Gwyneth Paltrow's personal trainer doesn't approve of celebrity-endorsed diets.

Tracy Anderson, who owns a chain of gyms with the Oscar-winning actress and is also responsible for sculpting the bodies of Nicole Richie, Jennifer Lopez, Kim Kardashian and Cameron Diaz, believes people shouldn't look to celebrities for workout and diet tips because they aren't experts.

The 38-year-old fitness guru told 'Access Hollywood Live' on Friday (10.01.14): ''Celebrity or non-celebrity, at this point in my career I don't know what clients are which, but what's bad now is that people, women at home look to celebrities and they're like, 'Oh this celebrity is doing this cleanse' or that celebrity is doing that. Celebrities are entertainers and they're not necessarily experts, so you need to make sure that you're doing what is right for you and you need to be following an expert.''

Tracy's comments came just eight days after Gwyneth, who has penned two healthy eating cookbooks, published a new winter detox plan on her lifestyle website GOOP.com.

The 'Iron Man 3' actress, 41, previously admitted a juice cleanse once left her ''hallucinating after 10 days.''

She said: ''I've done juice cleanses in the past, and in my twenties I did the Master Cleanse, which left me hallucinating after 10 days. Be aware: a juice detox can crash your metabolism and lead to future weight gain.''

Meanwhile, Tracy believes that ''exercise'' is a must for everyone.

She said: ''There is no way around it. We have to take care of our bodies. We're machines, we don't want to be neglected.''