Looks like I have it but not overweight and exercise regularly

I have been investigated for slightly raised liver enzymes for almost a year now and recent CT scan shows what looks like small areas of focal fat. My hepatologist is confident that it’s NAFLD and I am due to have a fibroscan soon.

I just don’t understand how I’ve got this when I am not overweight in fact I’m pretty much perfect weight for my height. I play football twice a week. I’m also not a drinker. My diet isn’t the best though I will admit and my total cholesterol is slightly above limit.

EDIT: should add that I’ve been tested for autoimmune issues all negative.