Singers Mariah Carey and Beyonce Knowles apparently love it but the lemon detox diet has struck a particularly sour note for nutritionists.
Aussie experts have voted the two-week water, lemon juice, cayenne pepper and maple syrup fad as the worst diet for the third year in a row.
Read more: Don't add these diets to your to-do list
There's no one-size-fits-all solution to losing weight, says association spokesperson Melanie McGrice, a practising dietician.
"The problem with fad diets is they're all about restrictive eating patterns that you can't stick to over the long haul," she said. "They may even undermine your health.
"What you lose on detox diets, like the lemon detox diet and SkinnyMe tea, is usually fluid, healthy gut bacteria and electrolytes."
She says people don't need to go on severe detox diets because the lungs, liver, and kidneys provide the function "every minute of the day".
People who want to detox should cut down on fatty, highly processed foods and alcohol and caffeine.
A big danger is diets that cut out entire food groups.
"Diets such as the Ashy Bines Bikini Body Challenge demonise certain foods and make it a challenge to meet nutritional needs," Ms McGrice said.
She suggests that people focus on fresh, seasonal produce and follow the quarter, quarter, half rule.
This means one quarter of a plate should be low-GI carbohydrates, another quarter should be lean protein and half the plate should be vegetables in a variety of colours.