A Georgia soldier who argued that a crash diet drove him to kill a superior has been sentenced by a military jury to life in prison without the possibility of parole.

Staff Sgt. Rashad Valmont was sentenced Friday, a day after he was convicted of premeditated murder in the June 2010 slaying of Master Sgt. Pedro Mercado at Fort Gillem outside Atlanta.

Valmont's attorneys say they'll appeal. They insist the 30-year-old Army Reserve soldier was delirious and dehydrated from crash dieting after a different supervisor told him to lose weight quickly.

Valmont walked into Mercado's office and shot him six times with a handgun. He then drove to a nearby police station and surrendered. The 47-year-old Mercado had served in Iraq and Afghanistan and was nearing retirement.

The trial was conducted at Fort Stewart in southeast Georgia.