Doctor gains 7kg in a month after eating 80% ultra-processed food

A 42-year-old doctor and TV presenter, Chris van Tulleken, carried out an unusual experiment. For four weeks, he ate a diet made up of 80% ultra-processed fast food. Before starting, he weighed nearly 82 kilograms. During the experiment, van Tulleken’s family also began eating the junk food stored at home. By the end of the month, he had gained seven kilograms, reaching 87.7 kilograms. His health suffered as he experienced sluggishness, poor sleep, heartburn, constipation, and hemorrhoids.

The diet also affected his brain. He developed a food addiction, with new neural connections forming. Even after stopping the experiment in October last year, he continued to crave fast food. These changes persisted despite his return to a healthy diet. The experiment led to a significant weight gain of 7 kilograms in just one month. It also caused lasting cravings and measurable brain changes. Van Tulleken eventually switched back to a healthier way of eating after the study concluded.