According to the Re/Search Guide to Bodily Fluids (Paul Spinard, 1994), the average man produces about 3.5 mL of semen per ejaculation whose nutritional value is less than

1 calorie
150 mg. protein
11 mg. carbohydrates
6 mg. fat
3 mg. cholesterol
7% US RDA potassium
3% US RDA copper
3% US RDA zinc
300 million spermatoza

(Someday men will have to have all this tattooed to the side of their hip, like a can of Coke or a box of Wheaties.) It looks healthy enough per serving size, but when compared to breast milk (which has about 170 calories per cup), semen has about 40% more calories (about 230 calories per cup). High levels of fructose (fruit sugar) is normal in the semen and this sugar comes almost entirely from the seminal vesicles.

More Fun Sperm Facts
For the average man, the ejaculate contains over 80 million sperm.
Average volume of semen per ejaculation: 1-2 teaspoons
Average number of times a man will ejaculate in his lifetime: 7,200
Average total amount of lifetime ejaculate: 18 quarts
Average speed of ejaculation: 28 miles per hour
Average duration of orgasm: 4 seconds