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ever heat dissipation threats are encountered in hot climates. On balance, stress should further suppress appetite. Previous research concurs with this expectation, in that normal eaters in both laboratory and field settings have responded to stress by decreasing their food intake (Herman and Vaccarino, 1992). The major exception to this rule is provided by dieters, who often overeat in response to distress; presumably most military personnel would not fall into this category. Military personnel, however, are quite likely to experience stress independent of heat, and the suppressive effect on appetite must be taken into account. Such stress may have debilitating effects on its own, to which may be added whatever stress stems from long-term hunger, such as may occur if stress suppresses appetite without a corresponding suppression of BW set-point.

Activity

One effective short-term technique for achieving thermoregulation is activity, because strenuous activity has a thermogenic effect (Bellward and Dauncey, 1988). Animals who are energy-deficient (either cold or hungry) become more likely to move around; such activity both provides endogenous heat directly and makes it more likely that exogenous energy sources may be encountered. Eventually, this strategy may backfire, if the extra expenditure of energy is not repleted; but in the short-term, the animal will be closer to a thermal optimum. Lassitude in the heat, conversely, probably serves a useful physiological purpose and should not be countermanded as assiduously as it might be in a temperate climate.

Food Temperature

If food contains energy, and its thermic effect depends on the amount of that energy pius the assimilative cost of consuming and digesting it, then it should follow that adding energy to the food by heating it ought to have a relatively straightforward additive effect on the food's thermic value. Conversely, cold food ought to minimize the thermic effect of eating. Indeed, one gets the impression that if the food is served at a temperature significantly below body temperature it will have a cooling effect; this cooling effect should be more reinforcing for people who are hyperthermic.

Eating tends to add energy in the form of heat to the body; if the heat-exposed individual must eat, he or she should presumably prefer a cool version of a food to a hot version, on thermic grounds. But the hot version may in general be perceived as more palatable, insofar as warming brings out the presumably pleasant flavor of the food (Trant and Pangborn, 1983). Cabanac (1971) might argue that the enhanced palatability of warmed food



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