The seminal fluid in men tends to be ‘watery’ and plentiful when a man is in his teens, twenties and thirties. The quantity gradually decreases along with age. The quantity tends to have direct relevance to the pleasure one gets during ejaculation / orgasm.
Of course, depending upon the extent to which a man gets excited and sexually aroused, the quantity of the seminal fluid can vary.
However, the type of food one eats can change the quality of the ejaculated semen. A man eating too much of protein tends to produce abundant seminal fluid . A drastic reduction in the protein quantity eaten can reduce the quantity, besides making the semen very thick.
Sperm production gets reduced in persons who suffer from long-term insomnia. A similar reduction tends to occur in men who keep awake throughout night, performing night duties.
Normally, all repair works, growth, productivity, etc. occur in people only while at sleep. Such works get disturbed in those who keep awake during night times. Therefore, a significant reduction occurs not only in the quantity of seminal fluid produced, but also in the quantity of red blood cells formed.
Thick seminal fluid may not be able to flow well into the cervix for fertilising the ovum. Thus, reproduction may get hampered if a man is going to refrain from eating protein-rich foods, or keep awake through the nights.
One should remember not to overeat proteins, for that would bring in several undesirable health problems to the person concerned.
In the under-urinating obese people, owing to the accumulation of calcium, the sperm cells become enlarged (hypertrophy). Their motility and capacity for fertilisation also become much reduced. This forms a major reason for the prevalence of sterility among the obese men.
See Salt Consumption, Hypersexuality, Obesity.