Patterns of eating as a function of the cost of the meal.

Rats were required to complete fixed ratio schedules (FR 20-FR 2560) of wheel turns to obtain access to food. By decreasing meal frequency and increasing meal size directly as functions of the fixed ratio requirement, animals controlled total daily food intake and body weight relatively constant until the highest ratio requirement was introduced. These functional changes in feeding patterns provide experimental support for theoretical models of optimal feeding strategies. At the highest ratio requirement, as animals lost weight, they increased running and therefore opportunities to feed, however, food intake continued to decrease with increasing exposure to this schedule. As rats on this schedule initiated feeding each time food became available, but did not eat large enough to this schedule. As rats on this schedule initiated feeding each time food became available, but did not eat large enough meals to maintain body weight, it is suggested that activity may interest with satiety mechanisms to produce termination of meals.