What calculator are you using? 1000/124 = 8
Eight miles is more than a couple.
Eight miles is more than a couple.
At a leisurely 10 minutes per mile, that's 1.3.. hours of running. Well, overeating by a thousand calories is a lot.
But even assuming you burned 0 other calories, still, the argument holds.
You can, indeed, get thin by exercise.
If one stubbornly insisted on ONLY getting thin by running, and steadfastly refused to take responsibility for what went into one's piehole, STILL -- it would be possible, if perhaps impractical, depending on just how irresponsible one's eating habits were and how much free time they had to exercise.
But plenty of people get up early enough, for instance, to run for an hour. So it's not only doable, but EMINENTLY doable.
The obvious solution is cross-training, but there aren't many things you can do by yourself that burn calories as well as running.
All activity's at your aerobic limit burn the same number of calories. You can run, dance, row, weigh lift, or just bail hay, and you will encounter the same limit. It's basically a question of how much oxygen you can absorb though the lungs and dump into your blood stream.
And, if you'd prefer, get on a bike for an hour instead. It's lower impact, and you'll burn at least as many calories as running.
I'm not an expert, but I read what they say. This is way, way out of line with what any experienced running trainer would tell a beginner. Not even a beginner who was, say, an extremely fit swimmer. Definitely not a sedentary beginner. You have to give your connective tissue time to adapt to the peculiar stresses of running. (Plus, beginners are going to have crappy form and inflict more punishment on themselves than necessary.) By the numbers most people use, it would be very aggressive, but possibly reasonable for some people, to ramp up to 42 miles per week in one month from a base of ~29 miles per week or in two months from a base of ~20 miles per week. And that's pretty aggressive. Trying to get to 42 miles per week in two months from a sedentary state would leave basically everybody injured except genetic freaks or people with a previous adaptation to high-mileage running.
If you're starting from a sedentary state with no weight problem or existing injuries, you might start with eight miles per week and ramp up to 42 miles per week over nine months. That's a 10% increase in mileage every other week, and it assumes you don't screw up and get hurt, which many beginners do.
And, if you'd prefer, get on a bike for an hour instead. It's lower impact, and you'll burn at least as many calories as running.
That might be more reasonable (if you can find someplace nearby where you can ride in a fast, sustained way without blowing through stoplights or terrorizing pedestrians.) I don't have personal experience with ramping up bike training (I just ride to work once in a while) but from what I hear it doesn't require as much care as running.
The human body really is designed to run. Most injuries are due to pushing to go too fast. If you keep your heart rate at about 60-70% of max, you'd be surprised how quickly you can ramp up mileage without hurting yourself. The key is to never push yourself so hard that you feel like you couldn't do a workout the next day.
Cycling works almost as well from a cardio-vascular standpoint, too. It's not weight-bearing, though, so it won't help improve your bone density or strengthen your joints like running will. You could probably compensate by doing a bit of weight training. In the end, it comes down to getting off your butt and moving.
Over short distances maybe, but longer distances? Your modern western person isn't even setting enough time to do 20 minutes of exercise per day let alone moving a 10 minute mile. To move this speed for periods of time requires serious effort. As for injury well it depends how far, how long. I know, I've been doing 10Km on a regular basis for 770Km this year across a cross-country course and I'll tell you now, moving at the speed you suggest will cause damage unless you're conditioned, fit and motivated.
I'll bite - how many hours/week do you run?