Chemical Reactor Analysis and Optimal DigestionAn optimal digestion theory can be readily derived from basic principles of chemical reactor analysis and design

of energy and nutrient gain. According to the principles of dynamic programming, a method for formulating and solving optimization problems (Bellman 1957), the entire process is optimized only if digestion follows an optimal path constrained by the food items actually ingested. An animal feeding on a variety of foods should thus exhibit the flexibility to adjust digestion with respect to that range of food types. Conversely, the net rate of gain to an animal lacking such flexibility will be maximized over a restricted set of food types, making it a dietary specialist. To test these general predictions and to formulate more specific ones, we must identify the operating variables for each stage. Many foraging theories exist (e.g., Charnov 1976, Orians and Pearson 1979, Pyke 1984, Schoener 1971), but there are only rudiments of an optimal digestion theory (Milton 1981, Sibly 1981, Taghon 1981, Troyer 1984). Without such a theory, studies of digestive systems (e.g. gut anatomy, histology, or enzymology) tend to be static, piecemeal, and most often nonpredic-