I met a friend at the weekend I haven't seen since Christmas and she's lost loads of weight and looks fab. She gave up alcohol except on Saturdays, upped her exercise a bit AND - this is the controversial bit - one day a week she eats nothing but raw fruit and vegetables and another day she eats nothing and only drinks water. The other days she eats normally. I think I could go for this - what do you think? ( she doesn't exercise on the no food day)
I take quite a hardline (with myself) when it comes to weightloss. You just have to put less in your body than you use up, regularly. Which means that over the whole week, your friend is still consuming less than she is spending. It might be worth asking her for a food diary and exercize plan. Cos her 'normal' eating might not be 'normal' to you. And she could be a exercize junkie like me.
There are lots of diets like your friend does - how it works is that you are drastically reducing your calorie intake on those two days, the rationale being that no matter what you ate on the other five you wouldn't make it up.
the nutritional reasons behind diets like these are that you are drastically reducing your weekly calorie intake and the body gets 'used to' a certain amount of calories each day and adjusts itself accordingly to be more efficent. so if you take in a drastic amount of calories for three days your body will get used to burning/storing that amount of calories and will adjust your metabolim accordingly. if you suddenly eat nothing the net day your metabolism will still be working at yesterdays rate and will need to burn off fat for fuel. but go too many days without food and you will go into starvation mode and your body will store every bit of fat you get and burn muscle for fuel instead. unless however you are using that muscle <that is where the exercise comes in>.
they do work and dont really cause as much damage as you would think. but it does depend upon how much you exercise <so that your body doesnt burn muscle instead of fat> and how much you eat on the other days would still need to low enough to ensure your weekly calorie intake is lower than that of which you burn in energy per week.