Just like carbs, fats are a source of energy, whereas proteins are building material. Protein is only used as a source of energy in certain cases. In the past, most people believed fats to be ‘evil’. Many people basically believed fat makes you fat. Bodybuilders were all into low-fat diets. Luckily, we know more today. Fats are not strictly bad at all. In fact, it’s quite the opposite.
Some types of fats are even essential, that means they can not be built by the human body itself. These are called essential fatty acids, often simply referred to as ‘EFAs’. These consist of omega-3 and omega-6 fatty acids. EFAs are involved in numerous processes in the human body and have various effects on the cardiovascular, reproductive, immune and nervous system. As most people’s food choices in western countries are very bad, it is no miracle that a lot of people here suffer from EFA deficiency, which is linked to several serious health conditions, like obesity, diabetes, cancer, immune disfunction or depression.
However, there are two things you should know.
First, you need to understand that any nutrient will lead to excess weight if you eat too much of it. No single nutrient is ‘evil’ and justly the scapegoat for obesity, nor is any specific nutrient all good and healthy. If you eat too many calories, you’ll end up being overweight. It does not matter, where these calories come from. Even if they come from the ‘healthiest’ foods, if you eat too much, those calories will be stored as body fat. If you eat too much, you’ll weigh to much. It’s as simple as that. So please remember: moderation is key!
Second, you should generally avoid processed foods and junk food. Basically, fats from these foods are no good at all.
When it comes to health and nutrition, I have a very practical mind. I always try to take a sensible approach. So let’s focus on the important part. Which sources of fats are good? Which foods are rich in good fats? So what can we eat?
Fish and shellfish are an excellent source of fats. Tuna, salmon, trout.. fish are rich in essential fatty acids. Usually, however, one serving of fish doesn’t contain enough fat. Fish is a great food and a perfect source of protein, though. To still get the benefits of the essential fatty acids found in fish, you can use high quality fish oil products like Optimal Omega Fish Oil:
Health Direct Optimal Omega HP Fish Oil, 90 Softgels
Nuts and seeds are also a great source of fats. Peanuts, walnuts, hazelnuts, cashew kernels, pumpkin seeds, sunflower seeds.. are all rich in fats. The nut containing the most fat ist the macadamia nut (75% fat).
There are also fruits which contain larger amounts of fats, like avocados and olives. These are perfect sources of fat, plus, they are a great alternative to nuts and seeds. If you’d like to try more exotic fruits, try durians. 100g of durians contain about 20g of fats.
Durians. Fancy fruits. (Photo by Jim Hafiz)
There’s another relatively exotic type of fat source that I personally like a lot: coconuts! The saturated fats found in coconuts have a unique structure and unique properties. Unlike other saturated fats, the fats from coconuts are mainly used as a source of energy instead of being stored as body fat. If you’d replace a certain amount of other fats with fats from coconuts over a longer period of time, you’d most probably lose weight. I’ve read about many people who replaced the usual oils in their diet with virgin coconut oil. As a result, these people lost weight, felt less hungry and experienced increased energy levels. I really believe that there will be quite more talk about this pretty much forgotten food and its beneficial effects in the future. You can get excellent virgin coconut oil here:
Nature's Way Organic Coconut Oil, 16 Oz.
I hope I listed the best sources of fats here. You should now hopefully be able to supply your body with all the healthy fats it needs. I appreciate your feedback a lot, so please leave me a comment and tell me what you think. Did I forget about certain foods? What’s your favorite source of healthy fats? Got questions? Be free to ask me any questions and tell me what you think. 
Further, you can find a list with nutrition facts for different foods rich in unsaturated, healthy fats here.
You forgot grass fed beef.