Because of a loss of the above-mentioned muscle mass, there is a decline in metabolism. This leads to less energy being released and being used. This excess of energy is getting stored in the body in the form of body fat.
An increase in body fat has a couple of negative side effects for elderly people, e.g. increase in the lipid profile, with more LDL-cholesterol. It also leads to an increase in blood pressure and an increased change for heart disease and diabetes.