This quite contrary to what all fasting experts say. As soon as you put any food item in your mouth, your digestive system gets active thinking the food is coming in, but then it does not. This leads to starvation. I rather clean my tongue and mouth with water and scrape the tongue with tongue scraper. I am on my fourth day and I have very little smell from my mouth because I am scraping my tongue every three to four hours a day. This way I also pull a lot of mucus from my throat.
I love oil pulling, but not during the water fast.