Impact of Diet on PD Meds: Do you avoid protein in the day?

My husband takes Sinemet. We've been told to limit protein to his evening meal - avoid protein during the day. Due to his daily nausea, he mostly eats the BRAT diet (banana, rice, applesauce, toast.). We've eliminated nearly all sugar (no desserts), all processed foods, all red meat, milk products. He has lost 35 pounds and I feel his lack of energy is partially due to his lack of protein. Do others follow such a strict diet?