What is good fat?
The basic chemistry of fat
The carboxyl group is the reactive center of a fatty acid. Whatever the fat does in our body, without the carboxyl group this would not work. It is the commando-center of the fatty acid.
There are also other parts in a fat's structure that define its chemical properties. They are within the carbon chain. And here is where good fat and bad fat is separated. The carbon atoms within the chain can be connected in different ways. The easiest type of chemical bonding is carbon atoms with a single bond like in the example above. However, sometimes there are also carbon atoms with a double bond. These types of fats are more reactive and can do several important jobs in our bodies besides only being fuel for our metabolism. They are also called unsaturated fats.
There are mono-unsaturated fatty acids with only one double-bond:
And there are poly-unsaturated fatty acids with more double-bonds:
With the type of chemical bonding come different properties that define if fat can bring us benefit or can do us harm.
One last point on chemistry, and then we go to the useful stuff. You might have heard the term Omega-3-fatty acids or Omega-6-fatty acids. The Omega carbon atom is just the last atom in the chain. In the last example above we have 18 carbon atoms. (one in the carboxyl group and 17 in the chain). The Omega atom is the carbon atom Nr.18 at the far left in the chain. Omega-"X" gives you the position of the first double bond. In the example of the poly-unsaturated fatty acid just above the first double bond is at the 6th ato when you start counting at the Omega atom, so it is an Omega-6-fatty acid. The example of the monounsaturated fatty above is an Omega-9-fatty acid...
OK, that is enough! You have done a great job staying with me and I promise no more chemistry now!
Good fat: Mono- and poly-unsaturated fats
Now that you know the basics of the chemistry of fat we can talk about good and bad fat. Good fat is generally unsaturated fat. Good fats are Omega-3, 6, and 9’s unsaturated fats. Why are they good?
Unsaturated fats have been found to lower LDL cholesterol, lower our blood pressure and fight inflammation in our body. A diet rich in good fats also decreases the risk of cardiovascular disease and stroke.
There are several types of fatty acids that are even essential for us as they cannot be synthesized within our body, compared to many other fatty acids. These are the alpha-linolenic-acid (an omega-3-fatty acid) and linoleic acid (an omega-6-fatty acid). These fatty acids are not only fuel to our body but they take over very important jobs. They are very important for the health of our heart, skin and brain. Without them we can develop for example dermatitis and scientists are currently researching their role in development of brain diseases like Alzheimer. As we are not able to build them on our own, we need to take care that we consume them with our nutrition.
The best sources of good fat are:
Sources of monounsaturated fat:
- Olive, canola, peanut, and sesame oils
- Nuts (almonds, peanuts, macadamia, hazelnuts, pecans, cashews)
- Peanut butter
Sources of polyunsaturated fat:
- Sunflower, sesame, and pumpkin seeds
- Fatty fish (salmon, tuna, mackerel, herring, trout, sardines) and fish oil
- Soybean and safflower oil
Bad fat: Saturated fats and trans-fat
On the other hand, there is bad fat. Archimedes once said "Poison is always a matter of dosage" Even water can be poisonous if you consume 15l of it! Bad fatty acids are fuel for our metabolism that can be stored in our fat tissue (just like good fat). However, if we consume too much of it, bad fat can do our body serious harm.
There are two kinds of bad fat. Unsaturated fats occur in natural food sources. These fats are built by saturated fatty acids. If you consume unsaturated fat in high amounts it can increase your LDL-cholesterol level and you have a higher risk or stroke and heart disease. You should limit the intake of unsaturated fat to 10% of your total calorie intake to stay on the safe side.
Sources of saturated fat:
- Red meat (beef, lamb, pork)
- Chicken skin
- Whole-fat dairy products (milk, cream, cheese)
- Ice cream
- Tropical oils such as coconut and palm oil
The worst kind of fat is trans-fat. These types of fats are found in processed food. With a chemical process called hydrogenation the properties of the natural double-bond is changed in a way, that unsaturated fat loses their beneficial properties and gets "very bad" instead. Don't worry. You will not find higehr amounts of bad unsaturated fat in natural products, they just occur in processed food.
Cis- and trans- gives you the structure of a carbon chain around a double bound. Cis- means that the chain builds a kind of a curve around the bond. This is commonly found in natural unsaturated fat. Trans- means the chain is flat and stretched. A flat chain is more easily packed into a structure. Such fats are often liquid and do not get rancid as fast as natural cis-fats. This is also the reason for food industry to do hydrogenation -> Higher shelf life -> Less reject -> More money!
Trans-fats significantly increase unhealthy LDL cholesterol, and they also decrease healthy HDL cholesterol. Moreover they increase inflammation, and insulin resistance. They can increase the risk of stroke, heart disease and diabetes. You should absolutely try to avoid them!
Sources of trans-fat:
- Commercially-baked pastries, cookies, doughnuts, muffins, cakes, pizza dough
- Packaged snack foods (crackers, microwave popcorn, chips)
- Stick margarine, vegetable shortening
- Fried foods (French fries, fried chicken, chicken nuggets, breaded fish)
- Anything containing hydrogenated or partially hydrogenated vegetable oil
Good fats & weight loss
Here comes the interesting part. How can fat help you with your weight loss? Fat has some good properties that can help you with your diet.
First, fat is filling. You can eat even small amounts of fat and feel full. Ever tried snacking nuts for example. They fill you up fast. However, be careful! They also contain a lot of calories. Dose fat wisely. Consider the total calories and try not do overdo. However, you will feel full earlier considering the calories that you consume. You can mix fat with fiber (e.g. avocados) to use this effect even better.
Fat tastes good. fat is savory and adds flavor to your food. You can add a little olive oil to your veggies and they will taste a lot better. Nobody wants to eat food without flavor. By adding healthy fats to your food you make it more enjoyable.
Fat adds balance. If you only consume carbs and fiber you will have a fast energy peak from carbs, but the energy will drop fast because carbs are processed by your body immediately. You will have less energy later during the day and you will feel hungry again. Fat makes you feel full longer and gives you long term energy. Diet is all about balance!
The bottom line
Reduce the amount of bad fat and increase the amount of good fat that you consume. You can use the lists in this article as a guideline on what to consume and what not.
Always consider the calories that you consume. Do not eat loads of good fat, but try to get a soft daily calorie deficit to lose weight. However, within your possible daily calorie intake add good fats to use their beneficial properties.
Good fat will make you feel full longer, you will enjoy your dishes more and you will be energized for a longer time and feel more balanced.