The research, published in "Proceedings of the National Academy of Sciences," looks at the impact of caloric intake, energy expenditures and diet on obesity in countries with economic development.
Research co-authored by Assistant Professor of Biology Amanda McGrosky was recently highlighted by HuffPost in an article titled “This Big Myth About Metabolism Won’t Go Away.”
The article challenges the misconception that thin people have a “naturally fast metabolism,” but a recent study co-authored by McGrosky and published in “Proceedings of the National Academy of Sciences” found that metabolic rates remain fairly stable across populations, suggesting other modern factors are at play. Researchers evaluated the daily calorie burn, body fat percentage and BMI of thousands of people across 34 different countries. They found that physical activity may play less of a role than previously believed.
“When we look at different populations with very, very different lifestyles — for example, pastoralists, who are moving with herds of sheep and camels — they have similar body-size adjusted total energy burn as someone who is living in the U.S. sitting at their desk typing on a computer all day,” said McGrosky.
The research aligns with previous studies showing that the body adjusts based on the way people expend energy to keep calorie burn at a stable level.
“We do see that people will increase their calorie burn when they start picking up a new exercise regime, and they might lose some weight initially. But over the long term, they tend to plateau,” McGrosky said.
McGrosky says what people eat plays a greater role than energy expenditure.
“I think it’s really a product of your social environment and the types of foods that are accessible to you,” McGrosky said. “That does correlate with socioeconomic status, but it varies a lot depending on the country and the population … From the policy standpoint, I think it’s really important to ensure that everyone has access to these fresh foods that are not processed, foods that actually occur in nature, because our bodies did not evolve to digest ultraprocessed foods.”