Sorry to hear that @Ztauqeer.
Things like weight gain are really difficult to address because there’s no magic pill or diet that will work for everyone all the time. There are so many factors affecting it (diet, physical activity, sleep, mental health, gut microbiome, other metabolic conditions, genetics…) that it will almost necessarily be a long series of trials and experiments. What’s also important to know is that these measures take a long time to see change, so whatever modifications you implement need to be incorporated into your life for years, not just crash diets for a few weeks.
There is discussion here about it: Lifestyle changes, nutrition, and supplements for hep b
Hope that give some context.
Thomas