That's debateable, but it is true that 90%+ of weight loss is by diet than exercise for the average joe.
Thing with running is that its too easy to get into a routine. Ask most runners what their daily run is and they'll tell you, then ask them what their run was 6 months ago and they'll give the same answer 9 times outta ten.
The body only changes through adaptation to new stresses, unless it's presented with challenge it wont change. Hasnt it ever bothered you that fat(relativley) people run the london marathon? No way could I do that, yet people with many times my bodyfat can!? odd. The fact is that running is a weight loss fail on a number of fronts -
1) The body is able to quickly adapt to becoming an efficient runner, using fewer and fewer calories for a given distance over time
2)It is 'convenient' both mentally and practically for a runner to maintain the same time and distance over many months and years without progress.
3)A runner builds little muscle in any real sense, the body maintains the bare minimum state required to complete the usual circuit, this means less calories burned the rest of the time, muscle is the calorie furnace without muscle you use very few calories all the time your not in the gym
All of these fact illustrate, pretty irreffutably, that running is a poor fat burner. And all of them can be looked at from the weight training perspective to be positive
1) The body cannot quickly adapt to the stresses that are being put on it in each session due to the high intensity and dynamic nature of a proper training reigieme
2) It is NOT convenient mentally to maintain the same lifts for many months, the user will likely push for even small increases in numbers.
3) Weight training builds significant muscle, enhanced aesthetics aside, this allows more calories to be burnt persuing mundane daily activities and sleeping, burning more calories overall equals faster and easier weight loss.
Sure you can come back and tell me how a runner with proper coaching and or discipline can be always increasing his times and or distances to maintain the dynamic exercise system im criticizing in 1 and 2. But i ask you this, out of all the casual, non competetive runners out there what percent do you think watch their times and alter their routes to consistently improve?
Then ask yourself the same thing about gym goers... Sure there are plenty of hopeless cases on either side but pluck a general percentage out of the air for those two categories and i think you'd be hard pushed not to agree.