"Jesus Christ fasted for 40 days and 40 nights before he started doing his work. Gandhi used to fast all the time," Dr. Alejandro Junger, a physician who fasts regularly, told Sunday Morning correspondent Serena Altschul. "Fasting the right way definitely gives you a incredible surge of energy."
In an age of super-sizing, he preaches a much older custom.
"The Jews fast for Yom Kipper, the Christians for Lent, the Muslims for Ramadan," he said. "Fasting has been around for a long, long time."
In Southern California, some people fast religiously - even when they're not religious. On a remote desert strip is a spa where eating is never on the menu. Yet there's still a month-long waiting list just to get in the door.
Susan Lombardi is a co-owner of the We Care Spa, which her mother founded more than two decades ago.
"It's good for you, because it gives you time away from your everyday life," she said. "One of the reasons why we're here is to detox our system. And we are detoxing from things like pesticides and, you know, the white flour or sugars, the refined foods, all of those things that we put in our system."
You won't find those things in the We Care kitchen. Guests swear off solid food, but drink hourly from a list of liquid concoctions for days and weeks at a time. With a fast like this, you have to go slow. So guests meditate, practice yoga, and get mud massages.
"The longest fast that I've done was my favorite, was three weeks," Lombardi said. "It was amazing. I could go out with friends and go to an evening event and it would be like I don't really need to eat. It's not even tempting. We put so much emphasis on food. And I just went through 65 meals where I said, 'No thank you, I think I'll pass.'"
Not eating is an acquired taste and, like caviar, it doesn't come cheap. At We Care, people pay a lot of dough, but get no bread. The average cost per week is from $2,000 to $4,000 a week.
"Including, you know, the juices and teas, the stay, certain treatments and of course we have a full spa facility so you can add a lot more treatments if you like," Lombardi said.
New York gastroenterologist Arthur Talansky says fasting is against the grain of traditional Western medicine.
"I don't think God created us to fast," he said. "I think he created the intestinal tract to use it. I no more feel that someone should avoid eating, than I would say put your kidneys to rest by not drinking, or put your lungs to rest by taking shallower breaths.
"Just doesn't make physiologic sense to me."