Looking too skinny

Hi all, I'm a 44 year old male, 6'3" and weigh 86kgs after losing 16kgs with FB. I do the FB flex program as well as core exercises. Recently a work colleague mentioned that she felt I was losing too much weight and it was making my face look older. When I was younger I used to weigh 70 kg which was too underweight, not deliberately but,like now, my body just stayed at that weight. Could anyone offer any food options that I could consider to ensure I can continue working out as I am but not lose weight in the process? Thanks.