Final answer:
A healthy diet can reduce the risk of stroke, heart disease, hypertension, and type 2 diabetes. Type 1 diabetes cannot be prevented through diet, unlike Type 2 diabetes, which can.
Step-by-step explanation:
A healthy diet can lower the risk of several noninfectious diseases. Heart disease, stroke, and type 2 diabetes are among the most common chronic diseases that are largely preventable with lifestyle changes, including healthy eating habits. While Type 1 diabetes is not preventable as it is an autoimmune disease, Type 2 diabetes is largely influenced by diet and exercise. Obesity, being a significant risk factor for many diseases, can be mitigated through a diet that promotes a healthy weight.
Furthermore, healthy eating can also positively impact mental health and cognitive function, potentially reducing the risks of dementia. Contrarily, a healthier diet does not have a marked impact on conditions such as ear infections, lupus, or skin cancer which are influenced by factors other than diet.
Therefore, the correct answer to the question about which diseases a healthy diet can reduce the risk of is 5) Stroke, heart disease, hypertension, and type 2 diabetes.