Healthful fats include plant oils like extra-virgin olive oil, flax seed oil, sesame oil, walnut oil, and fats from whole plant sources such as olives, nuts, seeds, and avocado.
- Different types of fat can be either healthful or bad for you.
- Healthful fats can protect against cancer and help with the absorption of nutrients.
- Unsaturated and polyunsaturated fatty acids can be healthful, including omega 3, which is found in fish.
- Trans fats should be avoided.
- You can reduce your health risks by replacing good fats with bad fats in the diet.
Health benefits of fats
Oily fish, avocados, and certain types of nuts are vital sources of healthful fats.
Fat gets a bad rap, and we often try to avoid it. However, fats play a key role in the diet. They not only supply energy, but also help us absorb the fat-soluble vitamins A, D, E, and K, and carotenoids. They also provide, or help the body to synthesize, essential omega-3 and omega-6 fatty acids. All body tissues need these to function normally.
A deficiency in these fatty acids can lead to a range of disorders, including:
- liver and kidney problems
- reduced growth rates
- decreased immune function
- dry skin
Dietary guidelines recommend that an adult should get 20 to 35 percent of their energy intake from fat, and limit saturated fat to less than 10 percent of total calories. A 2,000-calorie-a-day diet should aim for 44 to 78 grams of total fat and no more than 22 grams of saturated fat to be within these guidelines.
However, the right kinds of fats bring a range of health benefits, if consumed wisely. Olive oil, for example, appears to have antioxidant, anti-inflammatory, antimicrobial, anti-cancerous, anti-diabetic and anti-aging effects.
Fats keep people healthy in other ways, too.
Protection against cancer
According to the American Institute for Cancer Research (AICR), walnuts, which are high in fat, may help to reduce the risk of breast cancer. They are also particularly high in omega 3s compared to any other nut. Omega 3s are important for brain and heart health.
There is also evidence that healthy fats can help people manage diagnosed colon, prostate, and breast cancer.
Healthy fats should be consumed with every meal, because many nutrients are fat-soluble. For example, the body cannot absorb beta carotene, or Vitamin A, D, E, or K without fats.
- Beta carotene, which functions as vitamin A, is also one of the body's most powerful antioxidants. It helps to minimize cell damage.
- Vitamin D plays a role in hormone production and regulation, neuromuscular function, and immune function.
- Vitamin E is a powerful antioxidant that is vital for immune function and gene expression, and it works to minimize heart disease risk.
- Vitamin K is involved in your body's natural ability to clot blood and is important for bone health and heart health.
Some antioxidants that are present in fruits and vegetables also need fat for metabolism. They can help promote cardiovascular health, maintain a healthy weight, and prevent obesity.
In one study, people who ate salads with fat-free salad dressing absorbed far less of the helpful phytonutrients and vitamins from spinach, lettuce, tomatoes, and carrots than those who ate their salads with a salad dressing containing fat.
Cutting out fat can lead to diabetes
People who avoid fats often eat a higher proportion of carbohydrates. Fats can be satiating and deter overeating of carbohydrates. Overeating carbohydrates, especially refined and processed carbs, can raise triglycerides and reduce healthy HDL cholesterol.
Not having a balance of healthy carbohydrates and fats can increase the risk of chronic diseases such as heart disease and diabetes. A diet that includes healthy fats, lean proteins, and fibrous, nutrient dense carbohydrates is best.
Maintaining nerves and cell membranes
Fat is needed in nerve transmission.
Myelin is a coating around nerves throughout the body that is composed primarily of insulating fatty tissue. Without proper fat intake, the myelin may be compromised. This can interfere with efficient nerve stimulation and function.
Fat also helps maintain cell membranes, because lipids, or fats, make up most of the cell wall structure.
Which fats are healthful?
The key is to choose the right kind of fat and in the right quantities.
There are two main types of harmful dietary fat: saturated fats and trans fats.
Saturated fats are mainly of animal origin.
They increase levels of:
- total blood cholesterol
- low-density lipoprotein (LDL), or "bad" cholesterol
Coconut is a plant-based saturated fat.
Trans fats occur naturally in small quantities, but most trans fats in our diet result from partial hydrogenation, a food processing method.
Trans fats can increase LDL cholesterol, and they can reduce "good" high-density lipoprotein (HDL) cholesterol.
Both saturated and trans fats increase the risk of heart disease, but trans fats much more so. It is recommended that saturated fat makes up less than 10 percent of your total calories, but there is no recommended amount of trans fat in the diet. It is best to avoid trans fat.
Unsaturated and polyunsaturated fatty acids are healthful, in moderation.
They are thought to improve cholesterol levels and to reduce the risk of type 2 diabetes.
They usually come from plants, but omega 3 is a type of polyunsaturated fatty acid found in oily fish. It may be good for the heart.
Other good sources of omega 3 include flaxseed, walnuts, and soybeans.
Fats and weight gain
Fats need to be portioned out. Otherwise, weight gain is likely.
One gram of any fat contains 9 calories. That means about 252 calories per ounce since there are 28 grams in one ounce.
Since fats are very high in calories, they can produce a lot of energy. Even an apparently small portion can quickly add calories to a meal. However, it also means you can feel full on a smaller portion.
If fats are not portioned out, weight gain is likely. This increases the risk of heart disease, type 2 diabetes, and some types of cancer.
The Nurses' Health Study collected data for 42,000 men and women over 8 years. One investigation based on this data suggests that people who increased their consumption of saturated and trans fats gained weight, while those who increased consumption of healthy plant fats did not.
This could be because of the antioxidant effect of healthy dietary fats.
Replacing unhealthful fats with healthful fats
Unhealthful fats in our diet can come from:
- fatty meat
- butter, full-fat milk, and cheese
- ice cream
- processed snacks
For a more healthful option, replace these with:
- avocado, instead of mayonnaise, on salad
- lean meat or oily fish, such as salmon or mackerel
- peanut or almond butter
- natural, low-fat yogurt, low-fat milk, and cheese
- low-fat ice-cream, such as sorbets
- healthy snacks such as nuts and olives
Peanut butter and sorbets can still contain high amounts of sugar, and roasted nuts may contain other oils and additional salt.
Natural nuts are best for people with high blood pressure. It is a good idea to check the labels.
Tasty tips for a healthier fat intake
Here are some other tasty tips for reducing the intake of unhealthy fats and improving intake of healthy ones:
- Add sunflower seeds to a salad for extra crunch, and use olive oil and vinegar instead of ready-made salad dressing.
- Try bread or toast with natural peanut or almond butter instead of butter.
- Buy whole corn kernels and make popcorn at home. Put it in a pan with a cover and "air pop" it. There is no need for oil.
Not all fats are bad. Some increase risk of heart disease and other problems, but others are good for the health, and they are needed to absorb nutrients.
The key is to replace bad fats with good fats in the diet and not to let the fat-soluble nutrients go to waste.
The American Heart Association (AHA) has an interactive calculator that will tell you how much fat you need.