Fats and oils are triglycerides. The standard formula is three carbon atoms, which is a glycerol, from which are attached various forms of fatty acids. Fats are triglycerides that are usually solids at room temperature, while oils are tiglycerides that are liquids at room temperature. Fats and oils are immiscible with water, due to their organic chemical composition, hence the old saying "oil and water do not mix". The importance of triglycerides to the human diet are numerous, there are some amino acids and enzymes that can not be obtained from proteins and carbohydrates alone. Some fat has to be included in the dietary consideration, but it should be closely monitored and not allowed to mass on the body as excess energy, which the body stores efficiently as new adipose tissue. Adipose cells are typically what we call "fat" deposits on the body. Too much fat on the body and in the blood can lead to heart diseases such as atherosclerosis, or "hardening of the arteries".