During an appearance at Manor Nightclub in Chicago, the 37 year-old told People.com: 'I'm definitely still working out, but I do less intense workouts because I'm not getting as much sleep now.
'So the fitness [regime] is still intact, but lately I just haven't been able to go at it as hard as I used to.'
Lopez, whose daughter Gia was born on September 11, is extremely happy to be a dad, with or without his six pack.
He added: 'I love [being a father] more than anything. I absolutely cannot wait to get home to see her. She's so amazing, this whole experience is so amazing.'