Bad Fats VS Good Fats: Complete Fat Guide (Science Backed)

Have you always believed that all fats are bad for you? You’re not alone. However, the truth is, there are good fats and bad fats.

You might be surprised to know that good fat can help with weight loss. Yes, they can help you lose weight if you consume them the right way.

Here’s what you’ll learn in this guide:

  1. 4 main types of fat and their role
  2. 6 ways bad fats can damage your health
  3. 4 health benefits of good fats
  4. Low fat vs. high-fat overview
  5. 3 ways to add more healthy fats to your diet

By the time you finish reading this article, you’ll hopefully have a deep understanding of everything you need to know about dietary fat.

4 Types Of Fats And Their Functions

Contrary to the popular advice we have heard for decades; not all fats are bad for you. In fact, you need fat for essential bodily functions such as the absorption of vitamins and minerals. It also plays a vital role in building cell membranes.

That said, there are good fats and bad fats. Some types of fats can provide your body with health benefits, and some can do the opposite. This also means that some fats can help you lose weight, whereas some can make weight loss impossible.

The chemical structure of fats is what decides whether it’s going to be beneficial or detrimental for your health.

All types of fats are made of carbon and hydrogen atoms. However, what separates them from one another is the shape and length of the carbon chain and the number of hydrogen atoms attached to it.

Below are four main types of fats and their role in your body [1]:

1. Polyunsaturated fats

Polyunsaturated fats are essential fatty acids because your body needs, but it’s unable to produce them. Hence the only way to get them is via your diet. There are two main types of polyunsaturated fatty acids (PUFAs): omega-3 and omega-6.

PUFAs are considered good fats that can help reduce bad fats and improve your cholesterol profile. They have significant health benefits, such as offering protection against heart disease, which we’ll discuss in a bit.

Although both omega-3 and 6 are good for your health, the consumption of omega-6 is often higher. The reason for that is unlike omega-3, six is found in regular cooking oils like sunflower oil, as well as meat and poultry.

Omega-3, on the other hand, is primarily found in fatty fish, nuts and seeds, and fish oil supplements. Although both 3 and 6 are good, it’s best not to consume high amounts of omega-6 via processed vegetable oils.

Omega-3 can also help with weight loss by suppressing your appetite.

2. Monounsaturated fats

Polyunsaturated fats and monounsaturated fats are the two main types of good fats. The chemical structure of monounsaturated fats makes them liquid at room temperature.

Monounsaturated fat became famous for its health benefits during the rise of the Mediterranean diet. Some studies showed that people in Greece had a lower rate of heart disease despite consuming a large quantity of fat every day.

Researchers found that unlike people from other countries who consumed a lot of animal fat, people in Greece consumed a generous amount of olive oil every day.

Olive oil is a rich source of monounsaturated fat. Other foods rich in this fat include eggs, nuts, avocados, full-fat yogurt, coconut oil, and cheese.

The Mediterranean diet is a good choice if you wish to lose weight gradually and enjoy the health benefits of good fats.

3. Saturated fats

Saturated fats were also considered as bad fats in the early days. However, emerging research indicates that moderate consumption can be useful for your health. Therefore, it’s often regarded as the “in-between” fat.

Some food sources that are rich in saturated fats include fatty meat, lard, whole milk, most dairy products, and coconut oil.

Saturated fats may not be beneficial if you’re consuming them in large quantities in a free-living condition. This means you’re eating all kinds of unhealthy foods and living a sedentary lifestyle.

However, they may be beneficial and can help with weight loss if you consume them as part of a healthy diet.

4. Trans fats

Trans fats, also known as bad fats, are the ones you want to stay away from at any cost. They don’t have any health benefits but have plenty of health consequences, not worth risking.

Consuming trans fats can increase low-density lipoprotein (LDL) cholesterol and lower high density (HDL) in your blood [2].

LDL is bad for your health, and HDL is good. The reason why HDL is good is that it helps get rid of excess cholesterol so that it doesn’t end up blocking your arteries.

LDL, on the other hand, does the exact opposite and carries cholesterol to your arteries.

Trans fats are full of this bad cholesterol, and some examples include deep-fried foods, sugary sweets and snacks, margarine, and vegetable shortenings.

This fat can also make it harder to lose weight.

6 Ways Bad Fats Can Damage Your Health

Now that you know about the different types of fats, we’re going to discuss some of the ways bad fats can damage your health.

1. Increased risk of heart disease

One of the most significant ways trans fats can damage your health is by increasing your risk of developing cardiovascular diseases. One of the ways it does this is by increasing LDL cholesterol (bad fats) and decreasing HDL (good fats).

As stated earlier, increased LDL means you have more of this dangerous type of fat that contributes to the buildup of plaque in your arteries.

An older study by the medical school of Harvard investigated the connection between trans fats and heart disease. The researchers calculated dietary trans fat intake in 85, 095 women via questionnaires and did an 8-year follow up.

Their results showed that 69, 181 of those women had increased risk of coronary heart disease due to the consumption of trans fats. And 341 of them were identified with the disease. The bad fats they consumed were mostly in the form of margarine, cookies, cakes, and white bread [3].

2. Increased risk of type 2 diabetes

Trans fat intake could increase your risk of developing type 2 diabetes by increasing insulin resistance. The department of nutrition from the Harvard School of Public Health investigated this in 2002.

In this study, the researchers did a 14-year follow up on 84, 204 middle-aged women (34-59) who had no diabetes, cancer, or heart disease. They found 2507 new cases of type 2 diabetes during their follow up.

Their results showed that even a 2% increase in the intake of bad fats increased the risk of type 2 diabetes. However, saturated and monounsaturated fats did not increase risk. They also found that polyunsaturated fats reduced the risk [4].

3. Obesity risk

Consuming bad fats can significantly increase your risk of becoming overweight or obese. In one study, 42 male monkeys were assigned to either a monounsaturated (good fats) diet or a trans (bad fats) diet for six years.

The calories provided to the monkeys were only intended for their daily energy requirements and not to promote weight gain. However, their results showed that the monkeys in the trans fat group gained a significant amount of weight, especially in their abdominal region.

The study concluded that even without excess calorie consumption, trans fats could be considered as an independent risk factor of weight gain. They also noted that it increased insulin resistance [5].

What this means is that trans fats can hinder your weight loss and make it harder to lose weight, even if you watch what you eat.

4. Increased risk of cancer

Some evidence suggests that consuming trans fats could increase your risk of developing certain types of cancers such as breast and colon cancer.

An earlier study conducted in 1997 found a positive correlation between breast cancer and trans fatty acids in postmenopausal women. A more recent study conducted has also had similar results. In this cohort study, 30, 252 eligible postmenopausal women aged 50-76 years completed various types of questionnaires.

Their results showed a positive association between breast cancer and some types of saturated fats such as palm oil and animal fat. Trans fats such as partially hydrogenated vegetable oils were also associated with an increased risk [6].

5. Bad for pregnant women

Pregnant women consuming trans fats could pass it on to their babies. In one earlier study, the fatty acid profiles of 41 pairs of mothers and their newborns were investigated.

Their results revealed that trans fatty acid percentage of the newborns was almost the same, if not a few percentages lower as their mothers [7]. Recent research states that trans fatty acids can also be passed on via breastmilk.

In one animal study, researchers wanted to find out if trans fat exposure in utero and lactation would promote obesity in mice. They found that mice exposed to bad fats in utero grew rapidly after birth. They also noted that the newborn mice also had significantly damaged insulin sensitivity and larger abdominal fat [8].

6. Systematic Inflammation

Consuming trans fats can cause systematic inflammation, which in turn can contribute to a lot of chronic diseases.

One study investigated the trans fatty acid profiles of 86 ambulatory patients with heart failure. Their results showed a strong association between bad fats and systematic inflammation in the patients [9].

A cohort study found that a higher intake of trans fats was positively linked to an increased risk of all-cause death [10].

4 Health Benefits of Good Fats

Remember how we said not all fat is bad for you? Well, here are some ways good fats can boost your health.

1. Weight loss

Consuming good fats can help with weight loss in several ways. E.g., it can help you lose weight by reducing your appetite and making you feel fuller for longer. As a result, you may consume fewer calories than usual and also have better control over your cravings.

E.g., In one study, six volunteers were allowed to eat as they pleased for three weeks. After 10-12 weeks, the participants were asked to eat in the same format, but this time with 6 grams of fish oil per day for another three weeks.

Their results showed that despite having consumed the same amount of calories, fish oil promoted fat oxidation and reduced body fat mass [11].

2. Reduced risk of heart disease

Good fats can help protect your heart. One example is the Mediterranean diet story we discussed earlier. The reason why this diet is also known as the ‘heart-healthy’ diet is that it allows a generous consumption of olive oil every day.

Olive oil is a rich source of monounsaturated fat, and it has been proven to be good for heart health. In one cohort study, researchers investigated the connection between the Mediterranean diet and heart health in 40, 757 people.

The 11-year follow up study revealed that the Mediterranean diet reduced the risk of coronary heart disease [12].

3. Improved brain health

Adding good fats to your diet can help improve your brain health. E.g., in one study, researchers examined the effect of omega-3 supplementation on learning and memory power in older adults.

In this double-blind trial, forty four cognitively healthy women aged 50-75 years were divided into two groups. One group received 2200 mg of the omega-3 capsule per day for 26 weeks, while the other group received a placebo for the same duration [13].

Their results revealed a significant improvement in the memory function of the participants, especially in recalling object locations.

4. Immune boost

Good fats such as polyunsaturated fatty acids can boost your immune system and offer protection against inflammation. Some research indicates that consuming 3-PUFAs can modulate the lymphocyte and affect the function of the immune system cells.

Studies have also shown that a diet rich in healthy fats is packed with anti-inflammatory and immunosuppressive properties. This also means they can protect against some chronic diseases [14].

A recent research paper published in 2019 has also confirmed this and stated that long-chain PUFAs could protect against chronic immune disorders such as food allergies [15].

What Science Says About Low-Fat vs. High Fat Diet

Even until a couple of decades ago, the consumption of dietary fat was always frowned upon. Fat intake was always seen as something that can make you gain weight and increase your risk of heart disease.

However, that’s not the case anymore. Plenty of old and new research has confirmed that not all types of fat are harmful to you. As discussed in this article, there are good fats and bad fats.

The key to good health is in what type of fat you eat and how you eat it. We’ll discuss more on this in the next section.

Did you know a high-fat diet can be better than a low-fat one?

As shocking as it may be for some of you, emerging research supports a high-fat diet over a low-fat one.

One of the primary reasons for that is back in the days when doctors often recommended a low-fat diet; people consumed a lot of foods labeled as ‘low fat.’

What they weren’t aware of is that a lot of these foods were high in refined carbohydrates and sugar as a replacement for the “low fat.” E.g., one systematic comparison study found that the low fat and non-fat versions of some foods contained more sugar than the regular version [16].

But won’t consuming more fats make it difficult to lose weight?

You’ll be surprised to hear that eating more fat won’t make you fat. However, as stated earlier, the key is in what type of fat you eat and how you eat it.

E.g., contrary to popular belief, eating eggs won’t make you gain weight if you eat them the right way. If you eat a lot of eggs as part of a high-calorie diet and live a sedentary lifestyle, you will put on weight. There’s no surprise in that.

However, if you eat eggs as part of a healthy balanced diet and are more physically active, you’ll not gain excess weight. Some studies have even shown that eating eggs can help with weight loss.

In one study, 152 overweight and obese participants (aged 50-60 years) were divided into four groups [17]:

  • Egg group (2 eggs for breakfast)
  • Bagel group (2 bagels for breakfast)
  • Egg diet (1000 calories per day)
  • Bage diet (1000 calories per day)

The participants followed this eating pattern for eight weeks. The egg and bagel breakfast groups were told not to change their calorie intake. Their results showed a significant reduction in all the weight-loss parameters of the egg diet group compared to the bagel diet group.

The study concluded that consuming eggs can help you lose weight when you combine it with a calorie-restricted diet, as we stated earlier.

It’s not always about high fat vs. low fat

Sometimes it’s not always about high fat vs. low fat, especially when it comes to losing weight.

Otherwise, so many people won’t be raving about the weight loss benefits of the ketogenic diet.

For those who don’t know, it’s a diet that calls for at least 65-80% of your daily calories to come from fats. What makes it stand out, however, is that it also requires you to have no more than 10% of your daily calories from carbohydrates.

This puts your body in a metabolic state called ketosis, which has many proven health benefits. In one study, 83 obese patients were administered the high-fat ketogenic diet for 24 weeks.

Results showed a significant reduction in body weight and BMI of the patients. Their LDL cholesterol (bad fats) also decreased while HDL cholesterol (good fats) increased [18].

3 Ways To Reap The Health Benefits Of Good Fats

The tips below can help if you want to increase your dietary fat without gaining weight. They may also help with weight loss.

1. Avoid foods labeled ‘low fat.’

As stated earlier, foods labeled as ‘low fat’ are bad news because they’re often loaded with refined carbs and sugars to replace the fat.

So avoid those and aim to get your fat from healthy food sources such as nuts, seeds, fatty fish, and fish oil supplements.

2. If weight loss is your goal:

Look back at the egg breakfast study we discussed in the previous section. You’ll notice that you can lose weight with fat if you eat it with a restricted-calorie diet.

So use a weight loss calculator to find out how many calories you’ll need daily to eat to lose weight. We strongly advise against going on extremely low-calorie diets as they can do more harm than good.

Even those who don’t like exercise might find it easier to do high-intensity interval training (HIIT) workouts. HIIT is proven to help lose weight, especially for belly fat, and it can be done in 7-10 minutes per day. You don’t need any special equipment, and you can even do it in the comfort of your bedroom.

A high-fat low-calorie diet with 3-4 days per week of HIIT exercise is a powerful strategy for weight loss.

3. Consider taking MCT oil

MCT oil is a supplement made from the good fats of coconut oil. It has many proven health benefits, such as improving your energy, boosting weight loss, and improving your brain function [19].

Be careful with the dosage, though, and start with one or two teaspoons per day for two weeks until your body gets used to it. The maximum recommended dosage is said to be 2 tbsps per day, and anything more could cause adverse effects.

Takeaways

  1. The two main types of good fats are monounsaturated and polyunsaturated fats. Food sources rich in these types of fats include nuts, seeds, fatty fish, eggs, and fish oil.
  2. Adding healthy fats to your diet can provide health benefits such as immune boost and protection against chronic diseases.
  3. Some saturated fats are also good for you when eaten moderately, and these include butter, cheese, and coconut oil.
  4. Trans fats are also known as bad fats because they can increase your risk of developing cardiovascular disease and other health conditions.
  5. Contrary to what we’ve been told for decades, healthy fats can help you lose weight if you eat them the right way, as discussed in this article.

 

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