Josh Sosland, PortraitJosh Sosland, Editor of Milling & Baking News. 

KANSAS CITY For the last 10 years, the ketogenic diet has been the most visible version of low-carbohydrate dieting in the United States. A range of developments in recent months suggest the keto diet, and other fad diets, may be in decline.

A strong negative signal from a food company about the sustainability of the keto diet fad emerged in connection with the quarterly financial results of The Hain Celestial Group, Inc. A little more than a year after Hain Celestial acquired the Parmcrisps and Thinsters snack brands for $259 million, the company in its third quarter ended March 31 wrote off $156.6 million of its investment. The acquired brands experienced a significant drop in distribution, but Wendy P. Davidson, the company’s new president and chief executive officer, cited another reason for slashing the value of the acquisition.

“We believe in the better-for-you snacking category, absolutely, and this was a play in better-for-you snacking, certainly in high protein,” Ms. Davidson said. “So, all of the consumer trends from that standpoint were correct. Where we potentially got it wrong … is the reliance on keto as a diet relative to Parmcrisps and the subsequent decline in the keto category.”

A high-fat, low-carbohydrate regimen, the ketogenic diet gained popularity gradually and steadily during the 2010s about a decade after the Atkins Diet experienced a more abrupt bubble and bust. In The ketogenic diet has roots dating back much earlier than Atkins. The diet was developed about a century ago by Dr. Russell Wilder of the Mayo Clinic as a therapeutic treatment for pediatric epilepsy. Forcing the body to burn fat rather than carbohydrates, keto dieting leads the body to create elevated levels of ketone bodies, inducing a state known as “ketosis.” The treatment helped prevent seizures and was popular for decades until anticonvulsant drugs were introduced.

Not all signals have been negative for the keto diet. The International Food Information Council’s 2022 Food and Health Survey showed a slight uptick in the percentage of respondents saying they follow a keto diet, to 7% from 5% in in 2021. The latest figures, issued last week, showed a drop in 2022 to 4%. Google search data trends show interest in the keto diet in a steady and steep decline. From a peak in January 2019, searches of the term “keto” were down 66% in February 2022 and down 77% in May 2023.

The nutrition community continues to encourage the public to avoid keto and other diets that heavily limit intake of carbohydrates. In a statement published in the scientific journal Circulation in May, researchers from the American Heart Association said such diets “even when followed optimally, promote restriction of food groups that are considered essential features of a heart-healthy diet.” The AHA also characterized keto dieting as highly unpleasant. “Many individuals experience ‘keto flu’ with a constellation of symptoms, including headache, fatigue, difficulty sleeping, irritability, nausea, and constipation, at the beginning of the diet, which may be a deterrent for continuation,” the researchers said.

Just as pharmaceuticals undercut keto dieting as an epilepsy treatment, drugs appear to be doing the same for keto and other fad diets as weight-loss strategies. Diets fail to bring sustained weight loss for most dieters, but a new class of drugs appears to be effective at helping patients shed weight. Semaglutide, a medication for the treatment of Type 2 diabetes, has become wildly popular as an anti-obesity treatment. Supplies of the medication, sold under the brand name Ozempic, have become scarce. Its maker, Novo A/S, in 2021 introduced another version of the drug under the brand name Wegovy specifically targeting obesity. The medications work by suppressing appetite.

Carbohydrate avoidance certainly will not go away overnight. Additionally, increased uptake of appetite suppressing medications may have a negative macro effect across the food industry broadly in a country in which the population widely overconsumes. Still, grain-based foods should be grateful for just about anything that helps eliminate the industry’s longstanding nemesis — fad dieting.