Researchers reveal the complex link between ultra-processed foods and obesity
More than 40 percent of Americans are obese, and this epidemic is closely intertwined with a host of comorbidities such as Type 2 diabetes
[Jan. 17, 2024: JD Shavit, The Brighter Side of News]
MIT engineers designed an ingestible capsule that vibrates within the stomach, creating an illusory sense of fullness and reducing appetite. The pill could offer a minimally invasive, cost-effective way to treat obesity. (CREDIT: MIT News)
America is facing a staggering health crisis. According to the Centers for Disease Control, more than 40 percent of Americans are obese, and this epidemic is closely intertwined with a host of comorbidities such as Type 2 diabetes, heart disease, and cancer.
But what is the root cause of this growing health concern? Recent discussions hosted by Harvard's T.H. Chan School of Public Health shed light on a troubling culprit: ultra-processed foods.
These conversations brought together experts from Harvard and the National Institutes of Health (NIH), as well as journalist Larissa Zimberoff, author of "Technically Food: Inside Silicon Valley’s Mission to Change What We Eat." They aimed to dig into the mechanisms by which ultra-processed foods, commonly found in the middle aisles of grocery stores, might be driving the obesity crisis in the United States.
Kevin Hall, a senior investigator at the National Institute of Diabetes and Digestive and Kidney Diseases at the NIH, kicked off the discussion by highlighting the alarming findings from a study published in 2019. Participants in this study were randomly assigned to follow either ultra-processed or unprocessed diets for two weeks, followed by a switch to the alternate diet for another two weeks.
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"What we found was that people consuming the ultra-processed foods ate about 500 calories per day more over the two weeks that they were on that diet as compared to the minimally processed diet," Hall stated. "They gained weight and gained body fat. And when they were on the minimally processed diet, they spontaneously lost weight and lost body fat."
These results suggest a strong link between diets high in ultra-processed foods and overconsumption of calories, providing a critical piece of the puzzle in understanding the obesity epidemic.
To further contextualize this issue, Hall introduced the NOVA classification system, which categorizes foods into four groups based on their degree of processing. Ultra-processed foods, he explained, fall into one of these categories and are distinguished by their manufacturing techniques, such as extrusion, molding, and preprocessing by frying. Panelist Jerold Mande, CEO of Nourish Science and an adjunct professor of nutrition at the Chan School, added that some ultra-processed foods, like shelf-stable breads, are essentially "very sophisticated emulsified foams."
Ultra-processed foods are one of the four categories of something called the NOVA classification system developed by the School of Public Health at the University of São Paulo, Brazil. (CREDIT: ResearchGate)
However, it's worth noting that not all ultra-processed foods are created equal. Hall and his team are currently conducting a follow-up study aimed at examining different qualities of ultra-processed versus whole foods. They are investigating factors such as energy density, palatability, and portions to gain deeper insights into the varying health impacts of these foods.
"These are only two potential mechanisms, the calories per gram of food — that's the energy density of food — and the proportion of foods that have pairs of nutrients that cross certain thresholds, foods that are high in both sugar and fat, salt and fat, and salt and carbohydrates," Hall explained.
Body weight and composition changes. The ultra-processed diet led to increased body weight over time whereas the unprocessed diet led to progressive weight loss. (CREDIT: National Library of Medicine)
Josiemer Mattei, the Donald and Sue Pritzker Associate Professor of Nutrition at the Chan School, emphasized the importance of reducing consumption of ultra-processed foods across the board. She cited emerging evidence linking higher consumption of these foods to the development of Type 2 diabetes and cardiovascular diseases, especially coronary heart disease.
"All the panelists agreed that obesity and negative health outcomes have risen alongside consumption of ultra-processed foods," Mattei noted.
Jerold Mande concluded the discussion by underscoring the need for increased investment in scientific research, stronger regulatory oversight, and leveraging large-scale programs to address this pressing issue. The consensus among the experts was clear: tackling the obesity epidemic and its associated health problems requires a comprehensive and concerted effort.
As the United States grapples with the alarming rise in obesity rates, understanding the role of ultra-processed foods in this epidemic becomes increasingly crucial. While more research is needed to uncover the full spectrum of health impacts related to these foods, the evidence presented during this panel discussion suggests that they play a significant role in driving overconsumption of calories and subsequent weight gain.
As we strive for better health outcomes, the focus must shift towards reducing our reliance on ultra-processed foods and promoting healthier dietary choices.
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