Final answer:
To convert from kilocalories to watts, we calculate the total daily energy intake in joules and then divide by the number of seconds in a day to get power in watts. An intake of 2000 kcal/day approximately equals 100 watts, after considering caloric variability.
Step-by-step explanation:
To convert the energy content of a daily human diet from kilocalories to watts, we use the conversion between kilocalories and joules, and then calculate the power in watts based on the energy consumption per day. One kilocalorie (kcal) is equivalent to 4186 joules (J). A diet of 2000 kcal/day is equivalent to 2000 × 4186 J = 8.372 × 106 J (or 8.372 megajoules).
Power is defined as energy per unit time, and the standard unit of power is the watt (W), which is equivalent to one joule per second. To find the average power consumption in watts, we divide the daily energy consumption in joules by the number of seconds in a day. There are 86,400 seconds in one day, so the average power is 8.372 × 106 J / 86,400 s, which comes out to approximately 96.85 W.
For the purposes of this calculation, and given the variability in actual daily caloric intake, it is common to use a rounded-off value. Hence, it is reasonable to approximate the average daily human diet power consumption as 100 watts.