Gwyneth Paltrow is being slammed over Goop's controversial weight loss advice

Gwyneth Paltrow's lifestyle website, Goop, has caused a stir after the actress' personal trainer, Tracy Anderson, answered the common question: How do we jump-start weight loss?

The fitness guru recommended working out daily, going "very low carb," and cutting out gluten entirely.

"You are how you move, you are how you eat," she explained.

"If you have weight to lose, you can effectively do a fourteen-pound weight loss in four weeks," she said. "This requires focus and physical, mental, and emotional willpower."

However, nutritional experts have hit out at Goop claiming the advice could be "extremely damaging."

Nutritionist Rhiannon Lambert, said she was "in complete shock that this article has been published, as this has the potential to harm a lot of relationships with food."

She also warns that exercising daily - as Anderson suggested - may not give your body time to recover.

"It is not sensible to eliminate whole food groups or make drastic dietary changes which are not sustainable — you may end up deficient in micronutrients and lacking important dietary diversity which aid gut bacteria," Lambert said.

Other health professionals felt Anderson's advice "promote[s] anorexia lite."