A diet made up of lemon drinks, and another that advises you to replace breakfast with black coffee, are among the top three diets to avoid in the new year, according to the nation's dietitians.
The Lemon Detox Diet, the Acid and Alkaline Diet and the Six Weeks to OMG Diet were voted the worst fad diets in an online survey completed by more than 230 members of the Dietitians Association of Australia.
Wollongong dietitian Kate Battocchio said many people turned to fad diets to offset the excesses of the silly season.
However, she said while people may lose weight on these diets, they usually put it all back on again - and more - as their metabolisms slowed as a result.
"The problem with any fad diet is that they generally target one of the core food groups and eradicate all foods from that food group," Battocchio said.
"But each of the food groups is designed to provide you with particular nutrients that are needed for a balanced diet."
For the second consecutive year the Lemon Detox Diet was deemed the worst out of nine popular diets, with three-quarters of dietitians voting against it.
Battocchio said the 10 to 14-day cleansing program involved drinking six to nine glasses each day of lemon detox drinks.
"This diet does not provide the body with the essential nutrients it needs, and it's impossible to maintain for any length of time," she said.
The Acid and Alkaline Diet also polled poorly in the survey, and Battocchio said the concept behind it was ill-advised.
"This diet promotes 'alkaline' foods, and recommends restricting 'acidic' foods which include bread as well as meat and dairy foods," Battocchio said.
"The kidneys and the liver and other receptors in the body naturally control acidity. If there's too much acidity, these control mechanisms kick in to restore the optimal balance anyway."
Meanwhile, the Six Weeks to OMG diet suggests skipping breakfast to instead start the day with a black coffee and some exercise, while carbohydrates are limited and protein promoted.
"It's been shown time and time again that groups of people who eat breakfast generally have a healthier weight than those who don't," Battocchio said.
So, she said, avoid the gimmicks or quick fixes to lose weight - instead stick to the slow-but-sure method of eating a wholesome, nutritious and balanced diet.