Calories in vs calories out is a 50 year old, failed theory pushed by the diet industry and public health services. It requires turning a blind eye to how the obesity epidemic continues to spiral out of control.
Public health patronises and plays it's favourite game, blame the patient, whilst sluggishly lagging behind the cutting edge of research into obesity. The diet industry is not interested in truth or weight loss success, they want repeat customers to hawk their obsolete, low fat, high sugar, processed junk to.
There has been a futile misapplication of the First Law of Thermodynamics, that states that energy cannot be created or destroyed, therefore energy consumed must be stored (as fat) or expended (as calories burned).
There is a flaw when this law is applied to the human body, because the body is an open system that adapts to restrictions by changing its metabolic rate. Remember how cold you feel on a diet, that's the body reducing heat loss, therefore calories burned.
The body is not a simple, static, closed system. It is complex, dynamic and adapted for food scarcity, not abundance. Long term food restriction is life threatening to the brain and body on a primal level. Therefore the system chronically fights losing weight with all the hormonal counter measures it can muster.
We experientially know that a simple calorie deficit will not result in long term weight loss, hence the 95% failure rate of diets and exercise programmes. The profound failure of expensive, government backed 'eat less, move more' campaigns has been comprehensively proven beyond all doubt by the data for the last 50 years.
Coincidentally half a century ago, the West's food industry began it's transformation into the new Big Tobacco. Prioritising maximising profit over public health, hooking customers on highly addictive poison, denying the health consequences of consuming it's products, burying research that reflects badly on its practices and aggressively going after any critics and those that filed a lawsuit over it's lies and cover ups.
All evidence points to the unscrupulous food industry being the cause of western society's weight gain with all the hormonal dysregulation and illness that followed. There is no obesity epidemic in Japan, are they somehow biologically different and less feckless or is it that they have protected their food from being contaminated by 'food scientists'?
Big Food wants us to believe that a concurrent rise in obesity rates over that period is simply a personal moral failing of the stupid, modern, Western consumer. They want us to look away from the fact that this contemporary, unprecedented, deadly disease of obesity has it's origins in their ghastly, corrupt industry.