How can i fix a hernia that is due to diastis?

Good question: Diastasis is not really a hernia, technically speaking. It is separation of your muscles, but without herniation of viscera. To repair a diastasis, you need to bring the two edges together using sutures or bridge with prosthetic material. It is usually repaired for cosmetic purposes, not medical necessity.

Surgery: The only way to fix a hernia is a surgical procedure. If its part of a diastasis (widening of the connective tissue holding the "six pack" muscles together), such as a belly button hernia, mesh should generally be used. If it is only the diastasis, it can still be repaired, but will be considered cosmetic in most, but not all, cases. See your primary, general or plastic surgeon to find out more.