Lose flab
Weight gain has been correlated with poor erections. Often reducing carbohydrates can be all that is needed to help reduce the worst kind of fat — abdominal fat. Cut out soft drinks, candy and desserts. Cut down or get rid of bread and pasta.
Source: http://onlinelibrary.wiley.com/doi/10.1111/j.1442-2042.2009.02426.x/full