Loosing Weight

Hi and welcome,

I assume your weight loss isn't deliberate and has no obvious cause? If so, rather than try to gain weight, I would go to the doctor, tell him your worries, and ask for the relevant tests to check you are actually type2 and not LADA. (latent autoimmune diabetes in adults) The tests you need are a C-peptide test and GAD antibodies test.

Hi @nirazwagle and welcome to the forum. I don't think you would be thin if you are 64kg and 5'6". I am 63kg and 5'7". Your Body Mass Index would be about 22.7 which is around the middle of the 'healthy' range. The NHS guidelines are that for an adult male of 5'6" the healthy weight range is 52 - 70.5kg.
If you want to put on a bit more weight you could try eating more healthy fats like nuts and cheese.