I'd say if you want to know if you have an ego try not sleeping with your wife or wanking and watching porn for a month and watch the excuses and shadows appear thick and fast.
If anybody doubts how Gandhi got hundreds of millions of followers by the time of his death look no further than palate control and abstinence from sex.
It seems to me it's the one thing everybody isn't doing. People are doing marathons, climbs or whatever but as soon as it comes to facing down your own ego with abstinence I'd guess people would rather climb K2 than fast for 24 hours let alone longer. I found the biggest problem when I did this was not hunger pangs but my mind trying to feel sorry for itself and I had to keep saying I'm doing this for positive reasons.
Also, quitting alcohol turned my life around in some ways. I couldn't see it but read that the Kabbalah said your powers are locked in your addictions.
I read about Gandhi, in his autobiography, just seemingly casually doing a 3day fast out of mistreatment of workers on one occasion. I mentioned to somebody I was fasting when he asked why I wasn't eating and within two weeks several other people did a fast and announced it. Coincidence? Maybe.
It seems that palate control, fasting and abstinence from sex are two of the most powerful things a human can do.
So I was going to experiment with a 24 hour fast one day a month for the next year. Do you think people would give money for fasting for charity? Would you, personally? Any positive comments, ideas would be welcome.