Launched over five years ago, the Sirtfood Diet is followed by celebrities throughout the world. To follow the sirtfood plan, you must choose foods that work by activating sirtuins. These play a part in influencing the body's ability to boost metabolism and burn fat. The result is a loss of up to seven pounds a week. Using sirtfoods within your favorite recipes is a lot easier than you may think, too. The plan is split into two phases. Phase one lasts for seven days and restricts calorie intake to 1000 calories daily for an initial three days. During this time, Sirtfood Diet founders instruct followers to consume only three sirtfood green juices and one sirtfood-rich main meal daily.