Massive Weight Lost - Calorie Shifting?

On Wednesday after the Calico race, I got sick.  I was coughing, had a fever, my body ached, I tried to vomit, and my head felt like it was going to explode.  I caught the flu that's been going around, complete with the "works" of symptoms. Needless to say, I couldn't run for a few days. More exactly, about 5 days. So, since I couldn't run or do any exercise, I figure that I should cut back on my food intake. This was not hard to do at all, since I was sick and had not much of an appetite. I was eating sparingly but I didn't exactly starve myself. At no time did I feel hunger pains. I ate the same way I was eating, but just reduced the intake by about 70%. However, I did start to eat chicken noodle soup, which I normally don't eat at all.

Now, this is going to sound unbelievable. And, I know people are going to say that it is impossible or even unhealthy, or that there is something wrong with me medically. But it is really what has been happening to me. Since last Wednesday, I've lost 6.4 pounds in the span of 8 days. That's 0.8 pounds per day; and that's amazing. I know that losing a lot of weight very quickly is not necessarily good, so I tried to see if the weight I have lost is muscle or fat. I figure that if I can run like I did before and still feel strong, then it must not be muscle; and, therefore, it must be fat. Well, so I started running again and doing my core routines for about three days now. The first few miles on the first run after 5 days not running - I felt a little stiff in the legs. Then the muscles came back on line. I now feel as strong as ever on my runs; and I feel like I'm running even faster because I have lost some weight. And doing the core routines feel great too. I'm doing the same reps and sets as before and I'm not tired afterwards. I have to conclude that I have lost fat and have dropped my body fat percentage a few clicks. I now have better power-to-weight ratio.

You may ask: how much and what kind of foods exactly are you eating the last few days?  So, here's a typical day:  I start at 5:00 am with a cup of coffee, then I eat a scone at about 8:00 am, just before my first run.  Then, I come back from my run, and eat my breakfast at about 9:30 am.  I have been eating salads and chicken noodle soup, and sometimes some pita bread, spaghetti, fruit sorbet, or some red meats. The breakfast is not big, but light at about 400-500 calories. Then I eat a late lunch at about 2:30 pm, usually the same fare as my breakfast.  Also, at about 400-500 calories. Then I eat another scone just before my second run at around 7:00 pm.  After the run, if I feel hungry, I eat another 200-250 calories; if I don't feel hungry then I don't eat until the next morning.  The runs have been from 5-7 miles, and my total calorie intake per day is about 1500.  This is the same routine that I have been using for the last few months.  I have never lost this much weight this quickly, not that I'm complaining :). The most weight I have lost was probably 1-2 pounds per month. 

I really have no idea what has been happening. I have some conjectures. First, the flu somehow made my metabolism speed up.  Second, calorie shifting. I did some looking around on the Internet for cases involving sudden massive weight lost and I learned about something called "calorie shifting". What it means is that you purposely change the kind of foods you eat periodically to avoid metabolic slow-down when eating low calorie diets. Of these two theories, the second one is more likely; but I don't really believe any one of them have full merit.  In any case, the weight lost happened when I got sick, or when I had a sudden change in my routine. Go figure.

If you have some ideas about what has been happening to me, please post comments...