Can you donate blood if you are overweight?

Absolutely! But then you gain it back when your body produces new blood.

There is about 600 calories in a pint of blood. It takes energy to produce all of the proteins and cells in the blood. But because you can only give blood once every two months, 600 calories is not enough to make a difference. Try cutting 100-200 calories from your daily diet if you want to lose weight.