Some big names in the health and nutrition blogosphere came under heavy fire last month, as accusations of quackery — and one stunning admission of fraud — lit up pages usually dedicated to 48-hour cleanses and organic, cold-pressed juice. 

First there was Belle Gibson, the young Australian woman behind The Whole Pantry, who built a small media empire writing about health and nutrition after she supposedly beat terminal cancer with diet and lifestyle changes. 

Gibson admitted last month she never had cancer. "None of it's true," she told Australian Women's Weekly.

Meanwhile Dr. Mehmet Oz, host of the popular Dr. Oz Show, was denounced by a group of prominent doctors for "quack treatments," while blogger and bestselling author Vani (Food Babe) Hari was the subject of a scathing take-down on the website Gawker. 

'Anyone can call themselves a nutritionist.' — Dietitian Jennifer Sygo

Oz, who is vice-chairman and professor of surgery at Columbia University College of Physicians and Surgeons, has defended his endorsement of weight-loss products — saying his show provides "multiple points of view" including his own, and that his own views are offered "without conflict of interest." 

Hari has led campaigns against such perceived ills as the food dye formerly used in Kraft Dinner and an additive found in Subway sandwich bread. 

But she has drawn accusations of fear-mongering and quackery from the scientific community and, it seems, now has an arch-enemy in chemist and writer Yvette d'Entremont, a.k.a. the Science Babe. 

Hari is "the worst assault on science on the internet" d'Entremont wrote in the April 6 piece, which has drawn some 4.5 million views. 

In the resulting war of words, Hari accused d'Entremont of being a "pro-chemical" shill and suggested the article was part of a paid-for attack, claims d'Entremont has denied. 

High demand, no regulation

The situation is not a surprise, says dietitian and author Jennifer Sygo, since nutritionists have never been in higher demand in the media but remain an unregulated profession.

CORRECTION Weight Loss Advertising

Dr. Mehmet Oz testifies in Washington in 2014 over his endorsement of weight-loss products. (Lauren Victoria Burke/Associated Press)

"Nutrition is now a major player in the news cycle," says Sygo, who has been writing about health and food for the National Post since 2007. 

"I used to have to beg people to try to care about nutrition. Now it's a fiercely competitive environment where you want the person who has the latest thing — some superfood or some strategy for eating."

"That gets you a lot of press," she says, especially in 24-hour news and on social media, where being the loudest tends to get results. "But always remember, anyone can call themselves a nutritionist." 

Sygo says she suspects our overall conversation about food is moving away from the current obsession with "nutrient numbers" to a more informed consideration of how food is prepared, and under what conditions. 

Others are less optimistic. Criticism of popular personalities by scientists doesn't often reach the masses, says Dr. Yoni Freedhoff, an Ottawa-area doctor who treats people with obesity. 

"Celebrity and predatory hope have always been scourges on society, and I suspect, always will be," Freedhoff told CBC News.  

Joe Schwarcz, director of the Office for Science and Society at McGill University in Montreal, predicts the recent criticism will boost the careers of both Oz and Hari, even if their claims and arguments don't always hold scientific water. 

"In the quackery business, any publicity is good, it doesn't matter if it's criticism," says Schwarcz, who is among Hari's critics. 

"She'll be more popular than ever. So will Oz," he predicts. 

Schwarcz says the best protection against bad science, whatever its source, is better early education. 

Questions about health, nutrition and lifestyle "are issues people have to come to conclusions about by themselves, from within," he says. "Otherwise you're just listening to others and you don't know what kind of soapbox they're standing on — whether it's full of science or hot air."