Why cutting sugar won't solve obesity puzzle

Is there is a single answer to this complex and multifactorial problem? Is obesity really caused by sugar or screen time or genes or fat? Photo / Getty

Obesity is on the increase. And so are the numbers of theories all blaming different offenders. Culprit of the month is sugar, with researchers arguing that high levels of sugar in fizzy drinks, sweets and processed foods not only cause aggression and behavioural problems in children but also diabetes, obesity and hidden fat - even in those who look thin.

Sugar is a drug, we are told, and like any drug can create an addiction that causes tolerance and withdrawal leaving us wanting to consume more. Sugar is the "big kahuna" of the lies promulgated by the food industry, the evil factor responsible for society's biggest problem and counter moves include policies such as limiting its intake through banning supersized fizzy drinks as proposed in New York and bans on unhealthy vending machines in schools.

But is the "war on sugar" really the magic solution we have all been waiting for?

Before sugar, we had the evils of carbohydrates as exemplified by the Atkins diet, which encouraged us to eat high protein diets. Carbohydrates, we were told, were just disguised sugars and if we could only be without we would all be thin.

Then there was research showing us that television and computer games were the key causes of obesity, particularly in children. Screen time is dangerous and should be limited to two hours a day to prevent children from becoming fat.

And we have also had the biological theories: the "hunger hormone" grehlin was hailed as a great breakthrough for several years and there has been the never ending search for the obesity gene. Researchers have found genes in rats which make them obese and leptin levels in children linked to weight gain.

And let's not forget the oldest culprit so far in this attempt to solve the obesity puzzle: fat. For many decades now, a low-fat diet has been prescribed as the key to weight maintenance and weight loss which has been the basis for the now iconic "healthy plate", which illustrates what we should eat and in what proportions, and is core to the regimes of most commercial weight loss programmes.

Nothing new to this holy grail

Even in the 1800s there were many solutions to obesity including Dr Schindler Barnay's Marienbad Reducing (Anti-Fat) Pills and Lord Byron's choice diet of potatoes flattened and drenched in vinegar.

I definitely don't want chips with my vinegar. Back then the search was also on for the "single" explanation that could fix the population's waistlines and with each solution presented as the "real" answer that superseded all others.

But is there is a single answer to this complex and multifactorial problem? Is obesity really caused by sugar or screen time or genes or fat? Or is the answer simply: all of the above?

We can't just be addicted to sugar as no one gets the sugar out of the cupboard to eat on it's own. We don't say we're addicted to fat when it comes in the form of chips and curry. And genes alone can't explain it as people gain weight when they move countries even when their genes stay the same.

Many researchers want to find a single solution to this problem as this brings acclaim, glory, citations and the understandable satisfaction of having solved a problem. And researchers also tend to belong to specific disciplines, whether it's nutrition, genetics, psychology or biochemistry, and need to believe that their discipline has the true explanation. And "all of the above" isn't going to do anything for anyone.

But maybe "all of the above" is as good as it's going to get - and actually the way we should be going. Obesity is simple: overeating and under-activity, probably helped by a dose of obesity-prone genes. But a simple explanation is not a single explanation, and while trying pin down a single culprit may help academic careers, it does nothing for solving this recalcitrant problem.

• Jane Ogden, Professor of Health Psychology, University of Surrey

•This article was originally published on The Conversation. Read the original article.