Calories aren't all created equal
March 27th 2018, 11:59
You wouldn't ask your doctor about nutrition any more than you'd interrogate a nomadic tribesman of the Sahara about the intricacies of snow. The typical doctor's dietary knowledge is primitive, but then, he's only been taught about it in medical school for an average of 10 or so hours over his five years of training.
Most doctors cling to the extraordinary idea, first proposed in 1878 by the German nutritionist Max Rubner, that 'a calorie is a calorie.' Interestingly, it was resurrected in the 1950s by the sugar industry when their products came under public scrutiny for a brief while (before it was successfully deflected to saturated fats in animal products, which became the artery-clogging bad guy until, well, pretty much today).
The 'calorie is a calorie' camp believes it's all to do with quantity, and not quality: all calories are equal. Follow that path to its logical conclusion, and you'll pass through a black hole in deepest space and out into a strange parallel universe where Wonderland suddenly makes sense. In this distorted world, there's no direct-line correlation between what we eat and our overall health—just as long as we're eating enough of anything. Someone who eats 500 calories of Cocoa Krispies every day, for instance, will be as healthy as someone else who munches through a similar quantity of broccoli.
While the 'calorie is a calorie' mantra is the dominant idea in medicine, nations will continue to throw enormous sums at treating the sick (at the most recent count, that's over $3 trillion in the US every year). According to the prevailing wisdom, the sums keep rising every year primarily because people are living longer. But that's simplistic: the real problem is that people are living badly.
That's borne out by a recent survey of grocery shopping habits in 19 European nations. Researchers at the University of Sao Paulo in Brazil estimated how much the average household in each country spent on 'ultra-processed' foods—industrially made products like salty snacks, sugary cereals, instant meals and soda. They found that for every four percent increase in the availability of ultra-processed food, there was a one percent increase in the prevalence of obesity.1
Britain's shopping cart was the least healthy, with ultra-processed foods making up over 50 percent of daily grocery purchases; Germany had the dubious distinction of coming in second, at 46 percent, while these foods made up the smallest part of the diet in Portugal (10 percent) and Italy (13 percent).
Unlike doctors, researcher Carlos Monteiro said he had "deep concerns" about the impact that processed food has on our health and obesity. "Take breakfast cereals like Froot Loops. They are 50 percent sugar, but there is no fruit. Ultra-processed foods are essentially new creations of the food industry with very low-cost ingredients in a very attractive product," he said. Not only are they attractively presented, they are also highly addictive, of course.
The quality-not-quantity school of thought (and one that is diametrically opposed to the 'a calorie-is-a-calorie' theory) has been explored by Valter Longo, a professor at the University of Southern California. He believes we can live to 110 years old, and that's something that is within our grasp today—if we eat healthily. Not only is the quality of the food we eat vital, we should be eating less, and go on a day-long fast at least four times a year when we consume fewer than 800 calories (that's one in the eye for the calorie-is-a-calorie camp).
Eating well (and less) can also reverse a range of chronic conditions, says Longo, including multiple sclerosis and even some cancers—and he's carried out 15 clinical trials to prove it.
And he practices what he preaches, by restricting his sugar intake, eating low to moderate amounts of starches from pasta, bread and rice, and plenty of carbohydrates from legumes and vegetables; protein comes from nuts and salmon rather than from other animal fats.
It's not difficult to follow. "I love food. I'm never hungry, my friends can't believe how much I eat—but people don't understand food. I eat much more food than others, but much less calories," he told The Times.2
But then, he knows that it's about quality, not quantity.
Public Health Nutr, 2018; 21: 18-26
The Times, January 27, 2018