Wow, that’s interesting, but not surprising. Are all your friend’s females? If so, they may be modeling your friend’s unhealthy eating behaviors.
Is it a call for attention? Well losing weight usually does get a person attention as does gaining weight or other changes in a person’s physical appearance. As to whether this goes beyond temporary dieting or becomes a preoccupation with thinness, food restricting, and a distorted body image, that remains to be seen as you continue to eat together. Your lunch friends may make up the calorie difference at other meals or when other people are not present. However, if these friends start looking too thin, they will need professional help as your friend who has anorexia.