Our Longevity Diet

So far, I have not found any clear description of who came up with the idea of intermittent fasting in the first place. Apparently, it was used with lab rats in dietary studies going back at least to the early 1980s, and probably earlier.

Studies as far back as the 1930s demonstrated the effects of caloric restriction:

McCay, C. M., and M. F. Crowell. 1934. Prolonging the life span. Science Monthly 39:405–414

I haven’t been able to find a copy of that study on-line, but it sparked subsequent research which confirmed that some animals fed 40% to 60% of their normal diets lived as much as twice as long as those that ate normally. Almost all animals lived longer on restricted diets, though the specifics vary from one species to another.

Who it was that jumped from those findings to demonstrate that intermittent fasting could be just as beneficial, I have yet to discover. The earliest reference I have noticed so far dates from 1983:

Goodrick C. L., Ingram D. K., Reynolds M. A., Freeman J. R., and Cider N. L. (1983) Differential effects of intermittent feeding and voluntary exercise on body weight and lifespan in adult rats. J. Gerontol. 38, 36–45.

This article is also elusive on-line, though it is available for purchase. The abstract, however, is widely available, and speaks of alternate day feeding as it were nothing novel:

Effects of intermittent feeding upon growth, activity, and lifespan in rats allowed voluntary exercise.
Goodrick CL, Ingram DK, Reynolds MA, Freeman JR, Cider NL.

From weaning until death, male Wistar rats were housed in activity-wheel cages with one group maintained on an ad libitum (AL) diet and another provided the diet every-other-day (EOD). EOD-fed rats had a mean lifespan of 124 weeks compared to 103 weeks for AL-fed rats. While post-weaning body weight and growth rates were reduced among the EOD-fed animals compared to AL-fed animals, there was no significant difference in growth duration. Positive correlations were observed between lifespan and estimates of growth rate and duration in the AL group but not in the EOD group; thus, little evidence was produced to support the hypothesis that growth rate is inversely related to longevity. While the EOD feeding regimen resulted in higher activity levels later in life, wheel activity levels were actually lower in this group in early life compared to the AL group. The observation of reduced wheel activity among young rats fed EOD was replicated in a second experiment. Thus, little support was obtained for the hypothesis that increased activity mediates the beneficial effects of dietary restriction on longevity, unless this mechanism is active late in the lifespan.

Interestingly, this study only showed a 20% increase in longevity — well below the results demonstrated by some of the subsequent research.

It was not until the 1990s that humans began getting interested in trying caloric restriction. The intermittent fasting alternative doesn’t seem to have occurred to the public at large until the early 2000s, even though it was known to researchers.