Excellent post and an important topic.
It's common in many discussions on self-defense for people to promote "running away". And it's the best option IF it is a viable option, but that's not always the case.
People will promote "running away" for various reasons. Some people consider themselves ABOVE using violence, they promote running instead of fighting as the "civilized" thing to do. Some consider "fighting" to be the response of juveniles, and promote running as the "mature, adult" thing to do. Some are afraid of the possible legal consequences of fighting, they consider "running away" to be the "legally safe" thing to do. Many will simply parrot what they have heard others say regarding "You should always run. Running is ALWAYS the best thing to do".
Me, I advise running when running is the right thing to do. Contrary to what many believe (like those I've mentioned above), running is NOT always the right thing to do. I consider it the WRONG thing to do when you decide that it has a clear likelyhood of failure and good chance of getting you killed. As far as "when is running the right thing to do?", that's something that can only be determined by an individual, at any given time, in any given situation. And there's really no way of knowing in advance, with certainty, if it will be the right choice.
For the sake of discussion, I can think of numerous very real reasons why running would be either impossible, or dangerous.
What if you are incapable of running? Sick, asthmatic, elderly, handicapped, injured, overweight.
What if you aren't a track star? Who's to say that the criminal isn't a faster runner than you. I did time with a lot of criminals who put a lot of effort into keeping themselves in TOP physical shape. I watched a lot of inmates run A LOT of miles inside. Believe me, unless you are in GREAT running shape, there are MANY criminals who could catch you.
What if you are wearing dress shoes or other footwear not well designed for running at full speed?
What if you are with companions who can't run? Elderly, handicapped, overweight, not in great running shape, etc. Would you just say "Tough luck, you're on your own, I'm outa here".
What if you are with your wife or girlfriend or children or a combination of such?
What if you are walking your dog?
What if you don't know the area? It could be very easy to run yourself into a dead-end. It could be very easy to box yourself in. Then what?
What if you are attacked indoors or in a confined space? Like perhaps when you open your car door to get out, or after you've just gotten in.
Did I miss any?
Like I said, running is an excellent option, WHEN it's an option. But that's not always the case.
Congratulations Kenny on losing the weight. Good luck in your continued efforts.