31 years old male with face volume loss: Lipostructure? (Photo)

Thank you for your question.
When we lose weight, the skin on our face loses fat, which is the same
fat that suspends our cheeks higher. As
a result of your major weight loss, which resulted in
fat loss in your face you’re noticing hollowness.
I think you would be a great candidate for fat injections. Fat is taken from one area of your body,
usually the hips and injected into another area instead of synthetic fillers.
Fat transfers are a safe, non-allergenic way to recontour the face and add
definition to the cheeks and chin for very a natural and long lasting result.

Sculptra is a great filler if used properly by an experienced doctor with this product.  Over the past 9 years, I have used Sculptra for exactly the problems you point out.  I do not like hyaluronic acid like Restylane or Juvederm for improving volume to the cheeks.  Your tear trough is not the problem.  It is the volume loss to your cheeks.  Sculptra stimulates your body to make its own collagen.  You would need a series of injections to slowly build up the collagen, but building up the volume slowly is a better idea.  Fat grafting is another option, but a much different healing process.  I would advise you to see a board certified plastic surgeon who has experience with both Sculptra and fat grafting.  Good luck!