Why might my liver enzymes be enlarged when i am otherwise fit and do not drink alcohol often?

VARIES : Varies, but it could be gallstones, hepatitis, even dehydration. Talk to your doc and work it up.

Find cause: Something as simple as taking Ibuprofen can raise them. Other possibilities include being an extreme athlete, having hepatitis b or c on board, having hemochromatosis or wilson's (don't miss those) or despite your fitness level having metabolic syndrome.