An enormous study but after mailing 3.5million people they were left with an analytical sample of only 536 969. That can't be good. Also all the usual problems of measuring dietary intake. This would be a good study to practice your critical appraisal skills.
On the other hand, if I gave up red meat I wouldn't miss it, especially since white meat is ok. Except for tagliatelle bolognese - I would miss that.