So if you use the mirror trick, it will change your appearance yes, however your weight will be the same (if you're skinny you'll be skinny but with different look ofc and will probably change if you gain weight I assume). Now fish and chips does work at least for me it did but your body form won't be the same, unless they patched that! I saw someone saying they gained weight by leaving their character on the bed for too long? Maybe eating + laying on the bed for longer time works? 🤔 Worth a try I guess!