New methods and systems for noninvasive glucose monitoring and sensing with electromagnetic waves or ultrasound are disclosed. The methods are based on absolute or relative measurement of tissue dimensions (or changes in the dimensions) including, but not limited to: thickness, length, width, diameter, curvature, roughness as well as time of flight of ultrasound and optical pulses and optical thickness, which change with changing blood glucose concentrations. By measuring noninvasively absolute or relative changes in at least one dimension of at least one tissue or tissue layer or absolute or relative changes in time of flight of ultrasound or optical pulses, one can monitor blood glucose concentration noninvasively.