Why can't we eat fruits during a fast?

We do not recommend eating fruit during the juice fast, as fruits contain fibre. During a fast, it's very important to not intake fibre. If you intake any kind of fibre during a fast, your digestive system will get activated and your praanshakti will get diverted into digestion, instead of healing. Drinking juice with fibre prevents you from gaining the full benefit of the fast.

However, once your fast has completed, you can gradually break your fast by consuming light, water-rich fruits. 

If you are doing a beginners level fast, then you may consume coconut malai/coconut meat during your fast.