I would just like to summarize my experience with the 5:2 diet so far.
The diet is supposed to bring many health benefits, weight loss and maintenance being just one part. This part is however important for me, so I chose to give it a go. I expected to get a better grip of portion sizes (by seeing how small portion can actually be enough) and to practically learn that occasional hunger does not present any danger. Furthermore I though that such system may somewhat simplify my food preparation routines.
Well, so far the journey has been quite surprising.
The biggest surprise is that it is actually very easy to stick to 500 kcal. When I choose my fast-day meals wisely, meaning lean foods with high protein content, and I use some extra fibers (such as psyllium husk), I don't even notice I ate only 500 kcal.
Another surprise is that I don't feel any urge to overeat on the non-fasting days. I may actually be eating even less calories those days than I ate on average before I started with 5:2. It really makes me understand that "the food is going nowhere" and that there is therefore no need to eat everything now. That is very good.
The weight loss came as a surprise too. So far (2.5 weeks) I lost 2.5 kg. The largest drop occurred during the first week, I suspect I was retaining some awful amounts of water.
I got also surprised by the elevated energy levels with my energy being extra high on the fasting days. This is described in literature, but who believes that without trying, right? :) I find it easy to both train and to concentrate on fasting days.
So far so good...... as long as the high energy occurs during the active part of the day, it makes the fasting day quite a pleasant experience which I am actually looking forward too.
However, and here we are getting into the less pleasant part, the elevated energy levels can disturb the sleep. Again, a known, described effect, which however caught me unprepared during the very first week. After my first fast day, I did actually not fall asleep at all
The second fast day was ok, the third I had again some hard time to fall asleep, but finally I managed. Fasting days 4 and 5 were completely fine.
Last but not least, the day after my first fasting day I experienced quite a proper diarrhea. This has not repeated itself after any other fasting days.