Fat digestion is a bit different than carbohydrate and protein digestion in that there are several processes that can occur in the digestion of fats.  The goal of fat digestion is to dismantle triglycerides into small molecules that the body can absorb and use.  Typically these are monoglycerides, fatty acids, and glycerol.

Digestion of fats....

Fat begins digestion in the mouth.  Some hard fats begin to melt when they reach body temperature.  The salivary glands at the base of the toungue release a lipase enzyme that digests a small amount of fat in adults but in children this enzyme very efficiently digests the short and medium chain fatty acids found in milk.  

On to the stomach

Fat does not do much in the stomach except float around in a layer above the components of other food.  Very little fat digestion takes place here.  The stomach is just a temporary way station for fat.  

To the small intestine

Fat enters the small intestine and a hormone is released that signals the gallbladdeer to release its stores of bile.  Remember that bile is produced in the liver from cholesterol that was carried there by HDL.  Bile is an emulsifier which simply allows the fat to mix with water.  Then the fats can be digested by the lipase enzymes from the pancreas.  According to some researchers, when you consider how fat is digested you can see the argument for food combining.

Into the blood

Not all fat that has been digested can move into the bloodstream.  Small units of fat (Glycerol and short- and medium- chain fatty acids) that have been emulsified in the small intestine, can diffuse easily into the intestinal cells.  They are absorbed directly into the bloodstream. 

Once in the bloodstream, the glycerol and fatty acids travel throughout the body to provide energy, insulate against temperature extremes, protect against shock, and build cell structures.  The energy to make a muscle contract (even the heart) is supplied mostly from fat so triglycerides are constantly needed in the system.  This fat is provided from the intestines as we have just discussed or from the adipose tissue where fat has been stored.  

What about the rest of the fat?

The rest of the fat in the small intestine are the mono-glycerides and the long chain fatty acids.  These fats are required to take another route due to their size.  They merge with spherical complexes called micelles.  The micelles now diffuse into the intesinal cells and the monoglycerides and the long chain fatty acids are then reassembled into triglycerides.