For many years, dietary fat was demonised and people started consuming more processed, sugar-laden foods. As a result, people became sick and overweight, and the rates of metabolic diseases such as diabetes and heart disease escalated (1). We now know that moderate intake of healthy fat is an important part of our diet, and even saturated fat isn’t as bad as it was made out to be. But what is dietary fat and why is it so important?
WHAT IS DIETARY FAT?
Fat is a macronutrient in food (the others are Carbohydrate and Protein). Based on the chemical structure, fats take different forms such as saturated, monounsaturated and polyunsaturated fats.
Saturated Fats (SFAs)
Saturated fats are most commonly found in animal products, and play a role in heart health, brain health, skin health, immune health and even weight loss (2). Some examples include butter, coconut oil and the fat in meats such as beef, lamb and pork.
Monounsaturated Fats (MUFAs)
The predominant fat in the famous “Mediterranean diet”. MUFAS, are known for their role in decreased breast cancer risk, regulation of blood cholesterol levels, reduced body fat and reduced risk of heart disease (3). Almonds, avocado and eggs are examples of foods that contain MUFAs.
Polyunsaturated Fats (PUFAs: Omega-3 and Omega-6)
Polyunsaturated Fats include two essential Fatty Acids that we need from our diet: Omega-3 and Omega-6 Fatty Acids. OMEGA-3 fatty acids are known for their health benefits including brain and heart health, reduction in symptoms of depression, anxiety and ADHD, anti-inflammatory properties (4), joint health and cancer fighting properties. Some foods that contain Omega-3 fatty acids are fatty fish such as salmon and grass-fed beef. OMEGA-6 fatty acids are also important for brain development, immune system function and blood pressure regulation. Pumpkin seeds, chia seeds, flaxseeds and nuts are rich, healthy sources of Omega-6 fatty acids. Vegetable oils used for cooking and in processed foods are also high in Omega-6. Whilst they are both essential, in nature, humans would consume them in a ratio of around 1:1 Omega-6 to Omega-3. However, with the introduction of vegetable oils for cooking, a typical western diet includes up to 25 times more Omega-6 Fatty acids. This creates a pro-inflammatory state in the body, and inflammation is one of the leading causes of metabolic diseases such as heart disease and diabetes (5, 6). So, to keep it simple, whilst it is ok to consume whole foods containing Omega-6 Fatty Acids, we should mostly avoid refined and processed vegetable oils.
WHY DO YOU NEED FAT IN YOUR DIET?
- Improves the uptake of fat-soluble vitamins A, D, E and K
- Helps maintain skin health
- Helps maintain healthy joint function
- Provides fuel/energy for the body and supports cell growth and structure
- Helps transport nutrients across cell membranes
- Essential for optimal nerve, brain and heart function
- The human brain is nearly 60% fat and fatty acids are critical for cognitive performance
- Helps maintain hormone balance, and sex drive!! (remember dietary cholesterol, found in fat, is the building blocks of hormones)
- Can help maintain a stable weight, and help you to get leaner
ARE THERE FATS TO AVOID?
Trans fats are a by-product of a process called hydrogenation which turns liquid vegetable oils into solids and prevents them from becoming rancid. Essentially, it turns a non-saturated fat into an unhealthy, and unnatural version of a saturated fat. Like most things, when we mess with nature, we mess things up! Trans fats create inflammation in the body, increase the more harmful LDL cholesterol and reduce the beneficial HDL cholesterol. Basically, these man-made fats are bad news!
TAKE HOME MESSAGE
Naturally occurring, unrefined dietary fats are an essential and healthy part of a balanced diet. Include a variety of SFAs, MUFAs and PUFAs in your diet for optimal health. Enjoy the following foods in moderation:
- Nuts and seeds
- Full fat dairy in moderation
- Fatty Fish such as Salmon, Mackerel, Sardines and Herring
- Lean beef, pork and lamb meat and offal
- Game meats
- Olives and extra-virgin olive oil
For better health, avoid processed and refined “junk foods” that are a source of trans fats and Omega-6 in the form of vegetable oils, and usually sugar and other refined carbohydrates.