1. A device for monitoring food consumption comprising: a wearable sensor that is configured to be worn on a person's body or clothing, wherein this wearable sensor automatically collects data that is used to detect probable eating events without requiring action by the person in association with a probable eating event apart from the act of eating, and wherein a probable eating event is a period of time during which the person is probably eating; a voluntary human-to-computer interface, wherein this interface receives data from the person concerning the food that the person eats, wherein receipt of this data requires voluntary action by the person apart from the act of eating, and wherein the person is prompted to enter data using this interface when data collected by the wearable sensor indicates a probable eating event; and a data analysis component, wherein this component analyzes data received from the human-to-computer interface to estimate the types and amounts of foods, ingredients, nutrients, and/or calories that are consumed by the person.