With the rise of low fat products, you’d be forgiven for thinking that fat is the enemy. With constant reports toing and froing between fat being good for us and fat being bad for us, it’s understandable for us to not know what to do for the better. So, here’s the skinny on fat (pardon the pun).
What is dietary fat?
Fat is a source of energy. Fat provides us with 9kcal/g (compared with carbohydrates and protein which provide 4kcal/g). 99% of dietary fats are in the form of a triglyceride. A triglyceride is a chain of 3 fatty acids – which are made of carbon, hydrogen and oxygen – which is attached to one glycerol molecule. When we digest these fats, the body has to break down the bonds between the fatty acids and molecule in order for them to be absorbed in the intestine. Guidelines advise us to get no more than 30% of our daily calories from fat.
Types of fat
There are two main types of fat; saturated fat and unsaturated fat. Unsaturated fat can be broken down into other sub-types of fat known as monounsaturated fat and polyunsaturated fat.
Saturated fat is found mostly in animal products and some plants. Animal products include beef, beef fat, veal, pork, lard, poultry fat, butter, cream, milk, cheeses and other dairy products made from whole milk. Plant products include coconut oil, palm oil and palm kernel oil (also known as tropical oils), and cocoa butter. Saturated fat increases the LDL (bad) cholesterol and the amount of total cholesterol in the blood. This increases the risk of heart disease and diabetes. It is recommended to keep this type of fat to a minimum with the recommended daily allowance being no more than 10% of our daily calories.
Monounsaturated fat can be found in canola, olive oils, peanut oils and avocados. This type of fat lowers total cholesterol and LDL cholesterol and increases HDL (good) cholesterol. This lowers the incidence of heart disease. Research indicates that it may also lower blood pressure and reduce the inflammatory response. It is recommended to get no more than 12% of our daily calories from monounsaturated fat.
Polyunsaturated fat can be found in safflower, sesame and sunflower seeds, corn and soybeans, fish, fish oil, many nuts and seeds, and their oils. It is recommended that we get 7% of our daily calories from this type of fat.
Polyunsaturates contain a group of fats known as Essential Fatty Acids (EFA). These fatty acids are Omega 3 (Alpha Linolenic Acid or ALA) and Omega 6 (Linoleic Acid or LA). They are essential because our bodies cannot manufacture them so we need to get them from our diet. They are needed in our bodies to enable vital bodily functions.
Omega 3 sources:
- Flaxseeds and oil
- Hempseeds and oil
- Pumpkin seeds
- Brazil nuts
- Sesame seeds
- Some dark leafy green vegetables (kale, spinach, mustard greens, collards)
- Canola oil (cold-pressed and unrefined)
- Soybean oil
- Wheat germ oil
- Fresh tuna
Omega 6 sources:
- Flaxseeds and oil
- Hempseeds and oil
- Grapeseed oil
- Pumpkin seeds
- Pine nuts
- Pistachio nuts
- Sunflower seeds (raw)
- Olive oil
- Borage oil
- Evening primrose oil
- Black currant seed oil
- Chestnut oil
Essential fatty acids have the following effects on health:
- Prevents blood clots (anti-coagulant) and decreases the stickiness of blood
- Acts as an anti-inflammatory
- Lowers blood triglycerides
- Helps control blood pressure
- Lowers LDL and raises HDL
- Enhances transport of oxygen by red blood cells
- Enhances immune responsiveness
- Maintains the quality of cell membranes
- Essential for overall health and brain development
The brain is more than 60% structural fat and those used are high in Omega 3 fats. This shows why getting a good source of EFAs are required for cognitive function and mental health.
Signs of Fatty Acid imbalance are:
- Dry skin
- Frequent urination
- Attention deficit
- Soft nails
- Alligator skin
- Lowered immunity
- Dry, unmanageable hair
- Excessive thirst
- Brittle easily frayed nails
- “Chicken skin” on back of arms
- Dry eyes
- Learning problems
- Poor wound healing
- Frequent infections
- Patches of pale skin on cheeks
- Cracked skin on heels or fingertips
Trans fat is most commonly formed when an unsaturated oil (mono or poly) is blasted with hydrogen atoms at high temperature and pressure (also known as hydrogenated). This causes the fatty acid chains to change structure which causes the molecule to act more like a saturated fat. The majority of trans fats can be found in hard margarine, cookies, crackers, snack foods, fried foods (including fried fast food), doughnuts, pastries, baked goods and other processed foods made with or fried in partially hydrogenated oils.
Trans fats have the following health effects:
- Raise LDL cholesterol and lower HDL cholesterol
- Promotes the formation of arterial plaque which leads to circulation problems, high blood pressure, heart disease and stroke
- Decreases the response of human cells to insulin which can lead to type 2 diabetes and obesity
Trans fats should be used sparingly or avoided altogether. Trans fatty acids are not always listed on food ingredient labels. They may be listed as hydrogenated or partially hydrogenated oils so look out for these ingredients. They should make up <1% of your daily calories.
The bottom line
Rather than cutting fat out altogether, it is better to replace saturated fat with unsaturated fat. This can be done through reducing the intake of fast food, takeaways and sweet treats, using methods of cooking which use little or no fat such as boiling and grilling, swapping to reduced fat dairy products reducing processed and fatty meat and eating more fish, avocados, nuts, seeds and plant-based oils and spreads such as flaxseed oil. As previously stated, being deficient in fat can cause problems such as cognitive problems and lowered immunity so it is important to make sure that it is included but in moderation and in the right form.