Biggest weight loss

Some Australians had failed New Year resolutions to lose weight but Australia's Diet Champions have become three of the biggest weight losers.

After having children, Rosemary Filippello became very depressed when her weight ballooned out to 104 kilograms.

In one year she dropped an impressive 45 kilograms after opting to try the calorie-controlled Lite 'n' Easy program because her meals were home delivered.

"I've gone from a size 24 to a size eight and I feel wonderful," she said.

"I feel wonderful, I feel really, really good, I feel confident I can wear whatever I want, and I've got more energy."

Similar to Ms Filippello, mother of three, Debbie Molloy was also disappointed by her weight gain.

Eighteen months ago, Ms Molloy tipped the scales at 113 kilograms and was so big that she had to wear men's large size ski gear on a holiday.

The day after the trip, she called weight loss program Jenny Craig.

She replaced coke, pies, pizza and fish and chips with lean meat, salads, fruit, vegetables and an exercise program.

"In total I've lost about 43 kilograms," she said

"I was about 100 kilos when i got married and now I'm 70 kilos and I feel fantastic."

Depressed after a motorbike accident, Michelle Durbin found comfort in food and before she knew it, she weighed 120 kilograms.

Ms Durbin was shocked into action when she discovered she had type-two diabetes, at the age of just 32. She joined Sure Slim.

She lost almost half her body weight, her diabetes was under control and she no longer needed medication.

"If I can do it, anybody can do it," Ms Durbin said.

"I don't feel tired, I don't feel lethargic, my feet don't hurt, my back doesn't hurt, I feel great."

Dietician Dr David Crawford said most commercial weight loss programs have never been properly evaluated so it was important to approach them with caution.

"I'm not suggesting that commercial weight loss programs are not a useful way to go and I would encourage people who have weight problems to consider all the options," he said.

"Commercial weight loss program would be one of the options."

Dr Crawford said the answer was less processed food, more fresh fruit and vegetables and exercise.