Are All Fats Bad?

Medically reviewed by Mary Ahern MS, RDN, RYT April 15, 2024| Written by Shahid Bashir

Are All Fats Bad?

Fats are hydrocarbon chains comprising varying amounts of carbon, hydrogen, and oxygen. Unlike carbohydrates and proteins, fats have a higher ratio of carbon and hydrogen bonds in their structure. This composition makes the fat denser in energy comparatively.

A breakdown of one gram of fat gives nine calories, while one gram of carbohydrates and proteins only gives four calories.

Since they are more calorie-dense, there is a common perception that fats are bad and unhealthy. However, this doesn’t apply to all fats; instead, fats play some vital roles in the body. Fats are a good energy source, a component of cell membranes, protect organs, and help the body absorb nutrients.

Fatty acids are the primary units of fats. The fatty acids that your body can produce by itself are called non-essential fatty acids. However, the body must rely on a fatty diet to get essential fatty acids that it cannot produce. 

Fats are classified into good and bad fats depending on their effects on the body. Unsaturated fats are good for your body, and there should be an adequate supply of them for the normal functioning of the body. 

On the other hand, trans fats are harmful to your body, and you must avoid consuming them. Saturated fats are not as harmful as trans fats but certainly are not a healthy choice.

So, how much fat intake is not too much?

WHO recommends limiting your fat intake to 30% of your total energy intake. The major portion of this 30% must come from unsaturated fats. Saturated fats and trans fats should not exceed more than 10% and 1% of total energy intake, respectively.

Is it Healthy to Cut Out All Fats?

You probably have heard a lot about the harmful impact of fats on our bodies. It is a common idea to link weight gain, cardiovascular problems, and many other diseases to fat intake.

However, this is only true to some extent, as not all fats are bad for your health. Your body requires a decent portion of fat from your diet to perform several important functions. 

It is certainly not healthy to cut out all the fats; instead, you can consume fats in moderation to get all the benefits with little to no harm to the body.

Some of the complications that can arise from cutting out all fats are:

a) Weight Gain

Besides fats being high in calories, cutting down on all fats could potentially increase the risk of weight gain. Fats have aslower digestion rate than carbs and proteins; thus, they stay in your digestive system longer. This makes you feel satisfied, and you don’t feel the need to eat more frequently.

Research shows low-fat foods tend to be higher in refined carbohydrates, which are high in sugar and can lead to weight gain.

b) Vitamin Deficiency

Vitamins A, D, E, and K are fat-soluble vitamins that have an integral role in severalphysiological functions in the body. As they are fat soluble, your body can only absorb them from your diet if you consume them with fats.

Cutting out all the fats will result in thedeficiency of fat-soluble vitamins and can affect vision, bone health, immune function, and coagulation.

c) Inefficient Immunity 

Fat-soluble vitamins A and D have a significantrole in immune system functioning. Cutting out all fats in the diet will lead to vitamin deficiency and affect the efficiency of the immune system.

d) Cardiovascular Problems 

A diet high in saturated fats is indeed the major cause of cardiovascular problems. However, good fats like monounsaturated and polyunsaturated fats aregood for heart health and can prevent cardiovascular problems.

e) Memory Problems 

Fats are an important structural and functional component of the brain cells.Studies show that consumption of omega-3 results in improved learning, memory ability, cognitive well-being, and blood flow to the brain. 

Hence, cutting out all fats will cause a deficiency of good fats like omega-3, leading to memory and focus problems.

Debunking Myths About Eating Fats

Among macronutrients, fats never had a good reputation in terms of their health benefits. It is common to associate fat consumption with the incidence of several diseases. The major problem behind this misconception is the lack of knowledge about the difference between good and bad fats.

Here are some common myths about eating fats and what scientific data says about these myths:

Myth 1: All Fats Cause Weight Gain!

If you are searching for ways to lose weight, you probably have come across the idea that cutting out fats helps in weight loss. It is true up to a certain point as fats provide thehighest calories per gram compared to other nutrients.

However, if you consume unsaturated fats in moderation, there is no risk of weight gain.Research shows that 20 to 30 percent of energy intake from unsaturated fats can help lose weight. 

There are different studies to understand the exact mechanism by which fat helps in losing weight. The most valid belief is that fat slows digestion andmakes you feel satiated for longer. You tend to consume food less frequently, which helps regulate calorie count. 

Low-fat diets are oftenhigh in refined carbohydrates. Studies show that consuming refined carbohydrates causes increased adiposity and insulin resistance,leading to obesity.

Myth 2: All Fats Cause Heart Problems

The statement that fats cause heart problems is true for unhealthy fats like saturated and trans fats as these tend to increase LDL cholesterol or bad cholesterol in the blood. Trans fats even have the added unhealthiness of decreasing HDL or good cholesterol. 

The high levels of LDL cholesterol result in the formation of plaques in the arteries and can lead to heart attack and stroke. 

However, unsaturated fats work opposite to unhealthy fats andlower the LDL cholesterol levels in the serum. There is alsoevidence that omega-3 fatty acids, which are polyunsaturated fatty acids, increase healthy HDL cholesterol and prevent heart diseases.

Remember that even healthy fats are good only when used in moderation. Overconsumption can cause complications like weight gain and heart disease. 

Myth 3: All Fats Increase Diabetes Risk!

Unfortunately, your body is really efficient at storing excess dietary fat as body fat. When you consume more fats than the calorie requirements of your body, the excess fat starts to accumulate in the body. This can increase the body mass index, which islinearly related to type 2 diabetes. 

However, if you replace saturated and trans fats with unsaturated fat and consume it at recommended levels, itincreases insulin sensitivity and is likely to reduce the risk of type 2 diabetes. 

Scientific research found that just a shift of 5% of total energy intake from carbohydrates and saturated fats to unsaturated fats lowers the HbA1c by 0.1% — HbA1c is a blood marker indicating blood sugar level over the past two to three months. A 0.1% decrease in HbA1c translates to a reduction of 22% in the incidence of type 2 diabetes. 

Myth 4: Dairy Fats are Always Healthy!

Dairy products have plenty of nutrients and health benefits. But when the debate is about dairy fat, people often consider them a healthy fat choice, which is a misconception. 

Dairy products are rich in saturated fats, which is a threat to cardiovascular health. Saturated fats increase blood cholesterol levels, making the cardiovascular system more susceptible to diseases. While there are many healthy things in dairy, this is why the daily recommended intakes for dairy are typically low. 

Myth 5: Low-Fat Diets are Always Healthy!

Because of the bad reputation of unhealthy fats, people consider cutting out fat in their diet healthy. However, as soon as you lower your dietary fats than the recommended count, you will not benefit your health. 

A low-fat diet lowers the absorption of fat-soluble vitamins, can cause weight gain, reduces the efficiency of the immune system, and lowers cognitive abilities. 

Instead of lowering the overall fat in your diet, experts recommend a shift from trans fats and saturated to monounsaturated and polyunsaturated fats.

What Kinds of Fats are Good for You?

Unsaturated fats that originate from vegetables, nuts, seeds, and fish are good for your health. Unsaturated or good fats are mostly liquid at room temperature. There are two main categories of good fats: monounsaturated and polyunsaturated fats. 

a) Monounsaturated Fats

Fat molecules are called unsaturated when they have one or more double bonds between carbon atoms. In monounsaturated fats, there is one carbon-carbon double bond, which makes these molecules liquid at room temperature.

Monounsaturated fats lower the risk of heart disease bylowering bad cholesterol (LDL) in the blood. The other benefits of monounsaturated fats include increasinginsulin sensitivity,reducing cancer risk, andweight loss.

Somerich sources of monounsaturated fats are:

  • Olive Oil
  • Almonds
  • Cashews
  • Peanuts
  • Avocados
  • Sunflower seeds

b) Polyunsaturated Fats

Polyunsaturated fats have two or more double-bonded carbons in their molecules. They are also liquid at room temperature, like monounsaturated fats.

Thehealth benefits of polyunsaturated fats include reducing the risk of heart disease, diabetes, cancer, mental illness, and age-related cognitive decline.

Two well-known and popular polyunsaturated fats are omega-3 fatty acids and omega-6 fatty acids. The difference is based on the position of the carbon double bond in the molecule.

Somerich sources of omega-3 fatty acids are:

  • Fatty Fish
  • Seeds and nuts
  • Plant oils
  • Fortified foods

Somerich sources of omega-6 fatty acids are:

  • Safflower oil
  • Sunflower oil
  • Corn oil
  • Soybean oil
  • Walnuts
  • Pumpkin seeds

What Foods Contain Healthy Fats?

To balance your diet with healthy fats, you must know what foods will give you how much healthy fats. Here are some foods that can provide you with adequate healthy fats:

1. Fish

Fish, especially fatty fish such as salmon, trout, tuna, herring, and mackerel, are high in unsaturated fats. Omega-3 fatty acids are the most abundant polyunsaturated fatty acids in fatty fish.

Studies suggest that if you consume fatty fish regularly, you are at alower risk of developing cardiac diseases. Other benefits of fatty fish are that itreduces blood sugar levels and helps inboosting cognitive functioning.

TheAmerican Heart Association recommends consuming two servings of fatty fish per week — one serving equals 3 Oz cooked or ¾ cup of flaked fish.

2. Avocado

The nutritional profile of avocado makes it one of the most healthy fruit options. Avocados are rich in monounsaturated fatty acids, the most abundant of which are oleic acid, linoleic acid, and linolenic acid. 

Studies show that two servings of avocado per week reduces cardiovascular disease risk by 16% and coronary heart disease by 21% in both men and women when avocado replaces saturated fat. Besides good fats, avocados are rich in other nutrients like potassium and fiber.

3. Nuts

Nuts have plenty of unsaturated fatty acids, with monounsaturated fatty acids being the most abundant. Polyunsaturated fatty acids such as omega-3 fatty acids and omega-6 fatty acids are also present in nuts.

Studies suggest that frequent nut consumption can reduce the risk of type 2 diabetes and cardiovascular diseases. There are several potential mechanisms by which nuts may reduce the risk of disease. One may be by increasing glucose and lipid metabolism, improving endothelial function, and weight management. Another potential mechanism is through nutrients present in nuts, including fiber and polyphenols.

4. Seeds

Seeds such as flaxseeds, chia, pumpkin, and sunflower seeds have a good portion of unsaturated fats. You can get plenty of omega-3 fatty acids from these seeds.

Omega-3 is effective inreducing the rate of sudden death from cardiac problems. It alsolowers the incidence of heart attacks and stroke by improving good cholesterol levels.

5. Olive Oil

Unsaturated fatty acids account for85% of the composition of olive oil. It has the highest proportions of monounsaturated fatty acids followed by polyunsaturated fatty acids. 

Evidence shows that unsaturated fats in olive oil make it effective against coronary, autoimmune, and inflammatory disorders. Olive oil also has antioxidant properties and effectively regulates blood pressure.

What Fatty Foods to Avoid?

As Important as consuming a good portion of fat in your diet, it is equally important to analyze the source of fats. Is the fat you consume is unsaturated, saturated, or trans fat? Are the food sources you are choosing for fats healthy or not?

To protect your body from the disadvantages of fats, you should limit these fatty foods:

1. Fried Food

Fried foods may contain trans fats and calories, which makes them unhealthy. Trans fats become a part of fried food when the oil is high in trans fats, or you fry at extremely high temperatures.

Trans fats in fried foods are a significant risk factor for causingcardiovascular problems. The otherharmful effects of trans fats include an increase in the risk of developing cancer, diabetes, and obesity. 

2. Red Meat

Red meat, like beef, pork, or lamb, is high in saturated fats. 

Saturated fatsincrease the LDL cholesterol in the blood, increasing the risk of developing heart diseases. A diet high in saturated fats also makes the bodysusceptible to obesity and complications related to obesity.

3. Processed Meat

When red meat undergoes processing to improve its durability, texture, and taste, it is called processed meat. Some common examples of processed meat are bacon, sausages, and hot dogs.

 Processed meats are typicallyhigh in saturated fatty acids, which is not a recommended healthy fat. Processed meat overall has high calories and cancontribute to obesity.

4. Full Fat Dairy Products

Full-fat dairy products like cheese, butter, and milk contain a high proportion of saturated fats. 

High concentrations of saturated fats bring full-fat dairy products among the food items you must consume in moderation. Overconsumption can lead to the harmful effects of saturated fats, which include weight gain and cardiovascular problems. 

5. Bakery Items

Bakery items such as cakes, cookies, muffins, bread, and pastries are high in saturated and trans fats.Studies show that consumption of bakery items is associated with increased LDL cholesterol.


It is easy to believe that fats are unhealthy for health because of the widespread misconceptions about their use. However,scientific evidence proves that fats are necessary as structural and functional components of the body.

Understanding the difference between healthy and unhealthy fats is important before you make your next diet plan. Unsaturated fats have many benefits, such as losing weight, absorbing vitamins, enhancing immune and cognitive functioning, and decreasing cardiovascular problems. 

Saturated and trans fats are not healthy choices as they increase the risk of developing cardiovascular problems, obesity, and diabetes.

Unsaturated fats are healthy only when you consume them in moderation.