CICO stands for calories in vs calories out by the way.
I often read the weight loss section on here. Every day there are people embarking on any number of diets and body overhauls and I reckon about 95% of them are unsuccessful. Calorie counting, shake diets, you name it, people always gain the weight back before long. Even celebrities who seem to have done well with weight loss eventually gain it back, e.g. Pauline Quirke. I am watching that new amazon show with Melissa McCarthy and she is also back to being around the same size she was before starting her weight loss. Lisa Riley is another one who lost a lot of weight and most of it is back now. Clearly it's not working and people are making money out of telling fat people that they can be thin if only they want it bad enough or try hard enough. The scientific research shows that once you are morbidly obese, you have an absolutely miniscule chance of getting to and maintaining a normal BMI without surgery. Yes, there will no doubt be people popping up here saying they did just that but you are the exception.
The idea that if you just eat less than you burn is also flawed when a) your body adapts to lower amounts. For instance, those who have gastric bypass and eat v low calories forever still tend to be overweight/mildly obese because their bodies just can't get to a low BMI and b) you're fighting against intense hunger urges that someone who has always been normal weight just can't imagine dealing with.
If I was morbidly obese, I would ditch all the dieting crap, admit that I couldn't fix it and have surgery. I see so many dieting plans just blame the dieter for 'failure' when they're trying to do something impossible. If I was stage 1 obese or overweight, I'd go low carb no-processed for life because I think that is the only thing that switches off the hunger signals in the brain.