This topic was requested by John who wanted some clarification about the difference between fat and cholesterol, and why some foods are high in cholesterol, but not in fat. 

Cholesterol is like fat, but it is not fat. It performs different functions in the body, both good and bad. There is cholesterol in every cell in the body, and also in some hormones. One of its functions is that it helps the body digest and absorb fat.  Also, in sunlight, cholesterol in the skin is converted to vitamin D. 

There are two different types of cholesterol: the kind found in the blood and the kind found in food. Some of the cholesterol found in blood is produced by the body. If the body produces too much, the risk of heart disease increases. Extra cholesterol produced by the body is either changed into body fat or it can build up in the arteries.

The cholesterol in food exists only in those made from animals (meat, fish, poultry, dairy, eggs). Eating a large amount of dietary cholesterol could increase blood cholesterol , but some people are more sensitive to the cholesterol in foods than others. Cholesterol in food does not automatically become blood cholesterol. Intake of fat in food has more of an effect on blood cholesterol than does the cholesterol in food. Specifically, foods that are high in saturated fat cause an increase in bad (LDL) cholesterol. Some foods are very high in cholesterol, yet very low in saturated fat. These foods include crab and shrimp, and are much less likely to increase blood cholesterol than foods that are high in saturated fat such as fatty cuts of beef, butter and cheesecake.

Duyff, L. D. The American Dietetic Association’s Complete Food & Nutrition Guide, 1998.