Monday- This is the day of the week, which is ruled over by the Moon[Chandra]. Hence it is considered beneficial to consume foods that contain plenty of water or fruits like like watermelon, pumpkin or cucumber, which will enter and nourish the body and meet its essential requirements.
Tuesday- Fruits like Mangoes and Pineapple are considered to be beneficial if they are a part of the diet on Tuesdays.
Wednesday – Any kind of food can be consumed on this day.
Thursdays – Yellow or Orange colored foods and fruits like oranges, bananas or lime are beneficial if consumed on Thursdays.
Friday- Like Wednesday any kind of food can be consumed on Fridays.
Saturday – Saturday is as per astrology the weekly day of Saturn [Shani], hence foods containing plenty of oil or oily foods cannot harm the body on this day.
Sunday- This is normally the weekly holiday, hence time can be devoted to food on this day. Leafy vegetables, fruits, meat and other non-veg foods can be consumed on Sundays.
Note- There are likely to be many variations of this Tantra based upon the diverse religious and Tantrik practices and also foods habits prevalent in most parts of India.