Fats are a necessary part of every diet. In fact, 60% of the brain is comprised of fat! Certain fats are necessary in the daily diet for optimal energy, clarity of thought and even weight loss. To decipher the good fats from the bad, it is important to understand their critical differences.

Fats are composed of building blocks called fatty acids. There are four major categories of fats:

• Saturated fats
• Polyunsaturated fats
• Monounsaturated fats
• Essential fatty acids

These categories are based on the number of hydrogen atoms in the chemical structure of a molecule of fatty acid.

Unlike proteins and carbohydrates, which yield four calories per gram, 1 gram of fat yields nine calories. The following calculation demonstrates the amount consumed in a diet comprised of 30% fat:

If an adult consumes 1,800 calories per day the calculation would be:

1,800 (calories) x 0.3 (30%) divided by 9 (calories per gram) = 60 grams of fat

Saturated fats
Saturated fats are known as the “bad fats”. They are found mostly in animal products, dairy items (cream, whole milk) and tropical oils such as coconut, palm and palm kernel oil. The liver uses saturated fats to produce cholesterol. Excessive consumption of saturated fats can raise the level of the “bad cholesterol” known as low-density lipoprotein (LDL). Although cholesterol plays a vital role in our bodies, such as maintaining proper structure of our cell walls, production of the sex hormones estrogen and testosterone and the adrenal hormone cortisol, an increase in the amount of cholesterol we produce can also have detrimental effects on blood flow. Eating large amounts of saturated fat increases the level of LDL in our system, causing damage such as stiffening and narrowing of the arterial walls. Damage to the arterial walls increases the risk of cardiovascular disease, heart attack, stroke and other vascular disturbances. It is important to keep these fats to a minimum in the diet.

Polyunsaturated fats
Polyunsaturated fats (PUFAs) are the second category of fat. They are found in most vegetable oils such as soybean, corn, safflower and sunflower oils. Although these fats have the positive effect of lowering your “bad cholesterol” (LDL), they also lower your “good cholesterol”, called high-density lipoprotein (HDL). PUFAs also create an imbalance in the ratio of omega-6 essential fatty acids to omega-3 essential fatty acids. This imbalance can alter hormones called prostaglandins in the body. Prostaglandins derived from omega-6 essential fatty acids promote inflammation, cell proliferation and blood clotting, while prostaglandins derived from omega-3 fatty acids promote the opposite effects. While both effects are necessary for the body to run smoothly, eating too many PUFAs can increase levels of omega-6 fatty acids, causing inflammatory reactions and exacerbation of autoimmune conditions (e.g. Crohn’s, colitis and arthritis).

Monounsaturated fats
Monounsaturated fats are known as the “good fats”. They are found in olive, canola and peanut oils and in avocados. These fats appear to lower “bad cholesterol” (LDL) and have minimal or no effect on the “good cholesterol” (HDL). Olive oil contains the highest amount of monounsaturated fats of all the edible oils. The best type of olive oil to buy is that labeled “extra-virgin”, made from the first pressing of the olives. This oil is very flavorful and can be used for cooking or in salad dressings. All oils should be stored in dark, cool places.

Essential fatty acids
Essential fatty acids are vital for health and cannot be produced by the body. Every living cell in the body needs essential fatty acids to rebuild and produce new cells. Essential fatty acids and their derivatives are responsible for prostaglandin synthesis, immune system function, neural development, energy production and anti-inflammatory responses. There are two basic categories of essential fatty acids:

1) Omega-3 fatty acids called alpha-linolenic acid
2) Omega-6 fatty acids called linoleic acid

The balance of omega-6 to omega-3 is very important and has a teeter-totter sort of effect; if we get too much of one kind, we will become deficient in the other. Most people living in North America have too much omega-6 in their diets and too little omega-3. Omega-3 fatty acids are found in flaxseed oil, deepwater fish and fish oil, walnuts and walnut oil and soybeans. Omega-6 is found primarily in raw nuts, seeds, legumes, borage oil, grapeseed oil and primrose oil. As recommended above, to reduce the production of omega-6 fatty acids, decrease the amount of the polyunsaturated vegetable oils in your diet. To increase levels of omega-3 fatty acids,

One other type of fats that must be mentioned is trans-fatty acids (TFAs). Trans-fatty acids are produced when polyunsaturated oils are hydrogenated to make them into solid foods. This process involves heating the oil to an extremely high temperature, creating a hard, spreadable substance like margarine or vegetable shortening. Trans-fatty acids increase the production of LDL and decrease the production of HDL. They are bad for your heart and cause hardening and narrowing of the arteries. In addition, when polyunsaturated fats are heated to high temperatures, they release free radicals which are precursors to cancer-causing agents in your body. It is best to avoid trans-fatty acids in your diet. Check food labels carefully—if you see the words “partially hydrogenated oils”, move on, this product contains trans-fatty acids.