Jared Fogle has been jackin' up the pounds since being sent to prison three months ago on child porn charges.

FOX's Tom Rigatti reports:

The former Subway pitchman, who claimed he lost 200 pounds by eating only Subway sandwiches, is quickly becoming "fat Fogle" again.

A prison insider tells In Touch magazine, Fogle has gained 30 pounds so far, mainly due to stress and depression.

His new prison diet includes Frosted Flakes, with fruit, or oatmeal with cake, for breakfast.

The insider says Fogle especially loves the twice-weekly "cake day" in the dining hall and buys Honey Buns by the box from the commissary on his weekly shopping day.

Fogle is serving a 16-year prison sentence in Colorado.

Tom Rigatti, FOX News.