"It's really a starvation diet where people aren't eating anything at all for one to two weeks."
McGrice said the Acid Alkaline Diet and the Six Weeks to OMG Diet peddled misinformation to sell their diet regimes to consumers.
Personal trainer Paul Khanna's Six Weeks to OMG diet (written under the name Venice A Fulton), which suggests skipping breakfast every morning before exercising, incorrectly claims broccoli is as bad as cola drinks, McGrice said.
Meanwhile, avoiding acidic foods under the Acid Alkaline diet is unnecessary because the body naturally regulates acidity.
"I hope in 2013 that Australians might actually start using some common sense to lose weight and give the fad diets a miss and instead choose a healthier lifestyle," McGrice said.
"If you want to try and lose weight that's fine but don't do so at the expense of your nutrition."
More than 230 DAA members voted in the worst diets survey with almost three-quarters nominating the Lemon Detox Diet as the most irresponsible culprit.
McGrice said a good way to start the new year for those hoping to lose weight was to have more home-cooked meals and start walking regularly.
"Extreme diet measures are unnecessary and counterproductive," she said.
Tips to ditch fad diets in 2013:
* Watch out for gimmicks or quick fixes. See an accredited dietitian if you need help
* A miracle diet won't solve your weight problems. The unsexier solution is a wholesome, nutritious, balanced diet
* Carbohydrates are essential for effective brain function. Low carbohydrate diets won't help you perform at your best
* Get half vegetables, one quarter carbohydrates and one quarter protein on your plate at breakfast, lunch and dinner
* No need to ban certain foods - you'll only crave them more. Plan small amounts of "treat" foods into your week
Source: Dietitians Association of Australia
- AAP