From the future feline website:
Physiologically, the cat is adapted to gorge food, followed by periods of fasting. This eating habit is necessary to provide sufficient time between meals for the body to de-tox, because a nearly all meat diet produces many toxic metabolic by-products, which are naturally filtered from the blood by the kidneys, and excreted in the urine. If the cat were to eat continuously, high toxic levels would be maintained in the blood stream and accumulative effect the cat's health. Meal feeding in 8-12 hour intervals assures that toxins in the blood peak only for short periods after ingestion and during digestion, after which they are nearly completely filtered from the body.