Which of the following nutrients does not provide energy?

Correct Answer: D

Rationale: Proteins, carbohydrates, and fats are macronutrients that provide energy in the form of calories when consumed and metabolized by the body. Each gram of protein or carbohydrate provides about 4 calories, and each gram of fat provides about 9 calories. On the other hand, vitamins do not provide energy or calories. They are micronutrients that are essential for various biochemical and physiological processes in the body, including the metabolism of macronutrients. However, they do not contribute directly to the energy supply. Therefore, the correct answer is 'D: Vitamins'. Choices A, B, and C (Proteins, Carbohydrates, and Fats) are incorrect because they are macronutrients that do provide energy/calories when metabolized.

Correct Answer: B

Rationale: The correct answer is B: 7 kcal/g. Alcohol provides approximately 7 kilocalories per gram, making it a significant source of energy or 'empty calories' in the diet that do not contain any nutrients. 'Empty calories' refer to the calorie content without the presence of essential nutrients. Choices A, C, and D are incorrect. The energy values of 3 kcal/g, 10 kcal/g, and 25 kcal/g are not accurate for alcohol; instead, they may pertain to other nutrients such as carbohydrates (approximately 4 kcal/g), fats (approximately 9 kcal/g), and oils (approximately 9 kcal/g).

Correct Answer: D

Rationale: The correct answer is D. Polyunsaturated fatty acids. Polyunsaturated fatty acids have two or more double bonds in their carbon chains, making them less stable and more prone to oxidation. This characteristic distinguishes them from saturated fatty acids (Choice A), which have single bonds between carbon atoms providing stability. Monounsaturated fatty acids (Choice B) contain only one double bond, and trans fatty acids (Choice C) can have varying numbers of double bonds but are not specifically defined by having two or more double bonds.

Correct Answer: C

Rationale: One pound of body fat is equivalent to approximately 3500 calories. This is a generally accepted caloric value used in nutrition and weight management. It's important to note that this is an estimation and individual variations may occur. Choice A (1500 calories), Choice B (2500 calories), and Choice D (5000 calories) are incorrect because they do not match the generally accepted caloric value of 3500 calories for one pound of body fat.

Correct Answer: C

Rationale: The correct answer is 1500 mg to 3000 mg per day. This is the level of sodium restriction typically recommended for heart failure patients. It helps manage fluid retention and reduce blood pressure, which are both crucial in treating heart failure. A sodium intake of less than 500 mg per day (Choice A) might be too restrictive and is not typically recommended. Similarly, an intake of 1000 mg to 1500 mg per day (Choice B) falls short of the recommended range. Lastly, an intake of 3000 to 3500 mg per day (Choice D) exceeds the recommended upper limit, potentially exacerbating fluid retention and high blood pressure.