That program is called "developmental" for a reason. It is to develop something. If your calories are too low you will be wasting your time with the program. I hate it when people do one of my programs that are based on GAINING and they want toi use a nutritional strategy designed to be LOSING. The results always end up being suboptimal and my program is wasted.
Loaded carries are very demanding, you can't simply add them to an already demanding training program. The body has a limited capacity to adapt. When |I design programs that include loaded carries I plan the rest of the program accordingly but using one less strength movement.