Fat is an essential nutrient that you need for normal health and functioning. It's also the central ingredient of a ketogenic diet. However, not all fat is created equal; some types of fats prevent chronic diseases while others can harm your health. But what are good fats exactly and what distinguishes them from bad fats?
In this article, we go over the facts on fat, including what fat is, why you need it, and which ones you should choose. We'll also talk about why fat causes so much controversy. If you want to know the truth about fat and which fat you need to eat more of, keep scrolling.
By now, almost everyone knows that fat does not make people fat. Too many calories and too little exercise is what makes people gain extra weight. Still, the myth that fat is fattening persists as evident by low-fat advertising and media propaganda.
Then there's also the wide-accepted belief that too much fat in your diet causes atherosclerosis, putting you at risk of heart attacks and stroke. Fat is also blamed for diabetes, high blood pressure, and even cancer. The reality, however, is that fat is a nutrient that your body needs for a range of functions. Your body needs fat for the following reasons:
- Absorbing fat-soluble vitamins
- Building cell membranes
- Wound healing
- Hormone regulation
- Organ and nerve insulation
- Body temperature regulation
- Energy production
- Energy storage
The main reason why fat is portrayed negatively is that it provides more than double the calories per gram of either carbs or protein . Another reason is that studies carried out since the 1940s found a link between fat intake and heart disease . However, most studies failed to explain this link, and current research states that the dangers of fat have been blown out of proportion .
Yes, too much of bad fat can harm your health, but this holds true for any other nutrient. The body needs balance to stay healthy. If you add a lot of fat to your diet, you'll need to cut down on carbs and protein. The keto diet is based on this fact. So, how much fat can I eat for good health and what kind?
What Are Good Fats & Bad Fats?
Many types of fats exist in nature. Fats are known in chemistry as fatty acids and they can be either saturated or unsaturated. In your body, however, fats exist in the form of triglycerides, phospholipids, and cholesterol.
Monounsaturated fatty acids (MUFAs)
There are many different types of MUFAs, but oleic acid is the most common (90% of all MUFAs in food is oleic acid).
Good sources are olive, canola, and safflower oils, which are over 70% MUFAs . Lard is 40% and butter is around 30% MUFAs. Other great sources are grapeseed oil, avocados, almonds, sesame seeds, and oatmeal.
MUFAs lower bad cholesterol which studies show protects cardiovascular health . MUFAs from olive oil provide the strongest protection according to current research . A possible explanation for this is that olive oil also contains powerful antioxidants that contribute to this heart-protecting effect.
The greatest consumers of MUFAs are people in Mediterranean countries. People in these regions have lower incidences of heart disease and are known for their longevity. Mediterranean staples include olive oil, vegetables, nuts, and lamb, all rich in MUFAs.
Food Sources of MUFAs:
- Olive oil (75%) – Olive oil is the healthiest fat on Earth that will save humanity from cardiovascular disease according to current research. It has anti-inflammatory, antioxidant, and vasodilatory properties which all support the cardiovascular system.
- Avocados (71%) – Avocados are actually 30% fat, but most of that fat is MUFAs. It's rich in vitamin E, fiber, and low in carbs making it a keto favorite.
- Canola oil (60%)– This oil is derived from rapeseed. Canola oil is usually refined because oils high in MUFA are prone to rancidity unless they're also high in antioxidants like olive oil.
- Peanut butter (25%) – Peanut butter also contains a substantial amount of MUFAs. It's a nutrient-dense food that can boost your intake of potassium, magnesium, vitamin B6, and protein. Always go for the sugar-free kind on keto.
Polyunsaturated fatty acids (PUFAs)
PUFAs are not only good, they're also essential because your body can't make them on its own but needs to get them from food. The two well-known omega-3 and omega-6 fats are both PUFAs. Your body needs to get these fatty acids from food for cell growth and brain functioning.
You can get PUFAs from a range of plant and animal foods, like fish, nuts, seeds, and vegetable oils. These fatty acids lower bad (LDL) and raise good (HDL) cholesterol. Omega-3s are especially good because they also lower inflammation making them helpful in preventing autoimmune disorders, diabetes, depression, and cancer .
When it comes to PUFAs, your focus should be on eating more omega-3s. Research shows that our intake of omega-3s has declined by 80% over the last century while our intake of omega-6s increased . This created an unhealthy imbalance that promotes inflammation as omega-6s are pro-inflammatory.
Food Sources of PUFAs:
- Fatty fish – Salmon, tuna, and mackerel are the best sources of omega-3 fatty acids you can find. Our bodies use omega-3s more efficiently from animal sources than from plants, and fish happens to be the most abundant in omega-3s of animal foods.
- Walnuts– Most nuts are a good source of PUFAs, but walnuts take the lead when it comes to omega-3s. Keep in mind that omega-3 fatty acids are prone to rancidity which takes away some of their health benefits. Choose fresh walnuts and store them in a cool, dark place to keep them fresh.
- Chia seeds – Chia seeds are one of the best plant sources of omega-3 PUFAs. The seeds contain up to 30% oil of which over 50 % are omega-3s. They're also a good source of thiamin, calcium, iron, and magnesium.
- Omega-3 eggs – Some farmers feed their chicken with flaxseed and even algae so their meat and eggs contain more omega-3s. You can find these eggs in many supermarkets and health food stores.
Also known as trans-unsaturated fatty acids, trans fats are rarely found in nature but abundant in artificial foods. They're also the only fat you'll want to exclude from your keto diet.
These fats are directly linked to heart disease, breast cancer, short pregnancies, nervous system disorders, cancer, diabetes, allergies, and obesity .
Trans fats are particularly bad because they reduced good and raise bad cholesterol, spelling a double whammy for heart disease. These fats also increased triglyceride and lipoprotein levels and reduced LDL particle size, all of which spells disaster for cardiovascular health .
Meat and dairy foods contain a small number of trans fats (1-3%). These amounts don't pose any real danger to your health. But partially-hydrogenated oils, for example, contain 45% trans fats. Some brands of vegetable shortening can contain up to 30% trans fats while margarine can contain 15% trans fats.
Luckily, most countries today now prohibit trans fats. You'll find trans-fat-free margarines and likely won't see partially-hydrogenated oils in your food anywhere in the years to come. New methods of making margarines (interesterification) and other substitutes have made it possible to exclude these harmful fats from our diets.
Food Sources of Trans Fats:
- Some margarines – Manufacturers traditionally made margarines through hydrogenation, a process that turns liquid oils into solid ones. This process increases the trans fat content in these oils. Today, many brands use fractionation and interesterification, instead to make trans-fat-free margarines.
- Partially-hydrogenated oils – When buying processed foods like peanut butter or whipped topping, read the label and you may find partially-hydrogenated oils. The same goes true for any other processed foods.
- Vegetable shortening – Many shortening brands are reducing the amount of trans fat in their products. Still, 100 grams of shortening can contain up to 13% trans fats. It's best to go for natural shortening instead.
Saturated fats are primarily found in animal foods like butter, meat, and lard. But you'll also find them in coconut and palm kernel oil.
Medical experts are undecided about their exact effects on human health. Despite this, you'll notice that the general claim is that they're unhealthy. But keto community disagrees with this strongly, and we'll explain why.
The idea that saturated fats cause heart attacks came to be when researchers noticed a link between saturated fats, rising cholesterol levels, and heart disease. This lead to the advent of what is known as "diet-heart hypothesis," – that replacing saturated fat for liquid oils will prevent heart disease. The hypothesis was enforced by governments in the 1970s, the media followed suit, and the idea that saturated fat is bad prevails to this day.
However, scientists are now disputing this hypothesis, saying that cutting down on saturated fats doesn't translate to a lower risk of heart disease . The global rise in obesity, heart disease, and diabetes despite people removing saturated fats from their diets proves that saturated fat is not the problem. Instead, carbs are more likely the problem as evident by current research .
So, is saturated fat good or bad? It's really neither. Saturated fat has been a part of the human diet since humans began eating meat and dairy. Eating this type of fat in moderation will give you energy and help your body absorb fat-soluble vitamins. Many foods containing saturated fats also contain valuable vitamins and minerals, so it would be a shame to avoid them.
Food Sources of Saturated Fats:
Butter– Butter is 80% saturated fat, of which 60% is saturated. Butter also contains a short-chain fatty acid called butyric acid. It's linked to good gut health and balanced metabolism.
- Meat– Red meat, poultry, and pork all contain saturated fats in varying amounts. However, most meats also contain unsaturated fats as well.
- Dairy – The higher the fat content of the dairy product, the more saturated fats you get. We suggest sticking to cheese, cream, and full-fat yogurt on a keto diet to boost your fat intake.
- Coconut oil - Coconut oil is 90% saturated fat. In fact, it contains more saturated fat than lard or butter, so you'll often hear doctors advising against it. But coconut's saturated facts have a different molecular structure than animal fats, and they come with unique health benefits.
Cholesterol is a waxy, fat-like substance that your body makes from fats, carbohydrates, and proteins. It is an essential structural component of cell membranes, so you need a bit of cholesterol circulating your blood. Too much, however, clogs your arteries and can give you a heart attack.
Many people are confused about dietary cholesterol and its effects on blood cholesterol. Even medical experts often recommend limiting your intake of foods high in cholesterol. But only 20% of the cholesterol in your body comes from these dietary sources . The rest your body makes on its own. Dietary cholesterol comes from animal foods like dairy, meat, and eggs.
Of cholesterol-containing foods, eggs are the most controversial. You've probably come across recommendations stating not to eat more than 6 eggs a week. But one recent study shows that eating 12 eggs a week for up to a year does not increase your risk of cardiovascular disease, even if you're pre-diabetic . And there are many other studies showing the same results .
Food Sources of Cholesterol:
- Chicken liver – There are 355 mg of cholesterol in 100 grams of chicken liver. Chicken liver is a good source of iron, B vitamins, vitamin D, and protein.
- Eggs– Eggs contain a similar amount of cholesterol as chicken liver. All of the cholesterol is found in the yolk which led many people to avoid eating the yolk and stick to egg whites. But the yolk is where all the valuable vitamins, minerals, and fats are so we suggest eating the whole egg for maximum nutrition.
- Shrimp – Shrimp is another high-cholesterol food. Still, no one would talk about shrimp as unhealthy. It's rich in omega-3 fatty acids, iodine, and protein.
Good fats are fats that don't cause inflammation and raise blood cholesterol. Poly and monounsaturated fatty acids generally fall under this category while saturated and trans fats are considered the bad guys.
However, research is now revisiting the role of saturated fats in heart disease. As it turns out, this fat has been unfairly vilified, and it definitely has a place in a healthy diet. The reason being that there's no evidence that it increases the risk of heart disease despite raising both types of cholesterol shortly after a meal.
Trans fats are a different story. They're rare in nature but abundant in processed foods. They raise bad while lowering good cholesterol while also increasing triglycerides levels. Studies have definitely confirmed that they're particularly bad for heart health, so do avoid them at all costs.
Bottom line is to eat lots of healthy unsaturated fats and be moderate (but not avoid) saturated fats. This way, you'll be eating plenty of nutritious and wholesome foods. There's no reason to be afraid of fats from nature. Just be careful with anything man made.