EXCLUSIVE: Jason Biggs' Marriage 'Killed by His Extreme Diet' — 'He Became a Totally Different Person'

Jason Biggs' dramatic weight loss and growing Hollywood ambitions are said to have driven a painful wedge into his marriage to Jenny Mollen before the couple confirmed the end of their 18-year relationship, with insiders telling RadarOnline.com the actor "became a totally different person" as pressures mounted behind the scenes.

Biggs, 48, and Mollen, 46, announced their separation last week after months of speculation surrounding the state of their marriage.

The couple, who married in 2008 and share two sons – Sid, 12, and Lazlo, eight – had long cultivated a public image built on brutally honest discussions about parenting, addiction, therapy, and married life through podcasts, social media, television appearances and joint interviews.

But according to sources, tensions escalated after Biggs underwent a dramatic health transformation while simultaneously navigating the stress of directing his first feature film.

One insider close to the couple claimed the actor's physical transformation altered the dynamic inside the relationship.

They said: "Jason's entire mindset seemed to evolve after the weight loss. Before, he was far more relaxed and comfortable fading into family life, but once the transformation happened he became increasingly driven by image, career goals, and how he was perceived publicly. Friends started noticing that he carried himself differently and seemed much more consumed with maintaining this new version of himself.

"Losing the amount of weight he did before the break-up gave him a huge surge in confidence and energy, but it also shifted the balance of the relationship in ways neither of them really anticipated. People around them felt like Jenny was suddenly dealing with a different person emotionally and professionally.

"The transformation changed more than just his appearance – it affected his priorities, his outlook, and ultimately the dynamic between them. The diet was also extreme and affected his moods."

Biggs recently spoke publicly about the weight loss, explaining he initially changed his lifestyle after health concerns related to high cholesterol.

He said his "cholesterol came down 70 points" after adopting a stricter diet and fitness regime.

The actor is thought to have lost more than 40 pounds, though insiders suggested the physical transformation came with emotional consequences inside the marriage.

One source said: "At first, Jason was simply trying to get healthier and deal with the cholesterol issues, so nobody expected the transformation to become quite so dramatic. But as the weight kept coming off and people began complimenting him, it clearly had a major impact on his self-esteem. He became very proud of what he'd achieved physically and started carrying himself with a completely different level of confidence and swagger."

The source added: "It wasn't just about looking slimmer. The attention and positive reaction he received seemed to change how he viewed himself overall. Friends noticed he appeared more self-assured, more ambitious, and far more conscious of his image than he had been before."

Biggs remains best known for portraying Jim Levenstein in the hugely successful American Pie franchise alongside Seann William Scott, Alyson Hannigan and Eugene Levy.

In recent years, however, he has attempted to move beyond the comedy persona that defined his early fame.

Last year, Biggs completed work on his directorial debut, Untitled Home Invasion Romance, while he and Mollen also appeared together in Amateur Night and the revived food-and-entertainment series Dinner and a Movie.

Sources claimed the pressure attached to Biggs' directing ambitions created further strain at home.

An insider said: "Directing that movie became an all-consuming experience for Jason and it took over almost every part of his life for a while. He was obsessing over every creative decision, every reaction, and every detail because he felt an enormous amount of pressure to prove he could succeed outside the role people have associated him with for decades. It wasn't just another project to him – he viewed it as a defining moment for his career."

The source added: "There's a real anxiety that comes with being forever linked to one hugely iconic character and trying to evolve beyond that in Hollywood. Jason desperately wanted this next chapter of his career to be taken seriously, and that created a huge amount of stress behind closed doors. People close to them felt the pressure he was carrying eventually started bleeding into the relationship and creating distance between them."