To burn one pound of fat in a week, you need to create a 3,500-calorie deficit through diet or exercise, Corey Phelps, an NASM-certified personal trainer, told POPSUGAR. She recommends running three to four times a week for a minimum of 30 minutes to start losing weight, but the number of calories you'll burn varies based on a number of factors, including your weight and pace.
For example, a 145-pound woman running at 5 miles per hour — that's a 12-minute mile pace — would burn roughly 265 calories in 30 minutes. You can estimate your own calorie burn using this online calculator, and then work to make up the difference by cutting calories from your diet.
For best results, Corey suggests varying your speed, as well as the incline or terrain, depending on whether you're running outside or on a treadmill. (If you're a beginner, just be careful not to overdo it — take your time building up your distance and the length, frequency, and intensity of your workouts to avoid injury.) But ultimately, it's your diet that will determine your success. "You cannot outrun poor eating habits," Corey said. "Pairing a healthy diet with cardio and strength-based training is the ideal formula for building a healthy and lean physique."