Intermittent Fasting Is as Good or Better Than Continuous Calorie Restriction

According to Dr. Stephen Freedland, associate professor of urology and pathology at the Duke University Medical Center, "undernutrition without malnutrition" is the only experimental approach that consistently improves survival in animals with cancer, as well as extends lifespan overall by as much as 30 percent. 

Interestingly enough, intermittent fasting appears to provide nearly identical health benefits without being as difficult to implement and maintain. It's easier for most people to simply restrict their eating to a narrow window of time each day, opposed to dramatically decreasing their overall daily calorie intake.

Mark Mattson, senior investigator for the National Institute on Aging, which is part of the US National Institutes of Health (NIH), has researched the health benefits of intermittent fasting, as well as the benefits of calorie restriction. According to Mattson, there are several theories to explain why fasting works:

"The one that we've studied a lot, and designed experiments to test, is the hypothesis that during the fasting period, cells are under a mild stress, and they respond to the stress adaptively by enhancing their ability to cope with stress and, maybe, to resist disease... There is considerable similarity between how cells respond to the stress of exercise and how cells respond to intermittent fasting."

In one of his studies, overweight adults with moderate asthma lost eight percent of their body weight by cutting their calorie intake by 80 percent on alternate days for eight weeks. Markers of oxidative stress and inflammation also decreased, and asthma-related symptoms improved, along with several quality-of-life indicators.

More recently, Mattson and colleagues compared the effectiveness of intermittent fasting against continuous calorie restriction for weight loss, insulin sensitivity and other metabolic disease risk markers. The study, published in the International Journal of Obesity in 2011, found that intermittent fasting was as effective as continuous calorie restriction for improving all of these issues, and slightly better for reducing insulin resistance. According to the authors:

"Both groups experienced comparable reductions in leptin, free androgen index, high-sensitivity C-reactive protein, total and LDL cholesterol, triglycerides, blood pressure and increases in sex hormone binding globulin, IGF binding proteins 1 and 2. Reductions in fasting insulin and insulin resistance were modest in both groups, but greater with IER [intermittent fasting] than with CER [continuous energy restriction]."