Fasting as little as eight days a year could have significant anti-aging benefits, even for older people and cancer patients.
Research conducted at the USC Davis School of Gerontology indicates that fasting for two to four days at a time can regenerate your entire immune system — especially for cancer patients undergoing chemotherapy.
“When you starve, the system tries to save energy, and one of the things it does is recycle a lot of the immune cells that are not needed, especially those that may be damaged,” said study author Dr. Valter Longo, a professor of gerontology.
Rebuilds Entire Immune System Even During Chemo
Dr. Longo said calorie restriction through fasting can be especially beneficial for older people (whose immune systems become damaged with age) and for cancer patients undergoing chemotherapy.
"If you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system," he said.
Scientists said fasting "flips a switch," and causes the body to break down white blood cells (which defend the body against disease) and create new ones.
"It gives the 'OK' for stem cells to begin proliferating and rebuild the entire immune system. And the good news is that the body got rid of the parts that might be damaged or old, the inefficient parts, during fasting."
Fasting for an entire day or two at a time can be extremely difficult for most people, but studies show you can reap the anti-aging (and weight loss) benefits of calorie restriction through intermittent fasting, which calls for alternating days of feeding and fasting.
Intermittent Fasting Spurs Weight Loss, Preserves Lean Muscle
IF proponents say periodically skipping meals accelerates weight loss by reducing digestion-related blood sugar spikes. Research also shows intermittent fasting can protect brain health and slow down aging by limiting the oxidative and metabolic stresses that damage cells, the Wall Street Journal reported.
According to research by the National Institute on Aging (NIA), intermittent fasting is better than conventional dieting for fueling weight loss, improving cognitive functioning, and maintaining lean muscle mass. "Just as exercise makes muscles stronger, fasting makes the brain stronger," said Dr. Mark Mattson, chief of the NIA's neurosciences lab.
Mattson said the chemicals produced by fasting also appear to boost people's moods. Mattson and his team conducted studies on animals with Alzheimer-like conditions, and found that alternating between days of fasting (typically this means calorie restriction, not eating nothing) and normal eating seemed to slow or even reverse brain impairment.
What's more, this pattern of intermittent fasting helped the animals maintain their lean muscle mass even as they aged — the exact opposite of what happens to both animals and people as they get older.
Similar experiments conducted on humans (alternating between days of normal eating and calorie restriction) showed the same effects. Dr. Mattson said fasting for short periods of time like 16 to 24 hours induces a state of stress in the body, which responds by releasing neurotrophic proteins that stimulate neurons and other cells.
Actor Hugh Jackman recently credited intermittent fasting for helping him achieve his rippling Wolverine body. Jackman, 45, said IF also gave him more energy and improved his sleep. Jackman said he was inspired to follow intermittent fasting after reading The 8-Hour Diet by David Zinczenko, the former editor-in-chief of Men's Health.
Hugh's 16/8 intermittent fasting protocol involves doing all his eating for the day during an eight-hour window and then not eating at all (except for water) for 16 hours. Jackman typically consumes all his calories between 10 am and 6 pm. It's an eating plan he follows even when he's not training for a role.
Intermittent Fasting Causes Surge in Human Growth Hormone
Research indicates that periodic fasting also dramatically increases human growth hormone. Reps from the Intermountain Medical Center Heart Institute said men who fasted for 24 hours experienced a 2,000% spike in HGH, while women saw a 1,300% increase. Studies show fasting stabilizes blood sugar and improves cholesterol.
Intermittent fasting has soared in popularity, thanks to the blockbuster success of The Fast Diet (or 5:2 diet), which calls for fasting (500 calories a day) for two days of the week and eating whatever you want the other five days.
Another popular intermittent fasting diet is the "Every Other Day Diet," where you alternate every other day between fasting and regular eating. Thousands of people claim they rapidly shed dramatic amounts of weight on both these IF regimes.
While most people may think dieters will overeat on their "feasting" days, this rarely happens, said Dr. Krista Varady, author of the Every Other Day Diet. "Something keeps people from really binging on that feed day,” said Varady.
“Something changes in the body on the fasting days. We're seeing that the people in the every-other-day group are losing more weight — about 5 to 7 pounds more — because they're just able to stick to it longer. They like that they're always able to look forward to the next day when they can eat whatever they want."