If we increase our food intake, we generally gain weight. Nutrition scientists can calculate the amount of weight gain that would be associated with a given increase in calories. In one study, 16 nonobese adults, aged 25 to 36 years, were fed 1000 calories per day in excess the calories needed to maintain a stable body weight. The subjects maintained this diet for 8 weeks, so they consumed a total of 56,000 extra calories. According to theory, 7700 extra calories will translate into a weight gain of 1 kilogram. Therefore, we expect each of these subjects to gain 56000/7700=7.3 kilograms. The weights in kilograms before and after the 8-week period are shown below:
ID: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Before: 55.7 54.9 59.6 62.3 74.2 75.6 70.7 53.3 73.3 63.4 68.1 73.7 91.7 55.9 61.7 57.8
After: 61.7 58.8 66.0 66.2 79.0 82.4 74.3 59.3 79.1 67.0 73.4 76.9 93.1 63.0 68.3 60.3
(1) For each subject, manually calculate the weight gain subtracting the weight before from the weight after.