>>40411049 (OP)Lowest semen calories estimate:
If we assume each man can only cum once a day and we use the lowest estimate for calories in a teaspoon of semen (5 calories) you would need 400 men to reach 2000 calories (assuming we ignore nutrients you'd miss)
Meeting your daily protein requirement:
The amount of protein needed varies depending on your weight however we'll use 50-175 grams of protein for this question.
1 teaspoon semen contains 252 mg of protein
which means to get 50 grams of protein you need ~198 men and to reach 175 grams of protein you need ~694 men