As winter turns to spring we become more active. There is more sunlight and more qi available for getting things done (whether we exercise more or not). As the weather warms we also eat less. The combination of eating less and being more active actually slows down our digestion/metabolism.
Thus, toward the end of spring people start feeling overworked and stagnant, they want to "detox."
The Daoist approach to Spring is to conserve while simultaneously taking advantage of the extra qi available. Ones diet should have lots of watery soup, lots of liquid, fresh greens. Less grain, smaller portions of meat, fruit only between meals. But it is still important to eat enough food for the type of activity you are doing. Then go to bed early.
It's not the season's fault that people have problems, and it is not really the type of food or how much. The problem is that people want to stay up late, they skip their afternoon naps and party right on through.
What most of these fasters and liver cleansers have is a miniature version of anorexia. But don't get exited. To paraphrase the Daodejing: It's not that people get dealt a bad hand, it's that they take a situation of excess and make it more excessive; they take a deficient situation and make it more deficient.
Already strong vigorous athletes, sign up for Iron Man Triathlons. Skinny people who aren't hungry, decide to fast.
There is nothing new here. Spring festivals everywhere are some version of dancing and drinking all night and waking up in the bushes with somebody else's partner.
After a night like that, purification is sure to keep you on the roller coaster road to redemption.
When you fast for 10 days you may drift in and out of transcendent bliss, wandering, day dreaming your way through conversations. By the end of 10 days your sense of smell will be heightened as will your sensitivity to breezes and changes in light. You will be prepped for doing exorcisms. Even the subtlest ghosts will be brought out of hiding--by your acute weakness--where they can be captured or transformed. (Ghosts are unresolved commitments which linger because they don't have enough qi to move on.)
Kids this time of year scream more. They also beg for food. They can't seem to stop talking and they "accidentally" chop, punch, and crash into each other. So that's my seasonal advice to all of you.
Cleanse your liver with loud sounds, laugh, sing, grunt.
Make yourself eat enough. Of course, don't over eat! But don't try to get through the day on a granola bar and a cup of coffee just because there seems to be enough qi "in the air."
And if you practice gongfu, get a little rougher. Make those "accidental" slaps sting. Then take a bath and go to bed early.
After thought: Sometimes people who are overweight from too much rich food in the winter, try to lose weight with a "liver cleanse." If you are really taking off a significant portion of weight through purging and fasting, you are also putting your heart at risk. This kind of up and down with your weight every year will likely shorten your life. Do it once; then use extraordinary discipline throughout the year to make sure you don't gain the weight back again.