https://aeon.co/essays/sugar-is-a-toxic-agent-that-creates-conditions-for-disease

The energy balance paradigm implies that the only way in which foods influence our body fat is through their energy content, or calories – that is, through the energy that we absorb without excreting, and so make available to be oxidised or stored. This is the only variable that matters. It’s the implication of the phrase ‘a calorie is a calorie’, which, by the 1960s, had become a mantra of nutrition and obesity researchers, evoked invariably to support the dogma that only calories count when it comes to understanding and treating human obesity.

This logic has been the lifeblood of the sugar industry. If sugar was uniquely toxic, in that it possessed some special property that made us respond to it by accumulating fat or becoming diabetic, then government health agencies would have to regulate it. If all sugar does is add calories to the diet, just as any other food does, then it is, in effect, benign. When the sugar industry embarked in 1956 on a nationwide advertising offensive to knock down reports that sugar is ‘fattening’, it did so on the seemingly sound scientific basis that ‘[s]ugar is neither a “reducing food” nor a “fattening food”’, as the industry advertisements explained. ‘There are no such things. All foods supply calories and there is no difference between the calories that come from sugar or steak or grapefruit or ice cream.’

Thinking of obesity as an energy-balance disorder is as meaningless as calling poverty a money-balance problem

Even 60 years later, in 2015, when The New York Times reported that academic researchers were doing the bidding of Coca-Cola by taking its money to fund a Global Energy Balance Network and ‘shift blame for obesity away from bad diets’, this was still the logic invoked in sugar’s defence: if you believe that obesity is caused by a mere caloric surplus, then the solution to the epidemic is not necessarily to avoid Coca-Cola, but to either consume it (and everything else) in moderation or to burn off the excess calories with physical activity. For the sugar industry and the purveyors, such as Coca-Cola, of sugar-rich foods and beverages, this remarkably resilient, century-old conception of why some of us get fat (or are born fat) and others don’t (or aren’t) has been the gift that keeps on giving.

So here’s another way to frame what is now the imperative question: is the energy-balance hypothesis of obesity correct? Is it the right paradigm to understand the disorder? The competing hypothesis has existed for over a century: in this paradigm, obesity is not an energy-balance disorder but a disorder of excess fat accumulation and so, clearly, a hormonal and metabolic disorder – the result of an ‘endocrine disturbance’, as it was phrased in the 1930s by Eugene Du Bois, then the leading American authority on metabolism. By this logic, the foods we eat influence fat accumulation not because of their caloric content but because of their macronutrient content, the proteins, fats and carbohydrates they contain. This paradigm attends to how organisms (humans, of course, in particular) orchestrate the careful ‘partitioning’ of the macronutrient fuels they consume, determining whether they will be burned for energy or stored or used to rebuild tissues and organs. It proposes that dysregulation of this exquisitely-evolved, finely-tuned homeostatic system (a system that is biologically balanced) is the necessary component to explain both the excessive storage of calories of fat – obesity – and the diabetes that accompanies it.

This alternate hypothesis implies that sugar has unique effects in the human body leading directly to both diabetes and obesity, independent of the calories consumed. By this way of thinking, refined sugars are indeed toxic, albeit over the course of years or decades. We get fat and diabetic not because we eat too much of them – although that is implied tautologically merely by the terms ‘overconsumption’ and ‘overeating’ – but because they have unique physiological, metabolic and hormonal effects that directly trigger these disorders. If all this is right, then thinking of obesity as an energy-balance disorder is as meaningless as calling poverty a money-balance problem (caused, of course, by earning too little or spending too much, or both). By conceiving of obesity as a problem caused by the behaviours of excessive consumption and physical inactivity, researchers not only took a physiological defect – the excess accumulation of fat, often to a massive extent – and turned it into a behavioural problem. But they made a critical error, one that has grown over the course of decades into an idea that seems too big to fail.

(http://www.autoadmit.com/thread.php?thread_id=3770562&forum_id=2#34495049)