Final answer:
A dietary excess of carbohydrates, saturated fat, and cholesterol is responsible for obesity and heart disease due to their high caloric content and contribution to artery narrowing and atherosclerosis.
Step-by-step explanation:
Dietary excess of carbohydrates, saturated fat, and cholesterol can lead to several health complications, the most notable of which are obesity and heart disease. These dietary components, especially when consumed in excess, increase the body's fat storage due to their high caloric content. Excess fat storage, particularly in the form of saturated fat and cholesterol, contributes to narrowing of the arteries and can lead to atherosclerosis. Atherosclerosis is a condition that affects arterial blood flow and is strongly associated with cardiovascular diseases, including heart attacks and strokes. Furthermore, obesity, which is characterized by having a high percentage of body fat, can place an additional strain on the cardiovascular system and significantly increase one's risk for related diseases.
Conversely, diets that include an overabundance of these components do not lead to improve metabolism, enhance cognitive function, or increase bone density. In fact, excessive caloric intake, regardless of the source, can overwhelm the body's energy balance and lead to weight gain and metabolic disorders such as type 2 diabetes, in addition to cardiovascular problems.