When you eat fats they are broken down in the small intestine like other foods; however, they can’t be digested like other nutrients. Simply put the blood is mostly water and the fats are mostly oil and everyone knows that oil and water do not mix. Your body has devised a very clever way of getting fat to mix in the blood. It produces different proteins that surround the fats and let them flow in the blood. These proteins mixed with lipids or fats are called lipoproteins. There are basically four of them classified by their size. Remember that oil floats on water therefore lipids are less dense than the blood. That means the larger the lipoprotein the less dense it is.
The largest lipoproteins are the chylomicrons. These are little protein balloons that circulate in the blood. As they pass cells that need some fat they give it to them. When they are empty the liver recycles them. The chylomicrons carry fat from your diet in the blood.
The next largest are the very low density lipoproteins. VLDL. These carry fats produced in the liver usually from excess sugar, alcohol, or protein. They also carry cholesterol. The cholesterol is also needed by the cells. As they circulate and the cells use cholesterol and fat from them they shrink and become low density lipoproteins.
Low Density Lipoprotein or as Dr. Len Kravits form the University of New Mexico calls them Lousy Density Lipoproteins. These particles are tiny and are full of leftover cholesterol. They can get stuck between cells and cause damage which is how they contribute to hardening of the arteries. If the level of them does not get to high they are recycled by the liver. Note that these are not produced from eating to much fat but from carbohydrates, alcohol, and protein amounts above the levels you need to maintain your calorie needs. In other words they are from overeating.
Finally the High Density Lipoproteins of as Dr Kravits calls them Healthy Density Lipoproteins. These particles carry unneeded cholesterol from the cells back to the liver to be processed. They are the good guys.
I hope this makes some sense. It really is needed to understand what types of fats you should eat.