I will be there in August, too bad we aren't there at the same time. I plan on 50 kalo as well.
For pizza I have also been hearing good things about Seu and will probably hit Stefano Callegari's Sbanco.
Gelato at Verde Pistacchio is legendary.
Restaurant Felice a Testaccio and nearby Salumeria Volpetti are favorites of Danny Myer.
Trecca Cucina Di Mercato is supposedly Bonci's favorite restaurant
Roscioli, L’Osteria di Monteverde, Colline Emiliane, Trattoria da Danilo, La Pergola are all on my list as well.
I will be gaining more than a few lbs I'm sure!