Fluctuating ALT level

Hello. I am a 34 yr. old male, somewhat overweight, and have had three blood tests over the past year due to elevated ALT levels. The first test revealed ALT of 78, the second, about 3 months later was 42, and the most recent showed the level back up to 92. I drink less than six beers per year, and only take ibuprofen for recurring headaches. I have completed a hep-screen which I'm awaiting results for. My weight is up to 230, which is higher than my normal 220. Cholesterol is also elevated. I'm aware that I need to see the results of the hep screen, but feel fairly certain they will be negative. I'm also aware that there are many causes of elevated enzymes, but I wanted your opinion about the possibility of NASH and any treatment. Thank you.