I used to donate all the time (was a member of the "10 gallon club"), but now that I'm not in the corporate world anymore and the vampires don't come to me, I haven't made the effort to go to them in quite a while. A high protein meal before donating used to get me through it. I found if I ate only carbs before and/or after, I would get weak. The cookies and juice would raise my blood sugar too fast and I would feel sick all day.