The first time I made this loaf, I forgot to add in the half cup of oil specified in the recipe. I did not even know till I looked at my newly opened bottle of olive oil sitting on the kitchen counter and it struck me that it had not gone down in volume! I was dreaming while baking :p It was a tad dry but was still very delicious because of the strong orange flavour and crunchy walnuts.
I made this loaf a couple more times after that because my hubby and kid love the orange-y walnut combination. I substituted the olive oil with low fat yoghurt to reduce calories and because yoghurt would add moisture to the loaf in the same way as oil.