which one is better?

[syed666]

run fast or run far?

[Paxiled]

Running fast is better for performance, running far is better for endurance.  Just do what you like, both are good exercise, but running fast gets the work done more quickly if time is a factor.  For me, I always liked running when I was still able to run and had no desire to get it over with too quickly, but for performance training, sprinting will make you stronger and more athletic overall.  Don't know about calories if that's your issue, as calories aren't that important for weight loss anyway -- how well you digest what you eat and your metabolism is far more important.  Another thing to consider is injuries -- running is high impact.  Sprinting is harder on the muscles, but long distance running puts a lot of strain on everything.  Your question is more complicated than it seems at first thought, so again, do what you like best if you're not in training for some specific athletic goal.

[gymdandee]

Not knowing if this is for weight reduction or not.
Fast or slow, you will be burning essentially the same number of calories per mile when running. The harder the effort, the fewer miles you will be able to cover, and the opposite is true. Your body tires of doing the same workout every day, no matter the sport. If you head out to run three miles every day at the same pace your body will slow its response to your efforts, and your weight loss and performance will likely plateau. Change your training up from day to day, incorporating fast and slow days into your weekly run plan, and your body will continuously respond to your training.
It's better to run 40 to 60 minutes three times a week, than 20 to 30 minutes six times a week." The longer training sessions help you to lose unwanted weight while building endurance and overall fitness. You can incorporate 40 to 60 minute runs into your training through long, slow distance or speed work with periodic rest breaks, and your body will respond by burning calories and losing weight.