Alternate day fasting, or intermittent fasting in general, is known to produce similar health and longevity benefits to the practice of calorie restriction. Intermittent fasting isn't as well researched as calorie restriction - by which I mean to say the evidence for health benefits is "only" very good rather than overwhelming, as in the case of calorie restriction. It's worth noting that there exist intriguing hints that the underlying biological mechanisms by which these benefits are conferred are different for these two strategies, despite the basic similarity: eating less while still obtaining all the necessary nutrients.
Over at the Longevity Meme I recently remarked upon a study showing improvement in heart function and overall health with age as a result of suppressing one gene involved in the calorie restriction response:
researchers compared aged mice with a functional p110alpha to aged mice with suppressed p110alpha and found that mice with the suppressed gene had: improved cardiac function; less fibrosis (fibrosis causes the heart to lose flexibility); fewer biological markers of aging; and a pattern of cardiac gene expression like that of younger mice.
By way of comparison, here is another study showing much the same result, but achieved through alternate day fasting rather than genetic engineering:
The free radical theory of aging is currently one of the most popular. In parallel, many studies have demonstrated the association of fibrosis and increased oxidative stress in the pathogenesis of some chronic human diseases, and fibrosis is often characteristic of aging tissues. One of the few interventions that effectively slows aging is calorie restriction and the protection against the age-associated increase of oxidative stress remains one of the foremost hypotheses to explain this action.
As an alternative to traditional calorie restriction, another dietary regimen, termed alternate-day fasting, has also been tested, whose anti-aging mechanisms have not been explored so much extensively. We thus studied the effects of alternate-day fasting, started at 2 months of age, on oxidative stress and fibrosis in the heart during aging. In the left ventricle of the heart of elderly (aged 24 months) versus young (aged 6 months) male rats we found a significant increase in oxidative stress paralleled by increased fibrosis. In parallel there was a significant increase in inflammatory cytokine levels and in NF-kB DNA binding activity with advancing age. Alternate-day fasting protected against all these age-related phenomena.
These data support the hypothesis that this kind of dietary restriction protects against age-related fibrosis, at least in part by reducing inflammation and oxidative damage, and this protection can thus be considered a factor in the prevention of age-related diseases with sclerotic evolution.
While researchers toil away with the goal of capturing some of the benefits of eating less in a drug, it's nice to know that you can be well ahead of the game if you so choose. Why not practice calorie restriction or intermittent fasting? It's not like there's a better game in town today for those of us who'd like to live long enough to see medical technologies capable of reversing aging rather than just slowing it down. You can alter your own metabolism through diet and exercise, and you can help to make the future of medicine arrive faster. If you're doing neither of those ... well, you'll only have yourself to blame for the years and health you miss out on.
Castello L, Froio T, Maina M, Cavallini G, Biasi F, Leonarduzzi G, Donati A, Bergamini E, Poli G, & Chiarpotto E (2009). Alternate-day fasting protects the rat heart against the age-induced inflammation and fibrosis by inhibiting oxidative damage and NF-kB activation. Free radical biology & medicine PMID: 19818847