BALTIMORE, July 22 (UPI) -- Weight loss aside, cutting calories can be good for overall health, including staving off neurodegenerative diseases, according to recent research.
Researchers at Johns Hopkins University say cutting calories, if not including routine fasting as part of a normal lifestyle, may prevent progressive brain disorders such as Alzheimer's disease by promoting positive changes to the structure of the brain.
Dr. Mark Mattson, a professor of neuroscience at Johns Hopkins and chief of the neurosciences lab at the National Institute on Aging Intramural Research Program, says research has repeatedly shown fasting benefits the brain.
When people eat, glucose is stored in the liver as glycogen. When this has been used by the body, about 10 to 12 hours after consumption, the body starts burning fat for energy by converting it to ketones, which neurons use as energy.
Ketones have the ability to improve the performance of neurons on the brain, but Mattson says that if the glycogen in the liver has not been used up -- most people eat three meals a day and often snack between them -- the body never needs to start burning fat.
The brain produces a protein called brain-derived neurotrophic factor, especially when it is challenged during physical exertion, cognitive tasks or caloric restriction. BDNF is known to strengthen neural connections and increase the production of new neurons.
"Probably during evolution, BDNF evolved to play an important role in increasing neuroplasticity in the brain and forming new synapses crucial to learning and memory as well as mood and motivation," Mattson told the Johns Hopkins Health Review.
In his previous research, Mattson has found the improvement of neural connections in the hippocampus and protects neurons against the accumulation of amyloid plaques -- which play a key role in Alzheimer's disease.
"Fasting is a challenge to your brain, and we think that your brain reacts by activating adaptive stress responses that help it cope with disease," Mattson said. "From an evolutionary perspective, it makes sense your brain should be functioning well when you haven't been able to obtain food for a while."
Other studies have found similar results, including one conducted at the Massachusetts Institute of Technology in 2013, which found reduction of calories can protect against the neurodegeneration linked to a wide range of progressive, age-related brain disease.
A study in 2009 conducted in Germany found women who cut their caloric intake by 30 percent for three months saw their performance on memory tests improve by 20 percent, suggesting what Mattson says is correct.
"The results seem pretty dramatic," Mattson told CNN at the time. "Even though the number of subjects in the study was not really high, they had really high, statistically significant improvements in their performance on the memory test."
Currently, Mattson is conducting a study with obese people who are at higher risk for cognitive impairment to see if intermittent fasting -- using the 5:2, which includes limiting caloric intake to 500 calories per day on two nonconsecutive days each week -- can help reduce the risk for brain diseases.
Based on what he has already seen, and recent popularity of fasting diets, his hope is that more people will catch on and derive the cognitive benefits of caloric limitation.
"I hope it's not a fad," said Mattson. "There's a lot of science behind it, and the science is only increasing."