1 gram of fat equals approximately 9 calories.
Food sources of fat contain a combination of 3 types of fats in different ratios:
- Saturated fat (solid at room temperature)
- Unsaturated fats (liquid at room temperature)
There is also another type of fat, called trans-fat, which is mainly the product of processing vegetable oils.
We refer to fat type such as saturated fat, as fats that consist mostly of saturated fats. This does not mean that other types of fats are absent. For instance, one ounce of coconut oil has 24.2g of saturated fat, 1.6g of monounsaturated fat and 0.5g of polyunsaturated fat. It also contains 504mg of omega-6 fatty acids and no omega-3 fatty acids.
What fats are good and what fats are bad? (1)
In summary, saturated fats, monounsaturated fats and some polyunsaturated fats in the correct ratio are healthy fats.
Unhealthy fats come from processed vegetables oils and trans-fats. Additionally, a high ratio of omega 6 to omega 3 fatty acids is also not recommended.
Saturated fats received a bad name in the late 1970s when the U.S. government implemented the first dietary guidelines (1977), promoting a high carbohydrate and a low fat diet.
These guidelines were based on a controversial hypothesis, which stated that dietary saturated fat increases blood cholesterol levels and, therefore, leads to cardiovascular diseases, which at the time was a major concern.
To this day, this hypothesis has not been actually proven by clinical trials.
From the moment that these guidelines were implemented, a sudden rise in obesity rates occurred, and they have been increasing ever since. Many scientists blame it on the increase of carbohydrates in our diets rather than on a diet high in saturated fats. (2, 3)
Current scientific evidence shows that saturated fats do not cause obesity, diabetes or cardiovascular diseases and the focus of the investigation should rather turn to the current recommendations of high carbohydrate diets. (2, 4)
The bottom line is that saturated fat is safe.
Polyunsaturated fats include both beneficial and harmful fats in various ratios. Omega 3 fatty acids have great anti-inflammatory and antioxidant properties while Omega 6 fatty acids have pro-inflammatory properties.
Studies show that a diet with a high ratio of Omega-6 to Omega-3 fatty acids lead to an increased risk of diabetes, obesity, hypertension, cardiovascular disease and insulin resistance.
Here are some examples of ratios of omega 6 to omega 3 fatty acids: (1)
Mesolithic men: between 1-4 to 1;
Current European diet: between 10-14 to 1;
Other Western diets: between 15-17 to 1 (5);
Israel Jewish population: between 22-26 to 1 (high occurrence of obesity, cardiovascular disease, hypertension and type 2 diabetes).
Lower ratios of omega 6 to omega 3 fatty acids have been shown to have positive health effects (5):
Ratio 2.5 to 1 – reduction in the increasing rectal cells in colorectal cancer patients
Ratio between 2 and 3 to 1 – stopped inflammation in rheumatoid arthritis sufferers
Ratio 5 to 1 – showed improvements in asthma symptoms
Ratio 10 to 1 – presented negative health effects, associated with inflammation.
All scientists agree that monounsaturated fats are the good fats.
The controversy relates to saturated fats, mainly because of the above-mentioned guidelines, and polyunsaturated fats.
Trans fats and partially hydrogenated oils (PHOs)
There are two types of trans- fats acids (6):
- The naturally occurring trans- fat, produced in the guts of some animals. Tiny amounts may exist in dairy and milk products.
- The artificially created trans- fat, produced by adding hydrogen to vegetable oils, in order to make it more solid. These are known as PHOs.
The biggest dietary sources of trans- fats are PHOs.
A diet high in trans- fatty acids raises the bad cholesterol (LDL), lowers the good cholesterol (HDL) and increases the risk of cardiovascular diseases, stroke and type 2 diabetes.
For better health your diet should include more omega 3 fatty acids, monounsaturated fats and saturated fats in moderation. Saturated fats should be eaten in moderation because since we have a physical limitation of how much we can eat, we need to make some choices. Foods containing the healthiest oils such as small cold water fish, walnuts, chia seeds and flaxseeds and cold press oils such as flaxseed oil and extra virgin olive oil are high in energy and very satiating. Having too much of any other fats will reduce the intake of the fats that are proven to be the most beneficial.
NOTE: Although chia seeds and flaxseeds oils are considered beneficial, they contain mostly alpha linolenic acid which is not as health-promoting as was previously believed.
Avoid trans- fats and any processed fats especially vegetable oils and margarines.