Jennifer Garner Beating Ben Affleck Into Fighting Shape

Ben Affleck is getting his flabby dad bod whipped back into shape,  The National ENQUIRER has learned — by furious ex Jennifer Garner!

“Jen’s agreed to help him because their kids are so concerned about his health!” an insider tattled to The ENQUIRER. And it helps that the actress is in the best shape of her life, according to insiders.

“Jen is shredded!” our source spilled. “She worked out three hours a day for her new movie, ‘Peppermint,’ and is totally ripped!” Now she’s working Ben like he’s in boot camp! “She’s got Ben doing cardio, weight and resistance exercises — sweating off fat and building muscle,” the  source snitched.

“She’s even put him on a detox diet that includes smoothies made of veggies and fruit, along with a lot of lean protein like chicken and fish.” After the “Batman” stud wrecked their marriage with his boozing, gambling and cheating, the “Alias” beauty is getting a kick out of controlling his workouts and diet, said the insider.

“When Ben wants to stop after 100 push-ups, Jen tells him to do 50 more. Ben needs to get back into shape to play Batman again," the source added, referencing the actor's pre-mid-life crisis physique (shown). "So Jen’s doing him a favor. But she’s also enjoying watching him suffer.”