AS a ‘specialist in generalisation’ I feel most comfortable falling back on those aspects of Lifestyle Medicine in which there is the least controversy.
Exercise, for example, is pretty much settled: we need more of it, we suffer from less of it. Sure, there are some internecine squabbles about the best type of exercise for the most benefits — resistance training for muscle maintenance; aerobics for the heart — but generally the scientific view is that a little exercise is better than none, and more is better than a little.
Now consider nutrition: Do we really know whether a low-carb diet is better than a low-fat diet for everyone? Or if the Mediterranean diet is better than the Scandinavian diet? Or if high-protein meals are better for weight loss than low protein?
Many people think they do, hence the waves of armchair experts and celebrities which arise from time to time, each pushing a barrow with a revolutionary new diet, based usually on a life-changing experience.
For anyone with experience in the area, these revolutionary dietary approaches are reminiscent of the Bill Bryson book, A Short History of Nearly Everything. Bryson writes in one chapter about a period in the 1980s when a crater discovered in the wilds of Iowa was thought to be the site of the comet crash that wiped out the dinosaurs.
Scientists descended in droves, and two little-known earth scientists, Ray Anderson and Brian Wilke, had their five minutes of fame — until someone found a more probable dinosaur death crater on the Yucatan peninsula. Anderson and Wilke’s short-lived and improbable fame was clouded by the dust of departing scientists who couldn’t get out of Iowa fast enough.
Similar things happen in nutrition. While our understanding is progressing, there are underlying cycles of popularity for various theories.
The sugar-is-solely-responsible-for-the-modern-obesity-epidemic movement is a case in point. It was spurred by the apparent failure of a decline in fat consumption to reduce obesity around the turn of the millennium. In fact, this was based on a false premise, as fat consumption did not decrease, it’s just that everything else (total energy) increased. And therein lies the rub.
World-renowned obesity researcher Professor Boyd Swinburn, from Auckland University, has demonstrated that the increase in food consumption (total energy) in the US over the past 50 years is enough on its own to explain the obesity epidemic [1]. No need to invoke sugar or fat or anything else!
Certainly, no nutrition scientist worth his or her salt would advocate an increase in sugar (whether, fructose, glucose or sucrose) for good health. But to invoke its consumption as responsible for everything from stomach aprons to jock itch is a bridge too far.
Indeed, when sugars are substituted isocalorically for other carbohydrates, or even fats, there is nothing unique in regard to sugar consumption and obesity.
We are likely to find in coming years that there are negative individual responses to sugars, as there are to other nutrients in foods.
In the meantime, there is abundant evidence to suggest that it is the consumption of all energy-dense nutrients (food volume), including added sugars, underpinning the modern obesity epidemic.
It’s a matter of time before the sugar equivalents of Iowa’s Anderson and Wilke are left in the syrupy haze of deserting experts, off to worship yet another crater. One wonders where the next nutritional Yucatan peninsula will be.
Reference
1. Lancet, 2015; 386 (10005):1716–17
This article originally appeared in Medical Observer.
