I am testing out a theory. I believe we are biologically programmed to have periods of feast and famine. Our early ancestors would get lean and hungry. They would kill a mammoth, and everyone would gorge themselves until the mammoth was gone. And then it would be famine again, until they could kill another mammoth.
Last week, I went on vacation, and I "ate a mammoth". Lots of wonderful restaurant meals, large breakfasts, desserts, vodka, beer, more beer. That was phase I of my experiment. On Sunday, when I came home, I weighed in. I had gained 5 pounds in my week of excess.
Now I am in Phase II -- famine. I am eating a very lean, very healthy diet of 1100-1200 calories a day. I lost a pound and a half on Monday alone. If I am back to my normal weight in 7 days, I will feel my theory holds water.
Once in a while you have to eat the mammoth.