In addition to fasting on the month of Ramadan, Muslims are “recommended” (i.e. it's considered virtuous but not obligatory) to fast on Mondays and Thursdays of every week. That sounds eerily similar to the 5:2 diet in the article. http://en.wikipedia.org/wiki/Sawm#Days_for_voluntary_fasting
Muslims also know what's called prophet David's fasting, which is to fast every other day. However, considering that includes water, it's considerably difficult to maintain. I'm not sure I heard of anyone other than David himself do it for a long period of time! http://en.wikipedia.org/wiki/Islamic_view_of_David
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In addition to fasting on the month of Ramadan, Muslims are “recommended” (i.e. it's considered virtuous but not obligatory) to fast on Mondays and Thursdays of every week. That sounds eerily similar to the 5:2 diet in the article. http://en.wikipedia.org/wiki/Sawm#Days_for_voluntary_fasting
Muslims also know what's called prophet David's fasting, which is to fast every other day. However, considering that includes water, it's considerably difficult to maintain. I'm not sure I heard of anyone other than David himself do it for a long period of time! http://en.wikipedia.org/wiki/Islamic_view_of_David
A lot of the scientific interest in IF started with studying Muslims during Ramadan. I assume that is why it is similar.