I work in a small group of about 10 people within my company. Every couple of months someone’s birthday comes up, and my boss and co-workers want to go out to lunch to celebrate. Each individual foots a portion of the bill. Though I enjoy my co-workers, I am uninterested in dining out with them. I have a history of very severe eating disorders, and these outings just cause a tremendous amount of anxiety for me, since I feel like I lack control. I would be much happier munching away on my lunch brought from home. I also do not wish to have my birthday celebrated in such a manner (or at all). Is there a tactful way to decline these outings without making it seem like I don’t like and appreciate my co-workers?