The difference in global obesity levels could be tied more to the consumption of ultra-processed foods than to a sedentary lifestyle, according to new research. The food we eat "plays a far greater role than reduced energy expenditure in obesity," said a study published in the journal PNAS. After collecting data from 34 countries or cultural groups, researchers found the "total calories burned per day is really similar across these populations", despite differences in lifestyle and activity levels, Herman Pontzer, a senior author of the study, told NPR.
The findings support a theory about human metabolism called the constrained total energy expenditure model, which says that "our brains and bodies closely monitor our total energy expenditure, keeping it within a narrow range," said The Washington Post. Essentially, the body's metabolism adjusts to a person's lifestyle.
This indicates another culprit contributing to obesity, and a subanalysis by the researchers found that people "in countries that got more of their calories from ultra-processed foods tended to have more obesity and higher body fat percentages," said NPR. These foods are "making us fat not just by tempting us to eat more but also by allowing our bodies to absorb more calories from each bite," said News Medical.
Many Americans do not have access to healthy high-quality food. "We have been telling Americans that you are lazy, you are not moving enough, you are eating too much," Dariush Mozaffarian, the director of the Food is Medicine Institute at Tufts University, said to NPR. "And I think what this study shows" is that "our food is driving this." | 
