A back support system that comprises a belt portion being configured to provide back and abdominal support encircling a wearers waist, a compression pants portion and a hot or cold pack providing therapy to a wearers lumbosacral region. The belt portion has a left and right portions and a rear portion that extends upwardly from a cutout of the rear portion of the compression pants and is attached fixedly thereto. The rear portion of the belt portion has a pack support structure for receiving a hot or cold pack so as to maintain hot or cold therapy on the wearers back. Slots in the belt portion may accommodate vertically extending inserts of rigid plastic or spiral metallic to reinforce the belt portion over the lumbosacral region of the wearer. A front core support structure provides abdominal support in combination with the back support that supports the entire core of the wearers body. The garment can be changed to an immobilizing brace device by inserting optional rigid inserts.