The Daniel Fast is a plant-based partial fast. It is based on the Prophet Daniel when he was under the rule of Babylonian kings for their personal service. Daniel recorded three occasions of fasting, though he likely fasted many more times since he was a man of God.
Daniel 10:2, 3
Daniel 10:2, 3 is where we find the model for the 21- day Daniel Fast. From this passage, a guideline has developed over the years, primarily by Christians who use this as a form of fasting. The Daniel Fast has grown in popularity over the last 3 or 4 years
No Pleasant Food
This would include breads, sugars and sweet foods.
All animal products are restricted on the Daniel Fast. That includes meat, poultry, fish, and dairy products (milk, eggs, cheese, butter, etc.)
This restriction, coupled with previous fasts where Daniel drank only water (which is typical for biblical fasting), is where today’s Daniel Fast finds its roots for water only. Fruit and vegetable juices are acceptable.
“In those days I, Daniel, was mourning three full weeks. I ate no pleasant food, no meat or wine came into my mouth, nor did I anoint myself at all, till three whole weeks were fulfilled.” Daniel 10:2,3