We’ve been told that the world is getting fat because we’re all eating too much, but new research says that for America at least this isn’t true: it’s our lack of exercise that is probably to blame.
Publishing this month in The American Journal of Medicine, researchers from Stanford University in California, provide us with a new analysis of the National Health and Nutrition Examination Survey (NHANES), a program of studies that aim to assess the health and nutritional profile of adults and children throughout the United States by combining personal interviews and physical examinations.
In particular, the researchers wanted to see how rising rates of obesity, and what’s known as abdominal obesity, showed up in the data and what their strongest associations were: diet or exercise.
To investigate this the researchers looked at data in the NHANES that tracked diagnosed obesity, abdominal obesity, reported physical activity, and reported caloric intake in adults in the U.S. taken from 1988 to 2010. What they found is that levels of exercise have dramatically decreased, something that appears to be contributing to the rise in obesity.
For instance, the number of women who said they took no physical exercise during the study period went from 19.1 percent in 1994 to 51.7 percent in 2010. The figure for men isn’t much better, going from 11.4 percent to 43.5 percent.
Unsurprisingly, the average Body Mass Index rating (BMI) increased across every age group, but the most dramatic rise was found among young women between 18-39.
The researchers then looked at food intake. While the researchers didn’t dig down into what kinds of food are being consumed, the data actually shows that the overall daily calorie intake and levels of fat, carbohydrate and protein that are being consumed hasn’t changed significantly over the last twenty years.
This is very interesting as we are often led to believe that people in the West are simply consuming more food and that this is the key factor in obesity rates, but it appears that this isn’t true–it’s our sedentary lifestyles that are really driving up our BMIs.
“These changes have occurred in the context of substantial increases in the proportion of adults reporting no leisure-time physical activity, but in the absence of any significant population-level changes in average daily caloric intake,” says Uri Ladabaum, lead researcher and associate professor of medicine at Stanford University’s School of Medicine. ”At the population level, we found a significant association between the level of leisure-time physical activity, but not daily caloric intake, and the increases in both BMI and waist circumference.”
What’s the reason for the drop-off in activity rates? It’s probably not just that we’re getting lazier, but more to do with that we’re working more which leaves little time for exercise. That’s something that future research will have to explore.
Now it’s important to stress that BMI is not always an accurate predictor of health, which is something that the researchers have noted. However, as a guideline this research provides an interesting insight, especially in how it appears that physical activity and a lack thereof is what really might be driving the so-called obesity epidemic.
That said, we know that exercise alone doesn’t yield the kind of weight management results that exercise teamed with a healthy diet can bring. We also have plenty of research that says a diet rich in legumes and other vegetables is important for supporting overall body health and a strong nutritional profile that keeps the body working at its best. This study does not change that, but it does suggest that in the national battle against the bulge we might wish to switch some of our focus from what we’re all eating to how much we’re moving.
If you find it hard to fit in exercise in your very busy schedule, you might consider how to incorporate exercise into your daily routine. There’s the obvious, like taking the stairs instead of the elevator and walking rather than using the car whenever possible. If you’re stuck at the office though, you might also consider taking a look at how circumspect exercises using your office environment can help you stay healthy while on the job. It’s not a replacement for dedicated and regular exercise, but if you’re working late it can be a good temporary fix.
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