It sounds as though your question is really "do you really need to count calories to be successful on 5:2"? As much as it pains me to say it (I have always hated counting calories with a passion), I'm afraid the answer is "probably, at least at some point". Your friend may see some weight fall off immediately and get giddy (like I did). And then a couple of weeks later the weight loss will stall and some weeks even seem to reverse itself. She will get desperate for answers, blaming it on water, etc, but the cycle of gain/lose the same couple of pounds will become entrenched and if she isn't smart about it she will blame the diet and stop doing it. The answer will be that she is eating too much on feed days, simple as that. Some people on this forum (though the sense I get is it is somewhat of a minority) find a natural easing of the appetite on feed days because of the fasting. I ain't one of them (yet?) and it looks like many of us aren't.
It has taken me months to break the cycle I referred to above and it has only been by diligently entering the food I eat on myfitnesspal for the past week. Sometimes if I am eating something someone else has prepared I don't know exactly what has gone into it and have to make a "best guess" of the closest approximation. And the calorie counts on MFP aren't themselves always accurate. But it's better than nothing. On my feed days I haven't deprived myself of treats, but there is something about knowing you are going to see in black and white everything you have eaten that makes you consider carefully whether you really need it or not. On weekdays I have found it relatively easy to keep under 1700 calories and on weekends I let myself have around 2,000, and since last Wednesday I have lost almost 3 lbs (a lot of which, to be fair, was more likely to be water than fat). But I feel vindicated and motivated to continue some form of calorie counting for now. It isn't as much of a pain as I feared.
Hope your friend gives it a go, and succeeds!
It has taken me months to break the cycle I referred to above and it has only been by diligently entering the food I eat on myfitnesspal for the past week. Sometimes if I am eating something someone else has prepared I don't know exactly what has gone into it and have to make a "best guess" of the closest approximation. And the calorie counts on MFP aren't themselves always accurate. But it's better than nothing. On my feed days I haven't deprived myself of treats, but there is something about knowing you are going to see in black and white everything you have eaten that makes you consider carefully whether you really need it or not. On weekdays I have found it relatively easy to keep under 1700 calories and on weekends I let myself have around 2,000, and since last Wednesday I have lost almost 3 lbs (a lot of which, to be fair, was more likely to be water than fat). But I feel vindicated and motivated to continue some form of calorie counting for now. It isn't as much of a pain as I feared.
Hope your friend gives it a go, and succeeds!