{"id":99,"date":"2013-04-30T21:00:43","date_gmt":"2013-04-30T21:00:43","guid":{"rendered":"http:\/\/joshmitteldorf.peachpuff-wolverine-566518.hostingersite.com\/?p=99"},"modified":"2013-05-04T14:48:49","modified_gmt":"2013-05-04T14:48:49","slug":"99","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/joshmitteldorf\/2013\/04\/30\/99\/","title":{"rendered":"Fasting on a schedule"},"content":{"rendered":"

Eating less is the best-tested and surest way to a younger body and an increased life span. \u00a0But it\u2019s a hard discipline to maintain, and many of us would welcome an easier alternative. \u00a0Perhaps we can realize some of the benefits applying a more temporary exercise of willpower, with intermittent fasting. \u00a0It\u2019s counter-intuitive, but seems to be true, that health and longevity are better served by clumping up our food consumption (feast and famine) than by spreading food consumption evenly through the day and through the week. \u00a0The topic is controversial, and the evidence is not just unclear, it\u2019s contradictory. \u00a0The bottom line is that it is worth trying. \u00a0Some people who drift away from diets involving consistent discipline find that they can comply on an intermittent schedule. \u00a0Experiment with different schedules, because individual response varies widely.<\/em><\/p>\n

The link between restricted diet and longer life goes back at least to Benjamin Franklin: \u00a0\u201cTo lengthen thy life, lessen thy meals,\u201d said Poor Richard. \u00a0Formal experiments on mice established the benefits of calorie restriction in the 1930s<\/a>. \u00a0But calorie restriction remained a backwater of research, unknown to most biologists, let alone the public. \u00a0Beginning in 1946<\/a>, intermittent fasting was introduced as an alternative lab regimen that required less measuring and monitoring. \u00a0These early experiments suggested great promise for cancer prevention and life extension by restricting access to food on various schedules. \u00a0This was exploratory work, and the experimenters were not keeping proper controls, or varying just one factor at a time, so it’s hard for us now to fit those results into the base of later experiments.<\/p>\n

In the 1980s, caloric restriction was already well-established as a robust way to extend life span, and alternate-day feeding and fasting was re-discovered. \u00a0\u00a0In the best outcome<\/a>, rats lived 83% longer when fed every other day. \u00a0Looking back from today, we would want to ask: \u00a0how much of that benefit came from lower consumption overall, and how much from the schedule and periods of fasting? \u00a0Did they eat much less overall? \u00a0Or did they gorge themselves on the in-between days and make up for lost time? \u00a0Though no records were kept of the animals\u2019 food consumption, the results seemed to be too good to be due to reduced calories alone. \u00a0The schedule seemed to be at least a contributing factor in the success of the diet.<\/p>\n

Some species are adapted to graze continuously, while others have a much greater capacity to store food and digest it slowly. \u00a0\u00a0Even within the same species, different varieties may react very differently to alternate-day diets. \u00a0A study by Goodrick (1990<\/a>)\u00a0highlighted the different responses of two strains of mice. \u00a0Both were put on the same every-other-day regimen. \u00a0Both maintained their body weights, with no significant differences from control animals fed ad libitum<\/em>. \u00a0But one strain enjoyed consistent life extension, and the other suffered a slight decrease in life span from EOD feeding.<\/p>\n

Experience with people<\/strong><\/p>\n

People have a hard time adapting to no food at all every other day, so the four regimens that have been suggested for humans are<\/p>\n