It's primary a function of time preferences. Ceteris paribus, men prefer things that can be consumes right now rather than later.

Everyone knows that exercise is good for you, credit card debt is bad, etc. However, most people succumb to shot term temptation, rather than long term gain.

It is like the marshmallow experiment conducted by Standford university.(http://www.newyorker.com/reporting/2009/05/18/090518fa_fact_...)

Most kids succumb before they can get the second marshmallow. However, those that wait these long few minutes will get two of them.

If a man will have a low time preference, in general, he will be more wealthier than a man with a high time preference.