Task: Question Answering
Input (English): Background Paragraph: Any unused energy in food—whether it comes from carbohydrates, proteins, or lipids—is stored in the body as fat. An extra 3,500 Calories of energy results in the storage of almost half a kilogram (1 pound) of stored body fat. People who consistently consume more food energy then they need may become obese. Obesity occurs when the body mass index is 30.0 kg/m 2 or greater. Body mass index (BMI) is an estimate of the fat content of the body. It is calculated by dividing a person’s weight (in kilograms) by the square of the person’s height (in meters). Obesity increases the risk of health problems such as type 2 diabetes and hypertension. 
Story: Greg wants to go on a diet. He decided it's time to make a change. He cut down on how much he eats every day and monitors his calorie intake, making sure that he is burning more calories that he is taking in. 
Question: Which is used to calculate BMI, weight in pounds or weight in kilograms?
Output (English): kilograms.