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might be a conditional preference, based on the thermic effect of the food. Negative alliesthesia effects (that is, decreased acceptability) might be expected for warm food as the internal environment heats up. In other words, warm food may not be intrinsically more palatable; rather, its palatability may depend directly on the state of the organism (in this case, whether the organism is hypo-or hyperthermic). For Cabanac, it is not that the hot food is rejected by the heat-exposed individual despite its greater palatability but because heat exposure detracts from the food's palatability.

That heat exposure might shift one's preferences away from hot food and toward cool food is understandable. But another question arises: Should heat exposure increase one's attraction to cool foods rather than to no food at all? Cooling food produces a peculiar condition: the food still contains latent calories and is likely on those grounds to raise body temperature; but the cool physical state of the food is likely to have an immediately cooling effect in the mouth and perhaps even further down the alimentary canal. From a thermoregulatory point of view, is the hyperthermic individual better off consuming a cool food or none at all?

Type of Food

It is widely accepted that ''the amount of ... added heat, of course, varies with the type ... of food consumed'' (Rampone and Reynolds, 1991). Yet there appears to be only a small variation in the thermic effect of food depending on the type of food ingested. "Eating proteins, which are somewhat more complicated to break down inside the body than carbohydrates or fats are, tends to raise body temperature very slightly more than these other two basic food components do" (Beller, 1977). Beller goes on to note (pages 157 to 158) that "this difference has probably received more attention than it deserves in the popular literature about nutrition," an allusion to the allegedly weight-reducing properties of a high-protein diet. Balagura (1973), in discussing this issue, notes that in general, animals prefer carbohydrate diets and especially prefer fat diets over protein diets, so the fact that eating terminates sooner on protein diets may be more a function of the diets' limited palatability than of their greater thermic effect. Of course, in nonhumans, palatability is often difficult to disentangle from eating itself; but in humans, the expressed preference for fats and sweets is well known (Drewnowski et al., 1989), so that if less of a high protein diet is consumed, it may well be due to taste and texture factors rather than to thermal satiety feedback. Whether in making diet prescriptions we ought to consider the thermic effect of macronutrients—or confine ourselves to a consideration of basic nutritional balance—is difficult to assess at present.



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