Both studies tested the effects of four diet types - ketogenic, low carbohydrate, high fat, or control - in mice. The scientists used tasks involving mazes, balance beams, and running wheels to test the development of the mice's cognitive skills and physical strength as they aged.
The researchers also monitored the mice for alterations in heart function, and any changes in the regulation of gene expression.
What the researchers at the Buck Institute - in collaboration with teams from other institutions - found was that the effects of the ketogenic diet on the body were very similar to those of fasting and other such dietary restrictions. For example, it impacted insulin signaling and gene expression in much the same way that fasting would.
The Buck Institute team found that a keto diet fed to mice on a cyclical basis - that is, alternated with the control diet - prevented obesity, reduced mid-life mortality, and prevented memory loss.
"The older mice on the ketogenic diet had a better memory than the younger mice. That's really remarkable," says Dr. Verdin.
The keto diet can raise the concentration of beta-hydroxybutyrate acid (BHB) in the body, which, the researchers note, improves memory function.