Rather than cause volume depletion in the cheeks, Ultherapy fills in to some extent the depression in the mid and lower cheek that develops from descent of the face. We know that a contributing factor to the aged appearance is fat loss in the deep face, right on top of the bone. The lack of support that had been present when fat was there, causes the cheek to fall and fold over the smile crease making a bigger fold and creating jowl.
Ultherapy, by focusing ultrasound energy to the deeper planes of the face, tightens the connective tissue and creates new collagen. It is not known to reduce the fat. Once it lifts the lower face, there is less jowls and the skin and fat layers (not the deep fat) is raised up replacing some of the volume that is missing in the cheek.
The information provided in Dr. Shelton's answer is for educational purposes only and is not intended to constitute medical advice. The information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs.