I started on the 5:2 diet on March 11, 2013 (4 fast days so far), after being told about it by a colleague. I have been a pescetarian since April of last year (I don't eat land animals, but do eat eggs, dairy, and seafood). I also travel for work, although haven't been doing so for much the last few months, which makes it easier to start out a new way of eating. I don't expect this to continue though.
I eat a pretty healthy diet. I eat very little in the way of processed foods, don't eat much sugar, never drink sodas, and avoid HFCS like the plague. I'm 5' 4", and am 50 years old. I have been gaining the stereotypical 10 lbs per year up until around 2009. Then I became a traveling consultant and my weight ballooned by 10 lbs very quickly with all of the restaurant eating. I had been maintaining at 145 lbs for quite a while, and was suddenly at 155 lbs, and I hated it. I lost it all during a very stressful period leading up to my divorce in 2011, but have gained it all plus a couple since then.
My normal caloric intake is not enormous. I have very little to work with in terms of daily calorie reduction. So when I read about this diet, it appealed to me because I knew I could easily eat little for two days a week as long as I didn't have to feel as if I had to stop ingesting anything good for the rest of my life. Also, I have fasted before, and have found it much less difficult than I expected. Planned hunger has a very psychological component. If you know you will have plenty the next day, it isn't really a big deal (at least for me) to do without for a day.
I've been on it for two weeks now. My weight fluctuates by 1 - 4 lbs daily, so it's difficult for me to know in such a short period how I'm doing. However, I hit a low of 152.7 a week ago, and I know I haven't seen that low in over six months. So, I feel that I have probably lost at least two lbs of actual weight at this point. So far so good. I don't see any downsides, really, and only pluses, because the health benefits, outside of the weight loss, seem to be pretty conclusive. I do hope to at least get back down to 145 lbs. If I do, I will probably set a new goal of 140 lbs. But I will at least not have such a poor body image at 145 lbs.
Sabrina