On the non-fasting days, the intake consisted of an ordinary food mixture of proteids, fats, and carbohydrates, with a small addition of alcohol. The point to be emphasized here, however, is that the carbon-content was more than sufficient to meet the needs of the body. Thus, it will be observed that on all three of the days when food was taken, the income of carbon was far in excess of the output. In other words, on the day preceding the beginning of the fast the body stored up 135 grams of carbon, and on the day following the fast the body retained 169 grams of carbon to help make good the loss. Similarly, the amount of proteid food taken in on the day prior to the fast was considerably in excess of the needs of the body, 5.1 grams of nitrogen equivalent to 31.8 grams of proteid being stored for future use. Plainly, the man was not in either carbon or nitrogen balance prior to the fast, but was taking far more food than the needs of the body called for. This fact may be emphasized by noting that the total fuel value of the daily food, plus the fuel value of the alcohol, amounted on an average to about 4200 large calories, while the fuel value of the material metabolized on the feeding days averaged only 2500 calories. Looking at the figures showing the output of carbon, as well as of nitrogen, during the fasting days, it is to be seen that in the early days of fasting, the metabolism of the body tends to remain at a fairly constant level, especially when figured per kilogram of body-weight. To fully appreciate what takes place in a man of the above body-weight fasting for five days (though living on a large excess of food prior to the fast), the daily losses of carbon and nitrogen may be translated into terms of fat and proteid. If it is assumed that the total carbon, aside from what necessarily belongs to the proteid indicated by the nitrogen figures, comes from the oxidation of fat, it is easy to compute the amounts of fat and proteid metabolized, or destroyed, each day of the fasting period. These are shown in the following table: +------+--------------+--------------+ | Day. | Proteid | Fat | | | metabolized. | metabolized. | +------+--------------+--------------+ | | grams | grams | | 3 | 76.1 | 206.1 | | 4 | 80.3 | 191.6 | | 5 | 85.1 | 181.2 | | 6 | 85.6 | 177.6 | | 7 | 71.7 | 181.2 | +------+--------------+--------------+ Finally, if from these figures we calculate the fuel value of the proteid and fat oxidized per day, it is possible to gain a fairly clear conception of the part played by these two classes of tissue material during fasting, in furnishing the heat of the body and the energy for muscular motion, etc.