HAVING gastric bypass sur­gery isn’t the only reason Roseanne Barr dropped a gut-busting 200 pounds. The ENQUIRER was a big help too.

The truth is that after her 1998 operation, her weight continued to yo-yo until we published shocking photos of the funnylady on vacation three years ago. They not only startled Roseanne but they motivated her, said the source.

The pictures, taken February 2011, showed the comic’s tummy bulging and excess skin hanging from her arm as she walked out of the ocean off Maui, Hawaii, in a one-piece swimsuit.

At the time Roseanne told The ENQUIRER, joking: “I weigh 175!!!!! I’m hot as hell!! Young male stars are all over me!”

But, in fact, those pictures were a wake-up call, revealed the source. “Roseanne vowed to get slim and fit once and for all after she saw those photos.

“Now she’s an exercise fanatic – and a total vegetarian. She eats less, she eats healthier and she works out like a mad woman, hours every day.

“She even has a gadget on her wrist called UP, a hard rubber bracelet that tracks your movements including measuring the number of steps she takes each day. She’s always trying to beat her goal. They recommend 10,000 footsteps a day. Some days she does 5,000. But others she does 15,000.”

The entertainer, who runs a maca­damia nut farm in Hawaii, always stays active and does her own chores to help keep in shape, said the source. “She plucks weeds and even tends to goats and chickens.”

The 61-year-old comedian oversees the business with her boyfriend John­ny Argent and her son Jake – and all the hard work has helped maintain her new svelte figure.

“The 5-foot-4 comic – whose weight reportedly once soared to well over 300 pounds – is now under 160 pounds,” said the source. “It’s her lowest weight in decades!”

Roseanne’s dramatic weight loss was the talk of an April 8 press event in Pasadena, Calif. She helped promote NBC’s new version of “Last Comic Standing,” which returns May 22 and features her as a judge.

Roseanne’s face was chiseled “and even her collarbone was visible beneath the layers of long necklaces as she posed for pictures,” said the source.

Jaws dropped as she proudly paraded her trim figure in a flat­tering outfit. “Her heavy days are behind her,” said the source. “And she wants to come down even more.”