I've only had experience on BR J around Asia, but I would not hold particularly high expectations. If you are going for "lacto-ovo", any lunch/dinner will likely be some sort of pasta dish with a tomato and vegetable sauce and the breakfast probably an omlet with potatoes and greens on the side. The meals will certainly be edible, but won't be memorable.
I've recently started ordering the Indian vegetarian meal on flights out of TPE (albeit in Y) and found it quite good if you like Indian food, definitely more flavor than than the standard vegetarian option. Usually a daal curry of some kind with bismati rice and a roti.