In addition, fasting is being explored as a supplemental treatment for brain injury, various cancers andStill, Valter Longo, a cell biologist and fasting researcher at the University of Southern California, says fasting is the body’s built-in fixer. It holds the power to heal. “But now, because we eat all the time, that inner repair has been eliminated,” he says. “We are not benefiting anymore from this ability.”, or CR. The methods have much in common.
That opportunity came by chance in 1991, when eight scientists entered Biosphere 2, an enclosed artificial ecological system near Tucson, Arizona. Their mission was to live for two years on food grown within the domed habitat to glean information for future biosphere space colonies. “They were malnourished, and they didn’t look healthy,” says Eric Ravussin, a metabolic researcher at the Pennington Biomedical Research Center in Baton Rouge, Louisiana.
Most people in the CR group completed the trial, but their average drop in calories was just 12 percent. It didn’t matter, though. Blood pressure, cholesterol, glucose, insulin and other biomarkers fell, possibly lowering their risk for heart disease, cancer and diabetes. On top of that, in mammals, production of a hormone that’s key to cellular growth, called IGF-1, drops, according to several papers. The hormone helps youngsters grow tall and strong, but in adults, it increases cancer risk and accelerates aging when not suppressed.
The big takeaway from Calerie, Longo says, is that the biomarkers of health are controllable through weight loss. “So if your doctor is telling you that you need drugs to control these things, that’s not true,” he says.Although CR might be metabolic magic, it’s no magic bullet. Some mice bred to carry certain genes for lab research don’t benefit from it, and it actually shortens life in other genetically modified mice.
Caloric restriction can lead to psychological issues, too. These were minimal in the Calerie trial, but Ravussin says that’s likely because people were screened for predispositions: food fantasies, irritability and social isolation, he says. Some of the Biosphere 2 scientists said they became prickly and obsessed about food during their 21-month deprivation.
By the 2000s, some fasting studies were showing better results than CR. In a 2003 experiment, Mark Mattson, a neuroscientist at Johns Hopkins University and the National Institute on Aging, found that mice fed on alternate days were healthier than mice that were calorie-restricted by 40 percent.