In the context of energy balance and weight change, approximately how many kilocalories (Calories) are stored in 1 pound (lb) of human body fat?

• A. About 7,000 kilocalories (kcal)
• B. About 500 kilocalories (kcal)
• C. About 1,000 kilocalories (kcal)
• D. About 3,500 kilocalories (kcal)

Answer: (D)

Verified step by step guidance

1. Understand that body fat stores energy, and this energy can be measured in kilocalories (kcal), which are commonly referred to as Calories in nutrition.
2. Recognize that when discussing weight change, especially fat loss or gain, the energy content of fat tissue is a key factor in calculating how many kilocalories correspond to a certain amount of body fat.
3. Recall the widely accepted estimate in nutrition science that 1 pound (lb) of human body fat stores approximately 3,500 kilocalories (kcal). This value is derived from the energy density of fat tissue, which is about 9 kcal per gram of pure fat, adjusted for the fact that body fat tissue is not 100% fat.
4. Note that this 3,500 kcal per pound figure is used as a rule of thumb to estimate how changes in energy intake or expenditure translate into changes in body weight over time.
5. Therefore, the approximate energy stored in 1 pound of human body fat is about 3,500 kilocalories (kcal), which helps explain why a deficit or surplus of this amount of energy typically results in a loss or gain of one pound of body fat.