Correct Answer: D

Rationale: The correct answer is D: Increased awareness of personal food patterns. Keeping a food record is beneficial as it helps individuals become more mindful of their eating habits and food choices. This awareness can lead to identifying patterns, triggers, and areas for improvement in one's diet. Choices A, B, and C are incorrect because the primary benefit of keeping a food record is not about precise estimates of portion sizes, determining energy intake, or estimating supplement needs, but rather about developing a deeper understanding of personal food patterns.

Correct Answer: A

Rationale: Carbohydrates are the body's primary source of energy. When carbohydrates are consumed, they are broken down into glucose, which is used by the body's cells for energy production. Fats and proteins are also essential nutrients, but carbohydrates are the preferred energy source for the body due to their quick conversion into fuel. Vitamins are not a direct source of energy but play crucial roles in various bodily functions.

Correct Answer: A

Rationale: The correct answer is A: prevention and control of chronic diseases. In this century, nutritional recommendations have increasingly emphasized the importance of preventing and managing chronic diseases like obesity, diabetes, cardiovascular diseases, and cancer. Lifestyle factors such as diet play a significant role in the development of these conditions. Option B, improved sanitation and public health, although important for overall health, is not the primary focus of nutritional recommendations. Option C, prevention and control of infectious diseases, is also crucial but does not reflect the current major focus of nutritional recommendations. Option D, development of healthful foods using food technology, is a valid area of interest but is not the primary shift in focus observed in nutritional recommendations.

Correct Answer: A

Rationale: The correct answer is A: provide energy. Nutrients play a crucial role in providing energy for the body's various functions. While they do help in regulating metabolic processes and in building and repairing tissue, the primary function related to energy production. Choices B, C, and D are incorrect as nutrients are not primarily responsible for controlling cellular wastes, hormone levels, or absorption.

Correct Answer: C

Rationale: Protein provides 4 kcal per gram. Therefore, 15 grams of protein will provide 15 grams x 4 kcal/gram = 60 kcal. Choices A, B, and D are incorrect because they do not consider the caloric value of protein correctly.