There are many factors that increase the occurrence of cardiovascular disease.
Two of these are smoking and uncontrolled diabetes. Nicotine is now universally recognized to be a chemical that constricts blood vessels, this strains the heart as more effort is required to pump blood through the body. In addition, gases like carbon monoxide that are inhaled when a person smokes reduce the oxygen carrying capacity of blood. To satisfy the oxygen requirements of the body the heart has to now beat harder and the number of heart beats is also increased. Uncontrolled diabetes leads to the creation of excessive cholesterol and layers of fat along blood vessels. These strain the heart in a manner similar to that when a person smokes.
One dietary approach to reducing the risk of cardiovascular disease is to restrict the number of total calories consumed, particularly those in the form of saturated and trans fats. If a person consumes more calories than what is burnt, the excess calories are converted to fat by the body and stored for future use. This makes it harder for the heart to pump blood through blood vessels and increases the risk of cardiovascular diseases.