Fats 

You have no doubt heard that there are healthy and unhealthy fats.

That is not all there is to the story. You must also use each healthy fat a certain way to keep it healthy.

The Chemistry : 

Different fats are different hydrocarbons. They have different levels of saturation, meaning varying number of hydrogen atoms along the carbon chain. More hydrogen atoms makes the chain more saturated, solid and more stable to temperature.  Unsaturated fats are more liquid at a given temperature, and thus healthier, since they clog the arteries less.

For the same reason they also burn more easily. Burning oil generates unhealthy chemicals. Never heat an oil to the point of smoking. Use canola oil for high heat like sauteing, and olive for lower temps, or uncooked recipes like salad dressing.  

Worst fats: 

trans fats, hydrogenated fats, 

margarine and shortening

Better fats: 

Butter, Palm oil , Coconut Oil 

Best fats: 

Monounsaturated fats like 

Olive, especially cold pressed extra virgin,

regular and high heat canola oil, fats from raw nuts and avocado

Ideas: 

Dress salads with olive oil and vinegar

Dip breads in olive oil, balsamic vinegar and spices 

Dress oatmeal with a Tablespoon of olive oil

and good sprinkle of kosher salt

The FDA says “ "Limited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil.”