Taking an intermittent approach to the keto diet could offset some health consequences.
In a long-term relationship with the keto diet? You may want to consider a brief break-up, according to the results of a May 2024 study published in Scientific Advances.
The Context
The ketogenic diet involves limiting carbs (often to fewer than 50 grams per day), moderately restricting protein intake (often to 1 gram per pound of body weight), and allowing for unrestrained fat intake. Once glycogen stores are depleted, the liver converts more fatty acids into ketones, which are used by the body as the primary energy source.
This metabolic change has been linked with potential health benefits — including protective effects against neurodegenerative diseases and increased longevity in mice — and risks, such as elevated inflammation. Given the restriction required, dieters often struggle to sustain the eating pattern, particularly the low-carb requirement, in long-term studies.
The Details
The researchers of the Scientific Advances study set out to investigate how different approaches to the keto diet influenced its impact on cellular senescence (think: aging) — and what that might mean for health.
Male mice were randomly assigned to a control diet (17 percent calories from fat, 25 percent from protein, and 58 percent from carbohydrate) or a keto diet (90.5 percent calories from fat, 9.2 percent from protein, and 0.3 percent from carbohydrate) for four, seven, or 21 days. Mice were fed one of two keto diets: one that had higher levels of saturated fatty acids, or one that had higher levels of unsaturated fatty acids.
The researchers also studied the effects of an intermittent keto diet. Mice followed a keto diet for 31 days, ate a standard diet, or alternated between a four-day keto diet and a seven-day standard diet for three cycles.
The Key Findings
The mice that followed any continuous keto diet experienced an increase in cellular senescence in multiple organs, including the heart and kidney. When cells become senescent, they stop multiplying but don’t “die off” when they should. Instead, they linger, continuing to release inflammatory chemicals that can damage nearby cells, according to the National Institutes of Health.
That wasn’t the case for the mice that followed an intermittent keto diet. In fact, cellular senescence was prevented altogether when the rodents alternated between a keto diet and a standard diet. Even mice that followed a keto diet for seven days experienced a significant reduction in markers associated with cellular senescence (among other stress responses) after returning to a normal diet for one week. And those levels continued to decrease toward levels found in the control mice after two to three weeks of normal eating.
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The Impact
This build-up of senescent cells in the heart, kidneys, and other key organs can contribute to systemic inflammation, age-related disease, and even aging itself, according to the study authors. In fact, cellular senescence has been linked with cancer, diabetes, osteoporosis, cardiovascular disease, stroke, Alzheimer’s disease, and other conditions.
What’s more, the researchers say it may be the mechanism tying a long-term keto diet with inflammation-induced health risks, such as cardiac fibrosis and dysregulated mitochondrial function, which have previously been observed.
By preventing cellular senescence and the inflammation that can result, the study authors say an intermittent keto diet may positively influence health while having fewer side effects than a continuous keto diet. This flexible approach may be more accessible and sustainable than a rigid, long-term keto diet, too.
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The Expert Insight
In a press release, lead author David Gius, M.D., Ph.D., stated: “To put this in perspective, 13 million Americans use a ketogenic diet, and we are saying that you need to take breaks from this diet or there could be long-term consequences.”
“As cellular senescence has been implicated in the pathology of organ disease, our results have important clinical implications for understanding the use of a ketogenic diet,” he added. “As with other nutrient interventions, you need to ‘take a keto break.’”
The Caveat
As an animal-based study, the results may not be directly applicable to humans. The authors note that more research is needed to figure out whether intermittent keto dieting could actually be beneficial for people — and the best approach to it.
But health is multifactorial. While the keto diet might help promote certain health outcomes in one person, they may not materialize in another. As with any health intervention, a personalized approach is key.