Is fat loss a big issue with Ultherapy?

Thank you for your question and I appreciate your concern. When Ultherapy is administered by an experienced, board-certified dermatologist with expertise in using the device, there should not be any fat loss with the treatment. Ultherapy uses targeted ultrasound energy to constrict underlying tissue and boost collagen levels, tightening skin from the inside out.
Use of ultrasound imaging during the treatment aids in the precision of placing the energy exactly where it will produce the best outcome. Typically, patients need just one treatment session to achieve long-lasting results. As long as you work with a qualified provider, you should see very good improvement. 

yearly thermage and ultherapy should be used to prvent sagging and slow down tthe aging process, fat loss shouldnt be seen if used properly.  my patients like morpheus more regularly for tightening, every 2-3 months.  at home dermarolling helps tighten skin and should be used weekly at home (see link to emeragecosmetics.com where we do free skincare cosnults daily)As we age the skin sags there is  nothing  you can do that but try preventative  energy-based or thread-based  treatments or get a neck/facelift earlier in the aging process.  There are numerous options and some can be used in combination to get best outcomes but you need a consultation with an expert.
Options include for skin tightening :
thermage radiofrequency to heat skin and tighten it over time and prevent the aging processultherapy highintensity ultrasound to contract muscle and tighten the face and neck and prevent the aging processPDO nova threads or instalift threads for immediate lifting without surgery and long term collagen productionsculptra injections for collagen production to areas of the face and neck with crepe skin or early saggingbtl exilis ultra, venus legacy, thermi250 , or inmode forma/contoura  for constant collagen stimulation monthly with facialsfacelift/necklift with fat grafting/fillers if you need a big improvementThermiRF or J plasma /Renuvion or Inmode FaceTite   internal heating and tightening to long term internal heating and tighting with or without surgeryPlatysmaplasty to tighten the muscles of the neck long term and create contourFacial implants or fillers to contour the jawline and chin to improve the apperance of the nec kFractora/Morphenus8 or Intensif microneedling RF for improve superficial tightening, neck and chest wrinkling and crepe skin 
You need to see an expert in facial sculpting and age prevention.  Best, Dr. Emer.

I'm not sure how many people suffer fat loss from Ultherapy. But I regularly see people in my office for fat grafting after Ultherapy, radiofrequency or IPL have left them with fat loss and unevenness. I'm sure some people see nice results.  I don't offer these services in my medical spa because of what I have seen.