New wearable and non-wearable systems for noninvasive glucose sensing include an ultrasound generator, an ultrasound detector and a feedback unit. Methods for noninvasive glucose sensing using a wearable or nonwearable device include measuring a thickness (geometrical and/or optical) of a target tissue or a time of flight of ultrasound or optical pulses in the target tissue and determining a glucose value from the thickness of the target tissue or the time of flight in the target tissue in accordance with a target tissue thickness (geometrical and/or optical) or time of flight versus glucose calibration curve using new methodology for computing glucose concentrations with or without invasive measurements and simultaneously monitoring and generating a fitness index (FI), a body weight index (BWI), and/or a hydration index (HI).
