Conventional wisdom holds that your chance of becoming obese depends mainly two obvious factors: your diet and how much exercise you get.
But recently, some scientists have been testing the notion that an entirely unrelated factor can play a role.
That's the conclusion of a new study by Air Force public health researcher Jameson Voss and others, published in the journal PLOS ONE. Rather than pointing to diet or exercise-related factors that have to do with high altitude (like, say, going hiking in the mountains), they point to the impact that low levels of oxygen can have on the body.
Previous work has found that at higher altitudes — when less oxygen is present in the air — the human body produces higher levels of leptin, a hormone that reduces hunger.
Experiments have also shown that production of the hormones cholecystokinin (which also suppresses appetite) and norepinephrine (which reduces blood flow to the stomach, indirectly reducing hunger) also go up at high altitudes.
There's also the possibility that your body has to do more overall work just to sustain its normal activities with less oxygen present, causing it to burn more fat over time.
In the most recent study, a team of American researchers sought to investigate whether long-term residence at high altitude actually confers benefits in humans when it comes to losing weight. The study analyzed about 100,000 U.S. Army and Air Force servicemen and women, all with at least two years of service, from January 2006 to December 2012. During that time period, they moved between assignments at high altitude (1.2 miles above sea level or higher) and low altitude (0.6 miles or lower). All the participants had an overweight but not obese body mass index (BMI) equal to or less than 25, but no greater than 30.
“These results suggest that moving to high altitude would protect an
overweight person from moving to obesity,” said, Dr. Jameson D. Voss,
lead author of the study and a consultant with the United States Air
Force School of Aerospace Medicine. The researchers speculate leptin and other hormones that are involved in
appetite control rise at high altitudes, which may help explain the
finding.
Naturally, there's still a lot more study to be done, but it does give researchers some...well, you know. Food for thought.
What do you think of this research? And do you live in a high altitude or a lower one?
