On my fast days I tend to start with a bowl of porage: 1 cup of oats, water, salt, maybe a splash of (semi-skimmed) milk. Black coffee, water to start off with (vitamins, etc. to swallow). I forego my usual orange juice, no milk in the coffee.
That's approx. 300-350 calories.
That keeps me going until lunch where, instead of skipping it entirely, I generally have a hard boiled egg.
70-80 calories.
I find this, plus black coffee, black tea, and one or two cups of Bovril (20 calories each) mean I manage to last until dinner time.
Dinner is usually a chicken berate or some grilled fish, with steamed broccoli, cauliflower, or cabbage. Occasionally there'll be something else like strips of carrot in the mix.
That's around 250-300 calories.
So I'm up to 650+ already on a bad day, lower if I manage to keep the portions in check..
I then have the tricky later evening to deal with. Yes okay going to bed early is an option, but not always feasible. So this is where celery sticks, the odd handful of nuts, etc. starts coming in. That's the danger zone for me…
Also sometimes my wife prepares food for me, as she likes to eat healthily. That's very nice, but she tends to fry the chicken or fish in olive oil, then chuck the veg in to stir fry it… Add on a dollop of extra calories!
