The Italian has warned the Black Cats squad they must be ready for pre-season training or they could face fitness problems in September which could hamper their campaign
The Italian's disciplinary actions at the Stadium of Light, which included fining players, were investigated by the Professional Footballers' Association in May.
Di Canio insists his squad must arrive from their holiday prepared for their pre-season campaign and claims it is normal for Premier League clubs to fine their players.
"Obviously the players have a programme to follow so that they are ready when pre-season begins," Di Canio told The Sun.
"When we start, we will start not that heavy, but there will still be a great deal to do and they have to be ready.
"It's normal in the Premier League, that players get punishment for breaking rules set down by the club.
"Everyone who comes back with more than two kilograms over what their weight should be, we're going to fine them.
"We test them before they go so everyone knows how they finished the season."
Di Canio believes it is vital for players to maintain their fitness throughout the summer and warns that poor conditioning prior to the season will have a negative impact at the start of the campaign.
"When they come back they're going to work three times a day, so it would be crazy to have put too much weight on in a short space of time," he added.
"How can it be possible to come back with seven kilograms extra?
"They have one month off and then one month to work at a high-intensity level and if they do not do that right, then in September, they'll still be heavy.
"You can't work if you've put seven kilograms on your shoulders.
"When I played, I came back with a player who was 10 or 11 kilograms over and he didn't play all season because he had injury problems."