Dieting and donating blood

I am in a biggest loser contest and trying to lose weight fast ($500 is at stake). I am on the Meditearranian diet and eating around 1000-1200 calories per day. I have also been doing about 40 minutes of fairly hard cardio or strength training 6 days per week. I started out 4 weeks ago at 224 lbs and I am now 211.6 lbs.   I have always donated blood on a regular basis and my next appointment is coming up. What type of food should I eat before I donate to keep my iron up? I haven't been eating red meat (but maybe this could be a good excuse if I control the portion).