9.1. The range of adaptation

The Keys study showed that adult man responds to semistarvation over a period of several months until he re-enters a steady state on only half the usual intake: energy supply before and at the end of the 24 weeks' semistarvation was 14.5 MJ (3468 kcal) and 6.6 MJ (1570 kcal). In the last four weeks of semistarvation, weight was stable to within 0.5 kg. No other study has demonstrated adaptation so effectively. GRANDE (1958; 1964) has emphasized that adaptation is normally considered to include those adjustments in behaviour and in biochemical mechanisms which do not impair the body's function.

Table 4. The body composition and total energy exchange of semistarved and "undernourished" men

Data for New Guinea Kaul men taken from NORGAN et al. (1974), where lying values are taken as equivalent to basal metabolic rate. Specific dynamic action calculated assuming equal to 10% energy intake and cost of physical activity calculated by difference as suggested by TAYLOR and KEYS (1945). Energy turnover presumed to be that of energy expenditure and not the lower value for intake measured by Norgan et al., but taken in Minnesota experiments to be equal to intake since this is precisely controlled and weight steady under both conditions of measurement. Most of the Minnesota data is taken from Table 181 with values for body fat taken from Table 457.