Cynically, I’ve been known to ask for examples of population based initiatives that actually led to sustained increases in physical activity (with the expectation of there not being any).
Well, I can’t do so anymore as Scotland’s managed to increase recreational walking by 13% over a 6 year period for the whole of their population!
Their National Walking Strategy targeted Scotland’s 5 million residents with messages about the health benefits of walking.
The strategy involved multiple sectors including:
And together their aim was to create a culture of walking by way of developing better walking environments that supported ease and convenience.
How to counsel patients on physical activity became a topic in medical schools. The Daily Mile encouraged 1,000 schools to help every student walk, run, or jog a mile a day, increased funding for active transport programs was obtained including a doubling of infrastructure funding for same, #SoMe was leveraged to share encouragement and information to the public, and community walking programs were launched nationwide.
Now before you get too excited, the bar was low to begin with whereby the increase in walking represented the self-report of walking at least 30 minutes for recreation once over the past month, but at least it’s a start.
Changing behaviour requires more than just education and a good reason to do so, it also requires a change to social norms and culture, as well as environmental engineering. Clearly there’s more to do in Scotland and elsewhere, but nice to see that these needles might actually be movable.
One of the possible reasons that in freely living humans exercise doesn’t seem to add up to weight loss as math might predict is that freely living humans might eat back their burned calories. Some may do so consequent to increased hunger. Others to a sense of virtue and the inclination to reward themselves for their hard work. Others still because marketing has convinced them that they must refuel, recover, replenish, etc..
A new study,Activity energy expenditure is an independent predictor of energy intake in humans, published this year in the International Journal of Obesity, set out to look at this phenomenon.
Now to be clear, the study certainly wasn’t designed to explain exercise’s impact on weight. It was just 7 days long and it involved the retrospective analysis of data from 5 prior studies and did not directly measure energy expenditure or energy intake. Instead researchers utilized estimated energy expenditure by way of heart rate and indirect calorimetry data, and energy intake by way of known to be problematic food diaries.
My stats skills are nowhere near good enough to comment on the various treatments of the data, but here’s the scatter plot of the impact of energy expenditure on energy intake.
The increase in energy intake the authors attributed to energy expenditure wasn’t high, roughly 3% of total daily calories (around 70 in this sample), an amount too small to explain away exercise’s often uninspiring impact on weight loss.
Truth be told, I’d have predicted the difference to be larger as eating more consequent to exercise is something I know many people do for one or more of the various reasons mentioned above.
Of course none of this changes the fact that exercise has tremendous health benefits at any weight and that weight shouldn’t be your driver for upping yours if you’re able.