I believe that you should never comment on a persons weight and I don't believe that telling someone they have lost weight is actually a compliment. It's kind of like saying they were fat before? 😂 Sil called at Christmas time and DH told her she had lost loads of weight (she's not on a diet). He then looked at me and asked - don't I think she's lost weight? I felt so awkward and just said she's always looked lovely! So aibu to think that you shouldn't comment on a persons weight? I compliment people on having nice hair, clothes, a nice smile, eyes or personality traits, never their weight.