put on weight

Schon während der Abiprüfung hatte der Junge ohne Sport und mit viel Nervennahrung, etwas zugenommen. Da er den Rest des Sommers vor dem Fernseher faulenzt, ist seine Figur schon vor Studienbeginn ruiniert. 

Even during his school-leaving exams, the boy had gained some weight eating lots of food to nourishment for nerves and without doing any sport anymore. Since he spends the rest of the summer lazing around in front of the TV, his figure is already ruined before he even starts university.