Can you define their failures as they burnt more than they eat and still gain weight? Did they checked strictly with the math? Are you 100% sure when they fail, they were eating less calorie in total than the amount they are burning!?

If a person is eating 1000 calories per day regardless what what food, and is burning 2000 calories per day (CO), how is anyone going to gain weight this way?

Please, as I mentioned above, there are many variables, but not the core principle of CICO which is basic math. You cannot create calories out of thin air! It doesn't mean anyone can stick to strict diet with CICO calculation. It doesn't mean they always measure accurately. Don't mix up the failure in application with the principle. I watched many cooking videos in youtube. It doesn't mean that im gonna cook well; It doesn't mean that the recipe is bad