1. A device for monitoring food consumption comprising: a near-infrared spectroscopic sensor that is configured to be worn on a person's ear, wherein the near-infrared spectroscopic sensor automatically collects data concerning light energy in the near-infrared portion of the light spectrum that is reflected from the person's body and/or absorbed by the person's body; a microphone that is configured to be worn on the person's ear, wherein the microphone receives voice data from the person concerning the food that the person eats a voice-producing interface that is configured to be worn on the person's ear, wherein the interface produces a voice which prompts the person to enter voice data concerning what the person is eating using the microphone when data collected by the near-infrared spectroscopic sensor indicates a probable eating event; and a data analysis component, wherein this component analyzes data received from the near-infrared spectroscopic sensor and the microphone to estimate the types and amounts of foods, ingredients, nutrients, and/or calories that are consumed by the person.