Perhaps we now understand Toronto Mayor Rob Ford's aversion to gravy at city hall.

Ford -- who once described himself as "300 pounds of fun" -- is set to launch a weight loss campaign next week.

The mayor, along with brother and fellow council-member Doug Ford, will hold public weigh-ins with an aim on losing weight and raising money for charity.

Doug Ford told CP24's Stephen LeDrew on Wednesday that he wants to get the entire city involved, and expects public pressure will keep them on target.

"What the mayor and myself decided to do is get healthy in 2012. We want to cut the fat from the City of Toronto in more ways than one. So we'd love everyone to join us and get involved," he said.

"We have set targets in the past that we've met and we're going to meet this target."

Doug Ford said he and Mayor Ford were working out details to hold a big weigh-in on Monday morning and had plans to hold public walkabouts in the city every weekend.

"Let's get healthy in 2012. We need a healthy budget and we all need to be healthy along with that," he said.

The Etobicoke councillor admitted he has a bit of a sweet tooth, adding that chocolate milk was a significant soft spot.

"I am addicted to chocolate milk. I drink it all the time. And I have to cut out that bowl of ice cream I have before I hit the sack," he said.

Obesity expert Dr. Yoni Freedhoff, the founder of Ottawa's Bariatric Medical Institute, says he supports the Ford brothers' public pledge to lose weight.

Freedhoff recently put out a call through his blog, "Weighty Matters", calling on health professionals to show their leadership in promoting healthy living by keeping their own public food and exercise diaries. In a matter of days he has signed up 70 doctors and nurses to the health challenge.

"We need to set examples for our patients, and healthy living is crucial, healthy living is preventing problems before they happen," said Dr. Freedhoff.

Having politicians inspire constituents with a healthy lifestyle can also have a huge payoff.

But Dr. Freedhoff says he's a little worried that the Ford brothers have given little indication of how they hope to drop the pounds, but he hopes they pick a sensible plan, rather than a lose-weight-quick scheme.

"My advice to everybody, including Mr. Ford, is that whatever they do to lose weight, that they like enough to keep doing," Freedhoff told CTV News. "Too often, people choose suffering as their modality of weight loss. And human behaviour as it is, we won't suffer forever."

The Fords wouldn't be the first politicians to lose weight while in office. During his time in the mayor's chair, former Toronto mayor David Miller lost 50 pounds through regular workouts and by cutting out junk food.

Former U.S. president Bill Clinton gained 20 pounds while in office. But after suffering a heart attack and undergoing a quadruple bypass after leaving the White House, he has gone on to lost 25 pounds and is now a vegan.

The campaign begins Monday with the brothers undergoing a public "weighing" at city hall. They will also be issuing a challenge to other city mayors to lose weight and try to maintain a healthy lifestyle, while in office.