Answer: The correct answer is: B. add nutrient-dense, healthy sources of energy to his diet, including fatty fish, whole-grain cereals, nuts, peanut butter, and olive oil.
Explanation: This option is the best choice because it contains a variety of foods through which Dennis can obtain all the macro nutrients needed for optimal health and functioning. This diet is especially high in protein and healthy fats, which combined with his exercise regimen, will help Dennis gain weight in the form of lean tissue. Options A and C are incorrect because they involve supplementation which is unnecessary since Dennis can obtain all the nutrients he needs through his well balanced diet alone. Option D is incorrect since high levels of saturated fat are harmful to a person's health.