The macronutrients people on the keto diet focus on include:

• 55 to 60% of calories from fats
• 30 to 35% of calories from protein
• 5 to 10% of calories from carbohydrates (20 to 50 grams of carbs).

To compare this to the Food and Drug Administration (FDA) recommendations, the FDA recommends that fewer than 10% of people’s calories come from saturated fats, which are the type of fats found in beef, butter, and pork.

The FDA does note that people should focus on foods that are a source of unsaturated fats — such as fish, avocado, and walnuts — since they may help with cholesterol management.

Additionally, the FDA recommends that people consume 275 grams of carbs per day, which is significantly higher than the carb intake recommended for the keto diet.

This study involved testing the effects of consuming a diet high in fat in mice. One group of mice served as the control group and ate a diet with a caloric makeup of 17% from fat, 25% from protein, and 58% from carbohydrates.

The test group mostly ate Crisco, which contained 84% unsaturated fat and 14% saturated fat. In the Crisco group, 90.5% of calories came from fat (notably higher than the standard keto diet), 9.2% of calories came from protein, and 0.3% of calories came from carbohydrates.

The mice began eating their assigned diets between 35 and 42 days old, and they continued with their diets for either 7 or 21 days. At this point, the researchers euthanized the mice and evaluated them.

The researchers monitored various health markers in the mice, such as ketones, glucose, insulin sensitivity, triglycerides, low-density lipoproteins, and high-density lipoproteins. They also checked samples of the heart, liver, and kidneys for evidence of damage.

The scientists saw that in some of the major body organs, including the heart and kidneys, the ketogenic diet contributed to cellular aging.

The mice in the Crisco group had a buildup of senescent cells which are old cells that stop dividing but do not die off.

The researchers were curious how the mice from the Crisco group would compare to a group that consumed a different ketogenic diet and tested these mice with cocoa butter. Cocoa butter has more saturated fat than Crisco (40% unsaturated fat and 60% saturated fat).

The cocoa butter group also showed evidence of organ damage and cellular senescence.

Delving into the issue further, the researchers learned that the cellular senescence process was likely tied to the proteins AMPK and p53. When the researchers blocked the pathways of these proteins, the mice did not have the same levels of cellular senescence.

The scientists were also curious as to whether cellular senescence was reversible, so they tested more mice on a ketogenic diet, checked their biomarkers, and found that given time, the cellular aging markers decreased after quitting the diet.

While ketogenic diets may cause damage, the research shows that it is possible to manage this either through medications that block certain proteins, or through adhering to the diet intermittently.

Scott Keatley, a registered dietician and owner of a private nutrition practice in New York City, not involved in this research, spoke with Medical News Today about the study findings.

“The findings are significant as they provide a mechanistic understanding of how long-term ketogenic diets can potentially lead to cellular aging and dysfunction in critical organs such as the kidneys and heart,” he commented.

“This underscores the need for careful consideration of diet duration and composition when recommending ketogenic diets, particularly for patients with existing organ concerns or those at risk for chronic diseases,” continued Keatley.

He also noted that longitudinal trials in humans are the next step to confirming whether ketogenic diets cause cellular senescence.