Tailor the above recommendations to your personal needs and lifestyle. If you’re a vegetarian drop the bacon and steak, but keep the whey protein and eggs. If you have an injury that prevents you from heavy weightlifting, move as much as you can in the way that you can. There are no studies out there which can tell you exactly what will happen if you do X and Y, but not Z. And I certainly can’t tell you either. Don’t be afraid of self-education – that’s how I learned all this – and embrace the idea of conducting your own experiment and being your own test subject. Incorporate as many of the recommendations above as you’re comfortable with, consult your doctor, and track your results.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.     
I tried the cup of raisins before bed and woke up before dawn with an erection reminiscent of days gone by, that lasted for over an hour. Pretty awesome! Though peeing was a long and drawn out affair.
I just had my T checked as I was not getting them any more, neither was I much interested in sex. The test came back with a paltry 305 @ 46yrs old. Just a year ago my erections used to have a bitter sweet ache to them. After going close to zero carb I lost my power, my head hair, got rosacea, limp erections, and my nitric oxide plummeted. I stopped training as it was painful and although I was eager to exercise my body just didn’t seem up to it. ( come to think of it now after reading all these articles, it would seem that lower elasticity of my arteries(low NO) was the reason.)