There is a mention of fast in Mahabharata, Anusasana Parva about fasting which is continued for twenty eight days, which is the maximum days of fasting.
That man who having fasted for eight and twenty days eats a single meal on the twenty-ninth day, and bears himself in this way for a full year, adhering all the while to truthfulness of speech, attains to auspicious regions of great happiness that are worshipped by celestial Rishis and royal sages.
My question is, are there any diet plans for fastings which may be prolonged for such long days in scriptures. Are there any books which deals with such diet.
If there are any references that these type of fastings are valid for Dwapara Yuga only, then what is the diet plan for fasting for maximum number of days that is allowed in kaliyuga.