large quantities) that we find in our foods, in addition to protein and carbohydrates. According to Merck Manuals these surprisingly complex molecules represent the slowest and most efficient form of energy for our bodies.
Dietary fat is present in virtually all animal products, including meat, dairy products, eggs and fish. Fat is also found in many plant foods. Dietary fats are present in very high amounts in nuts, seeds, olives, avocados and coconuts – and in their purest form in oils of plants and plant seeds (such as olive oil, canola oil or safflower oil). But other plant foods like beans and even whole grains contain a small amount of fat.
Foods that consist almost exclusively of fat, such as butter, lard or vegetable oil, are classified as "fats" in nutritional science. While many animal products, such as milk, yogurt and ground beef, also contain relatively high levels of fat, we call them "proteins" because they are the highest in this macro. (In addition, the fat content is often reduced or removed during processing – eg skimmed milk or lean meat.)
The Different Types of Fats
The main fatty foods in food are triglycerides, Whitney Linsenmeyer Ph D., RD, nutrition and dietetics instructor at Saint Louis University's Doisy College of Health Sciences and spokesman for the Academy of Nutrition and Dietetics, reports SELF. Triglycerides consist of three fatty acids – a chain of hydrocarbons bound to a group of oxygen, hydrogen, and carbon – and a small compound called glycerol.
The way in which these chains are bound and their length determine exactly which type of triglyceride is present or is fat. There are three main types of fat, and although they taste equally good, they are quite different.
Saturated fats are simply fat molecules that are full (or "saturated") with hydrogen molecules American Heart Association (AHA). They are usually solid at room temperature and are most commonly found in animal products. However, they are also contained in significant amounts in coconut and palm oil (according to AHA ).
The second species is unsaturated fat, which is not completely saturated with hydrogen. There are two subtypes: monounsaturated fat molecules have a single unsaturated carbon bond, while polyunsaturated fats have more than one unsaturated carbon bond, explains the AHA . Both species are usually liquid at room temperature and occur in large quantities in fish, avocados, walnuts and various types of vegetable oils.
While foods often have higher levels of unsaturated or saturated fatty acids, each dietary fat contains some of Both types of fatty acids are regulated by the nutritional guidelines .
Transfette but a very different ball game. While they occur naturally in tiny amounts in meat, dairy and some oils, according to FDA most trans fats are artificially produced during an industrial process in which hydrogen is added to liquid vegetable oils to solidify them partially hydrogenated oils. The FDA banned these artificial trans fats, which are most common in deep-fried foods and processed baked goods, due to their association with heart disease . (Although the ban came into effect in June 2018, foods made before that date can be sold until January 1, 2020.)
Why We Need Fats Ever
Fat has an absurdly long to-do list We help our body, to work. First, fats deliver a ton of energy – they contain 9 calories per gram, compared to 4 calories in every gram of protein or carbohydrate – some of which are consumed immediately, much of which is reserved for later use of the carbohydrates (which our body prefers used as they are easier to break down and quick to use) are exhausted according to FDA .
But this macro makes so much much more energetic than us. Fat is a fundamental component of cell membranes in every cell of our body and therefore essential for the growth and development of the body. According to the FDA it is an essential component of body processes that range from blood clotting, to the functioning of the nervous system, to the reproduction and immune response of rich fats. For example, two of the essential fatty acids we need for brain development and function can be made with linolenic acid, a fatty acid found in certain vegetable oils and fish oils. explains Merck Manuals .
There are certain important vitamins that our body can absorb only with the help of fat (ie fat-soluble vitamins), such as vitamins A, D, E and K, which play a key role in maintaining healthy bones, teeth, hair, skin and kidneys play sights among others. As I said, pretty important.
Finally, fats can help regulate cholesterol levels. Unsaturated fats, according to AHA can help reduce LDL cholesterol (low density lipoprotein, also known as "bad cholesterol") and increase HDL (high density lipoprotein, up the thumb). which is associated with a lower risk of heart disease. (We'll talk more about lipoproteins soon.) However, consuming trans fats and large amounts of saturated fats, especially in place of unsaturated fats, has been shown to do the opposite: Increase your LDL and lower your HDL All that is why removing your body from dietary fat is generally not good for your health. If you eat very low in fat, you run the risk of not getting all the benefits we've just discussed. For example, a very low-fat diet can make it difficult for your body to absorb enough fat-soluble vitamins, explains the Mayo Clinic . This leads to vitamin deficiency and the associated negative impact you. A very low-fat diet can also deny your body the essential fatty acids it needs. If you do not eat enough fat, you will also miss the other nutrients that foods with modest and high fat levels have to offer.
What happens in your body when you eat fat?  The very first thing that happens when you eat fat? Your mouth will be happy. "Fats add to the mouthfeel by covering your mouth and helping you enjoy your meal longer," said Colleen Tewksbury, Ph.D., MPH, RD, Senior Research Investigator and Bariatric Program Manager, Penn Medicine and Pennsylvania President Elect Academy of Nutrition and Dietetics, tells SELF. This enhanced mouthfeel helps distribute the taste of the fat molecules to more taste buds where they can linger longer. This makes the taste of the food both more intense and more sustainable. (For example, think of celestial olive oil with garlic.) There are also investigations which suggest that we have special flavor receptors for the fat taste, much as we do for sweetness and saltiness.
As you smack your lips, your body prepares for the lengthy process of breaking down fats back into their basic components: fatty acids and glycerine. This requires a lot of tact on the part of our digestive system. "Fats are the best-preserved macronutrient in terms of digestion and absorption," says Linsenmeyer.
This is because the environment of the GI tract (and later of the bloodstream) is water based. And if you have ever tried to whisk olive oil and lemon juice, you know that oil and water can not mix well. "Because fat is insoluble in water, we have quite complex mechanisms to emulsify and degrade these fats, then absorb and transport them through the blood," explains Linsenmeyer.
This is one of the reasons why we digest fatty foods slower and feel longer, as if sticking to our ribs. While carbohydrates are great for this quick burst of energy, "fats literally slow down how quickly the stomach empties food into the small intestine," says Linsenmeyer, encouraging and prolonging the feeling of fullness.
The Entire Process Begins in the Stomach Tewksbury explains where the enzyme lipase is mixed in to break things up. As your partially digested food migrates into the small intestine, various organs in the mix add various juices and enzymes, many of which specialize in breaking down fat into smaller chains of fatty acids. A secretion is a digestive juice called bile, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Bile acts as an emulsifier that allows fat to blend into a water-based substance and enter the bloodstream, Tewksbury explains.
How the body transforms fat into energy
The blood from our gut with everything These tiny bits of fat migrate to the liver, which after digestion is a kind of macronutrient delivery center, Tewksbury explains, in which molecules are assembled into different forms can – like HDL, certain fatty acid chains -. based on what you have eaten and what your body needs before it is sent out for use or storage. There are a number of processes that can take place here – for example, the synthesis of the fatty acids that our brain cells or other organs need. "There are many different things that fat can be used for, and our body is really good at sorting it," says Tewsbury.
The liver often converts excess fat into a storable form around the Mayo Clinic . According to the Cleveland Clinic the glycerol and fatty acid molecules reassemble into triglycerides or cholesterol – the two types of fat in your blood. Then it needs to repackage them with proteins to form special small vehicles called lipoproteins which can transport the fats to where they are needed, Tewksbury explains.
Besides, fats are the only macro that gives it the help of the lymphatic system to get into our cells. (We said that you have high maintenance fats.) These lipoproteins are still a bit too large to be taken directly into the bloodstream, says Linsenmeyer, so they actually get into the lymphatic system first. This vascular network, which transports fluids throughout the body, is quite parallel to the circulatory system and has specialized channels that direct these bulky lipoproteins directly into the bloodstream.
Finally, these lipoproteins, the triglycerides, can chauffeur the circulatory system everywhere to its most common end goal: fat cells throughout the body, known as adipose tissue, in which energy is stored. (Incidentally, this is a good time to realize that the relationship between dietary fat and body fat is so much more complex than "eating fat = increasing fat.") This relic of early nutritional science does not consider the central role of, for example, total caloric intake plus many other variables in the weight gain equation. This is a scientific draft for another day.)
Later, when the body's preferred form of energy, glucose, is depleted – because you're exercising or between meals or not eating enough carbohydrates – your body can absorb the triglycerides stored in your fat cells actually split back into free fatty acids and glycerin and use them for energy in the form of glucose. (Sometimes, when the carbohydrates are removed from the body, the liver begins to break down fatty acids into another type of fuel called ketones – a process that forms the basis of keto diet, as reported by SELF ].)
Well, as absurdly complicated the whole thing is – seriously, if you're still with us – the reality is that there are actually a number of other processes taking place in our bodies when we eat fat that we are not , & # 39; This is not even addressed (for example, with different hormones). Many of these complex mechanisms occur at the cellular level and require some biochemistry to truly complete them.
What we are doing here is a comprehensive picture so you can better understand, on a more basic level, how the fat in the food you eat affects your body. Taking away is that fat is not only delicious, but also critical to your health – and that we are all blessed that our body knows exactly what to do when we eat it.