It is much easier to stay on a low carb diet - the hunger simply goes away, sugar cravings go away and there's no willpower needed to eat less - you do it automatically.
Once again, yes, "calories in /calories out" balance is the gauge whether you lose or gain weight, but not all calories are the same. Some are empty junk, some bring actual nutrition your body needs, learn to separate them. It is easy to lose weight if you choose wisely. But it is really hard or impossible if you follow the whole-grain fat-phobic common wisdom.