'Feast and famine' diet may help you live longer

 Intermittent fasting may help people live longer and healthier, according to a new study.

PTI| Last Updated: Mar 01, 2015, 18:58 PM IST

Washington: Intermittent fasting may help people live longer and healthier, according to a new study.

Researchers at the University of Florida have found that putting people on a feast-and-famine diet may mimic some of the benefits of fasting, and that adding antioxidant supplements may counteract those benefits.

Fasting has been shown in mice to extend lifespan and to improve age-related diseases. But fasting every day, which could entail skipping meals or simply reducing overall caloric intake, can be hard to maintain.

Researchers measured the participants' changes in weight, blood pressure, heart rate, glucose levels, cholesterol, markers of inflammation and genes involved in protective cell responses over 10 weeks.

"We found that intermittent fasting caused a slight increase to SIRT 3, a well-known gene that promotes longevity and is involved in protective cell responses," Michael Guo, a UF MD-PhD student who is pursuing the PhD portion of the programme in genetics at Harvard Medical School.

The SIRT3 gene encodes a protein also called SIRT3. The protein SIRT3 belongs to a class of proteins called sirtuins. Sirtuins, if increased in mice, can extend their lifespans, Guo said.

Researchers think proteins such as SIRT3 are activated by oxidative stress, which is triggered when there are more free radicals produced in the body than the body can neutralise with antioxidants.

However, small levels of free radicals can be beneficial: When the body undergoes stress - which happens during fasting - small levels of oxidative stress can trigger protective pathways, Guo said.

"The hypothesis is that if the body is intermittently exposed to low levels of oxidative stress, it can build a better response to it," said Martin Wegman, an MD-PhD student at the UF College of Medicine and co-author of the paper published in the journal Rejuvenation Research.

The researchers found that the intermittent fasting decreased insulin levels in the participants, which means the diet could have an anti-diabetic effect as well.

The group recruited 24 study participants in the double-blinded, randomised clinical trial. During a three-week period, the participants alternated one day of eating 25 per cent of their daily caloric intake with one day of eating 175 per cent of their daily caloric intake.

For the average man's diet, a male participant would have eaten 650 calories on the fasting days and 4,550 calories on the feasting days. To test antioxidant supplements, the participants repeated the diet but also included vitamin C and vitamin E.

At the end of the three weeks, the researchers tested the same health parameters. They found that the beneficial sirtuin proteins such as SIRT 3 and another, SIRT1, tended to increase as a result of the diet.

However, when antioxidants were supplemented on top of the diet, some of these increases disappeared.