Seven hundred and seventy-three adults who lost at least 8 % of their body weights were randomized to one of five ad libitum diets for 6 mo : 1 ) low-protein ( LP ) / low-GI ( LGI ) ; 2 ) LP/high-GI ( HGI ) ; 3 ) high-protein ( HP ) / LGI ; 4 ) HP/HGI ; and 5 ) control diet .