This is one of those I considered too ridiculous to even rationalize; it's in the "because why not" pile.
First try: Cut the TV, read rss feeds or email while eating. Baaaad idea, obviously. Not only was I still feeling guilty because 'without eating you would read much faster' but I also degraded eating to something even less valuable. There was zero relaxation, I didn't even really _taste_ what I was eating.
Second try: I dismissed TV, rss feeds and everything else while eating. Eating now is my 30-to-60-minute-break of everything 2 to 3 times a day. I just concentrate on preparing and eating the food. I even started to eat in my kitchen again and not on my couch or in front of the computer. Makes a hell of a difference.
I'm so much more relaxed after these breaks. Often I will stay a little longer and read a magazine (brandeins, a german business magazin) or even a book.
PS: Next step is to go out for eating every other day to get some sandwiches, pizza or something. It's a bit more expensive but really helped me to really get away from everything in my head.
PPS: Of course I sometimes still sit over my keyboard with a pizza and work while eating, but well, I never said I was perfect ;)
This encapsulates exactly how I feel most of the time. It's really hard for me to get past the guilt of not working on the startup. Even things like eating breakfast in the morning, I don't want to do because I feel like I'm wasting time, so I end up starving myself until lunch.
It's weird because it one of those things that you KNOW you shouldn't do, yet you somehow find yourself in that downward spiral.