Drink plenty of water throughout the day. Although the fruits and veggies in your cleanse contain water and the juices are liquid, many people often forget to drink plenty of regular H2O during their cleanse.
When a body isn't getting enough water, it will be more tempted to hold onto the water inside of it - this is what is known as water weight and what can cause the number on the scale to climb. Along with regular H20, you can have as much tea (green and herbal) as you like.
This will keep your energy levels up and prevent crashing and/or headaches.