5:2 - kind of

How long have you been doing 5:2? I've done it before but I'm re-starting this week and today is my first fast day.

I've been losing approx 1lb per week by eating 1300-1500 calories on average (total including exercise calories) so probably netting around 900-1000.

On 5:2 I'm aiming for 2 x 500 calorie days (or up to 550 max) and on the other days I will continue to eat 1400-1500 as that's more than enough food for me.

In your case 1200 per day plus doing 5:2 seems far too little, though I don't know if you've been losing weight, how much you've been losing/how quickly and if you do any exercise or not.

I would think more about your total weekly calories and work it out that way.

For example I want to lose 1-1.5lbs per week so I know that to do that I need to eat around 1250 per day or thereabouts to lose 1.5lbs, maybe 1450 to lose 1lb per week.

That means that my total calories for the week shouldn't be any more than about 9,500 calories.

If I have 2 days of 500 calories and subtract that from the total then I am left with 8,500 for the other 5 days. This works out to 1700 per day, but I'll probably eat 1400-1500 for a little faster weight loss.

If you are only going to eat 700 x 2 plus your 1000 calories for 5 days you are only getting a total of 6,400 which is WAY too little. That works out to only 914 total calories per day if you split it over a week.

Remember you should be eating a minimum of 8,400 total calories in a week (1200 x 7) so if you want to have 2 days of 700 calories, take 1400 away from the total and you are left with 7000 to eat for the other 5 days.

The should mean you are eating no less than 1400 on each of the other 5 days as 7000 divided by 5 = 1400.

Yes, as others have said, it wouldn't be 5 at 1200, 2 at 500, but 5 at whatever your maintenance is (including exercise) and 2 at 500.

If you can't do the 500 days, probably best to just try the traditional deficit. Worked fine for me.