by Yvette Brazier | Reviewed by Natalie Olsen, RD, LD, ACSM EP-C | People often seek to avoid fats when they want to lose weight, but not all fats are bad, and we need some fats to stay healthy.
Plant-based fats such as olive oil, for example, are rich in antioxidants and may be powerful cancer fighters. Without fats, the body cannot absorb some necessary nutrients.
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.
Fast facts about fats
- 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
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
- depression
- 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.
The average American adult gets around 33 percent of their calories from fat. Much of the fat in the American diet comes from animal fat.
An excess of animal fat has been linked to higher rates of heart and cardiovascular disease, high cholesterol levels, diabetes, obesity, and cancer, to name a few.
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.
Absorbing nutrients
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.
Unhealthful fats
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.
Healthful fats
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.
