Moderate to heavy alcohol consumption can raise estrogen levels in men.
Your body may not raise your T levels naturally to balance your hormone levels out.
Weight gain and man boobs could indicate high estrogen or low testosterone levels.
The study of "andropause" or male change of life is really still an emerging field and there aren't a lot of good studies or hard facts.
One fact is true though, as men age testosterone levels often drop. This can cause low energy, weight gain, man boobs, poor muscle tone, depression, sexual drive or performance issues and prostate problems just to name some.
Testosterone in the correct amount and properly balanced with the other hormones is for all practical purposes our fountain of life.