How about this:
There are many things that people can do to protect themselves from fatty liver disease or to reduce liver damage, such as losing weight in a safe way, which means not losing more than twopounds a week.
In the first sentence are no causes of the non-alcoholic steatohepatitis known? If so, then it's OK but if some are known and others unknown, I'd use 'can occur'.
In general, the occurrence of fatty liver disease varies of ten percent to twenty-four percent in different countries
This is unclear to me- does this mean that in some countries 10% of all people get it and 24% in the countries with the highest rate?
Student or Learner