Accessory maker Jawbone on Wednesday unveiled "Up," a lifestyle gadget designed to encourage health and wellness. (Photo courtesy Jawbone)

For about a month, Hosain Rahman has worn the same wristband 24 hours a day, even while he sleeps, exercises and showers. The wristband isn’t his favorite watch; it’s the lifestyle gadget his company has been developing for years.

Accessory company Jawbone on Wednesday revealed Up, a hardware and software system that tracks your eating, sleeping and movements to give you a reading on your general health. The wristband, which is about the same size as a...