The alkaline diet touted by Hollywood celebrities for weight loss and to avoid diseases such as cancer and osteoporosis promotes eating more vegetables, but the premise behind it is junk science, some experts say.

Proponents of the alkaline diet claim that when eating foods that lead the body to produce acids, such as meat, dairy and refined sugars, the mineral stores in our bones can become depleted and lead to illness.

In general, the diet advocates eating more of most fruits and vegetables, nuts and legumes instead of meat or grains.

Vegetables

There's no science behind the alkaline diet, a dietitian and chemist say. (Czarek Sokolowski/Associated Press)

"If it's green, high water content you can pretty much say it's alkaline," said Julie Cove of Victoria, who runs a website  promoting the diet. "The key is add way more greens into your diet."

Hydration is another pillar of the diet some companies are profiting from. A $60 water pitcher, for example, claims to make water alkaline by adding minerals.

But our bodies don’t need help to do that. Moreover, the digestive system treats all foods the same way, said Joe Schwarcz, a chemist at McGill University

Since you cannot change the pH of your blood, "drinking alkaline water makes zero sense whatsoever," Schwarcz said.

In a Petri dish, cancer cells have been shown to multiply more in an acidic environment. But that can’t be extrapolated  to the body.

"What has happened in this case is a bit of scientific fact was taken completely out of context and woven into a fabric of nonsense," Schwarcz said.

Christy Brissette, a registered dietitian at the Princess Margaret Cancer Centre in Toronto, is concerned that the diet doesn’t work and could hurt some patients by putting them at risk of malnutrition.

"Some of the healthy foods that this diet limits are things like mushrooms, tropical fruits and berries," Brissette said. "I’d encourage people to pick the foods that they eat based on the nutrition in them, rather than looking at every single item and questioning is it acid, is it alkaline?"

With files from CBC's Kim Brunhuber