SACRAMENTO — Out of trendy diets, it’s one of the most difficult to adhere to, and it also has produced some of the most dramatic results.
It’s called the ketogenic diet, and it’s recent popularity has been sparked in part by emerging research on its potential benefits.
Adding fuel to the fire, a new study of the diet’s effects on mice showed the high fat low carb regimen increasing both strength and longevity in the rodents. Conducted at the University of California Davis School of Veterinary Medicine, the study’s findings went beyond what researchers expected.
“The results surprised me a little,” says study senior author and nutritionist Jon Ramsey in a press release. “We expected some differences, but I was impressed by the magnitude we observed — a 13 percent increase in median life span for the mice on a high-fat versus high-carb diet. In humans, that would be seven to 10 years. But equally important, those mice retained quality of health in later life.”
Having recently surged in popularity due to the broad range of possible benefits and fitness celebrity adherents, the researchers say they still have much to learn about what happens in “ketosis.” Describing the state that occurs when low carbohydrate intake shifts the body from burning glucose as the main fuel source, to burning fat and producing ketones as the main source of energy, ketosis only occurs under specific conditions.
According to fitness author and former Ironman competitor Mark Sisson, it can take months for humans to adequately prepare to make the switch to ketosis.
“Ketogenic dieting is a big jump for some people,” Sisson says in The Definitive Guide to Keto. “You’re literally switching over to a new metabolic substrate. That can take some getting used to.”
Despite espousing the benefits of the ketogenic diet, Sisson also says he feels cautious about recommending it.
“A recent study of long-term (5 years) ketogenic dieting in patients with glucose transporter 1 deficiency syndrome found no apparent downsides. Bone mineral density, which can be a problem for growing kids on long term ketogenic diets for epilepsy, was unaffected,” he writes. “Yet, I’ll admit to being a bit leery of long-term, protracted ketosis in people who aren’t treating a medical condition. It just doesn’t seem necessary.”
The increased attention to the ketogenic diet comes as many researchers and public health officials look at the benefits of replacing carbohydrate calories with fat calories more generally. In most cases, the higher fat diets being studied aren’t stringent enough to result in ketosis.
One such large scale study presented at the recent European Society of Cardiology conference called for a reconsideration of global dietary fat recommendations in light of new evidence of increased mortality among those with high carb diets.
As far as the recent UC Davis study, the researchers said they were specifically concerned with the ketogenic diet and its effect on longevity.
“We designed the diet not to focus on weight loss, but to look at metabolism,” Ramsey said. “What does that do to aging?”
While the main question of the study was answered — yes, the ketogenic diet increases the median lifespan of mice — the researchers found it also increased memory and motor function as well as reducing inflammation and the incidence of tumors.
“In this case, many of the things we’re looking at aren’t much different from humans,” Ramsey says. “At a fundamental level, humans follow similar changes and experience a decrease in overall function of organs during aging. This study indicates that a ketogenic diet can have a major impact on life and health span without major weight loss or restriction of intake. It also opens a new avenue for possible dietary interventions that have an impact on aging.”
The study findings were published this week in the journal Cell Metabolism.