Ember wrote: I have a single cup of Marigold Vegetable Bouillon if I feel like it (but it is so low in calories that I haven't counted it as a snack or lunch). But I don't have this every fast day, and I would only have only one mug per day anyway. I have miso soup in the cupboard in case I should ever become desperate and feel like a change.
Apart from that, I have just a large bowl of homemade vegetable soup in the early evening. This means that I don't have to count calories at all, even on a fast day, as a few test calculations showed that it is probably physically impossible to eat 500 calories' worth of vegetable soup if you don't add fat or starches other than the occasional parsnip or single potato (for the entire pot of soup, to help thicken it). Stick to lower-starch vegetables and add no fat, and you get a really low calorie soup, which is very satisfying if you blend it until it is smooth and velvety. My first couple of batches (which I did count carefully) came in at 100 calories or less per serving.
As evidence to support my theory, have a look at http://www.bbcgoodfood.com/content/recipes/healthy/low-calorie-soup/ which has a range of soup recipes including much more calorific ingredients than I use for my fast-day soup, all coming in at under 200 kcal per serving.
So I think I have a plan that suits me now, in which I don't have to count calories at all, even on fast days. I like to think that there is precedent for fasting like this, in mediaeval monasteries!
Fabulous site! thanks for that. Gonna dart making these soups for fast days