How Sugar, Ultraprocessed Foods Are Shaping the Health of America's Youth

In a recent interview, Robert Lustig, MD, MSL, endocrinologist and professor emeritus of pediatrics at the University of California, San Francisco, shed light on the troubling impact of sugar and processed foods on children’s health. Lustig highlighted how the prevalence of sugar in baby food and unhealthy school meals are driving long-term health risks for younger generations.

Lustig expressed concern over how the food industry deliberately adds sugar to baby food to encourage brand loyalty early in life. “This is a very specific plot within the ultraprocessed food community to hook kids on sugar as early as possible,” he explained. Lustig noted that research from multiple countries, including the United States, has shown that babies today weigh, on average, 200 grams—almost half a pound—more at birth than they did 25 years ago.

“And when you stick them in a scanner, you find out that 200 grams is all fat,” he added. “We have an epidemic of obese newborns.”

This excess weight in newborns, Lustig said, points to more than just diet and exercise—it begins in the womb. He emphasized that addressing children’s sugar consumption starts with the parents. “How about cutting back on the mother’s sugar intake so that the kid never got it in utero?” Lustig suggested, arguing that tackling sugar intake throughout society is crucial.

Adolescents also face unique health challenges. Lustig explained that insulin resistance—a state in which the body struggles to use insulin effectively—is a natural part of puberty, driven by growth and sex hormones. However, when combined with the availability of sugary, processed foods, this biological phase can lead to unhealthy eating habits.

“When your insulin level is high, you want that cookie—you don’t need that cookie, but you want that cookie,” he said, highlighting how excess insulin blocks the hormone leptin, which normally signals fullness and satisfaction.

Lustig also criticized the role of the National School Lunch Program in perpetuating unhealthy eating patterns, despite claiming it provides “nutritionally balanced” meals. “What children are being served in school today is ultraprocessed food,” he said. “It’s not even food because it doesn't actually meet the criteria for the definition of food.… Ultraprocessed food inhibits growth and inhibits burning.” He argued that a shift toward serving “real food”—defined as food grown from the earth or animals fed naturally—could help reverse these trends.

As the chief science officer of Eat Real, a nonprofit focused on bringing nutritious food to K-12 schools, Lustig has spent the last 6 years expanding the program across 600 schools and counting in the US. The organization aims to make real food a national standard in schools, helping students develop healthier eating habits early in life.

Lustig’s message is clear: Real food, not processed alternatives, is essential for promoting health and curbing obesity in children. Addressing sugar consumption and improving school meals, he believes, are key steps to ensuring a healthier future for the next generation.