How many miles should I run in a week to lose weight fast?

Exercise is great for toning and fitness but it just doesn't do anything for weight loss UNLESS you also control your diet. Weight loss is 85% diet and 15% exercise. If you don't control your diet you'll just get hungry and eat more. You could put on considerable weight.

So there is no answer to "how many miles". It's more about "what you eat".

You should eat plenty of non-starchy vegetables - green beans, broccoli, brussel sprouts, cucumbers, lettuce, cauliflower, asparagus, carrots, kale, etc. Ten plus serves per day.

You should also eat adequate protein and good fats - grass fed meat, fish, eggs, cheeses, nuts & seeds.

You should NOT eat any sugars or starchy foods - potatoes, rice, bread, wheat, flour, pasta, etc. This is a totally DO NOT EAT.

You can slip in fruit occasionally, but no more than one per day.

If you can do this diet you can eat as much of it as you want. You're very unlikely to be able to eat too many calories. You will have an abundance of nutrients. And you will feel full and you will lose weight (fat) in the fastest way possible. Exercise is recommended but it is optional.

I swim 3 miles a day. You can do better than run 3 miles a day.

just do the best you can! you will work you way up to longer distances.. start small then go big

but you have to eat better too! eat clean, check out the fitspo community on tumblr its really great! you can check out mine if you want.. its peanutbutterrhealthy.tumblr.com

sugarless chewing gum can suppress your appetite in a pinch

walk before dinner and youll cut calories and your appetite

stand while waiting for a train

pack healthy snacks

ditch half of your spaghetti for spaghetti squash