When talking about fat the mind instantly switches toward all the negative information regarding this critical macronutrient. Not only are fats needed in the diet but they are also NOT the source of which most people insidiously gain weight from. The general term “fat” is usually associated with meaty fat or oil that you see in dishes but “lipids” is a better term. Lipids are compounds that don’t dissolve in water and include oils, solid fats and waxy substances.
In the diet and body the most common form of lipids are fatty acids composed into triglycerides (or triacylglycerides “try-ah-seal-glis-er-ides” to be specific). Fatty acids can be saturated or unsaturated.
The following diagram shows a saturated fatty acid and an unsaturated fatty acid. (NB not scientifically correct in carbon number)
As you can see fatty acids are composed of a Carbon chain surrounded by Hydrogen atoms. A fatty acid is saturated when the chain only has single bonds as in the top picture. Saturated fatty acids are usually solid at room temperature and it is generally best to keep intake of these limited.
Unsaturated fatty acids occur when the chain has one or more double bonds in the carbon chain as seen on the bottom diagram. These are the “good” fats which have health benefits which will be discussed later.
Looking at the diagram above; the “α – alpha” and “ω – omega” indicate the two ends of a fatty acid chain. This is how the common naming of fatty acids originate. Naming occurs by counting how many carbon atoms in from the ω (omega) end of the chain the double bond occurs. In the above example this fatty acid would be an ω-4 fatty acid.
You will have heard of the two essential fatty acids ω-3 and ω-6.
ω-3 is also known as alpha-linolenic acid.
ω-6 is also known as linolenic acid.
Remember that “essential” means our bodies can’t produce this specific compound so we must obtain these from our diet.
Monounsaturated Fatty Acids (MUFA’s)
Come mostly from plant sources and include olive & sesame oils, almonds, pecans, cashews, peanuts and avocados and tend to be liquid at room temperature and solidify when cooled. These oils are stable and can be used for cooking.
Polyunsaturated Fatty Acids (PUFA’s)
ω-3 & ω-6 fatty acids are PUFA’s and remain liquid even when cooled. Because of their chemical structure they are highly reactive and should not be used for cooking as this may produce trans fats. These oils include corn, safflower, soy and sunflower oils.
Trans fats inhibit bodily functions such as the ones listed below and they promote weight gain. A person who consumes mainly trans fats in their diet will weigh more than someone whose diet is balanced even if their calorie intake is the same.
The modern diet heavily focuses on the ω-6 side of things but it’s best to focus the diet on the ω-3 side of the table in order to reap the basic benefits below.
Lipids play a vital role in
- body structures – keeping skin healthy and hair silky & shiny
- immune system functions preventing bacterial, viral and fungal infections
- form cell membranes
- production of hormone compounds for growth
- wound healing
- (ω-3) decreases blood clotting
- decreases risk of heart attack
- lowering blood triglycerides
- controlling chronic fatigue & anxiety
- thyroid balance (in combination with vitamin-A)
- preventing hypoglycaemia
- controlling gas and bloating
- liver support
ω-3 fatty acids may also assist in managing inflammation (of rheumatoid arthritis), behavioral disorders and mild cases of depression.
Along with triacylglycerides; other lipids in the body are phospholipids & cholesterol which also:
PROVIDE ENERGY – for every day activity (about ½ the energy used comes from fatty acids), endurance exercise or for short burst of intense activity.
STORED FOR ENERGY RESERVES – this is seen as the layer of body fat which the body has the ability to do so in a limitless capacity (hence why people become overweight). A fat cell can increase 50 times it’s original weight before reaching it’s limit where the body will synthesize new cells. Humans can survive up to a month only on fat reserves and adequate water supplies!
INSULATE AND PROTECT – we have a layer of fat just underneath the skin that helps regulate body temperature which is composed of triglycerides & fatty tissue surrounds and protects some organs such as the kidneys.
TRANSPORT FAT-SOLUBLE VITAMINS – by helping transport vitamins A, D, E and K through the small intestine wall and into the bloodstream. Without lipids in the diet we would become deficient in these vitamins.
Ensure you choose from the healthful list of foods above to reap the benefits of ω-3 fatty acids and do your best to restrict visible fat in meat and poultry products – which are saturated fatty acids. Avoiding trans fats (mostly found in deep fat fried foods & processed packaged foods in the form of hydrogenated oils) is also a good idea as their chemical structure is similar to saturated fats leading to all the negative effects thought of when consuming fat.
Cholesterol is produced by the body in enough quantities for bodily functions to occur so is not essential in the diet but enjoy them in moderation. Cholesterol, however, is important for producing testosterone & estrogen as well as the active form of vitamin-D (all important hormones for general growth, muscular hypertrophy, mood, bone strength & erectile function) & is the basis of bile acids – essential for fat digestion.
Men consume a higher amount of cholesterol than women so try to keep this in check to avoid elevated blood cholesterol levels.
Consuming 2 servings of fatty fish a week should help you reach your levels of ω-3 fatty acids. The higher caloric value of lipids will also mean you’ll feel fuller for longer as lipids are broken down and moved along the digestive tract slower than carbohydrates and protein. Therefore consuming a fatty meal before alcohol consumption will aid in keeping alcohol being absorbed rapidly.
Lipids don’t cause insulin release so blood sugar levels can be kept in check following meals higher in good fat – great for Type 2 diabetics. The lack of insulin will then stimulate fatty acids to be burned as fuel and less body fat being stored.
Fats! You can’t live without them, you CAN live, and enjoy them!
What favourite food source does your daily fat come from?
1 – Byrd-Bredbenner C., Berning, J., Beshgetoor, D., and Moe, G, Contemporary Nutrition – A Functional Approach, McGraw Hill, New York
2 – David Wolfe. “Superfoods: The Food and Medicine of the Future.”, North Atlantic Books, 2009
3 – Sally Fallon. “Eat Fat, Lose Fat.”, Hudson Street Press, 2005