Actually, it should be “running, but not losing any weight,” because I don’t lose any weight by running. If you’re not already a runner, but take up running, you might lose several pounds initially as your body adjusts to doing something it hasn’t been used to doing. But if you’re serious about losing weight, running is not a means to that end. My weight doesn’t ever change with running. Those times when I have lost some weight, I’ve done it by controlling what I eat. But if you’re going to run, you’re also going to have to eat. There’s no such thing as dieting and running. You eat and you run. Given my size, I’ll burn roughly 150 calories per mile. If you do the math, that’s about 450 calories for a 5K, or almost 1/4 of a daily 2,000 calorie intake. Running a 10K will require close to a thousand calories. Running a half-marathon requires nearly 2,000 calories — an entire day’s worth of eating. All that energy has to come from somewhere. Those calories have to be replenished if you are going to run regularly. In fact, running 15-17 miles a week requires me to increase my caloric intake by roughly 15-20% above what I’d eat if I didn’t run. This is why running doesn’t translate into weight loss. The two are incompatible.