Overweight adults were randomly assigned to eat ultra-processed or unprocessed meals (defined according to the so-called NOVA classification) for two weeks. Meals had the same calories, macros, sugar, salt, and fiber and energy density, but everyone was allowed to eat as much as they wanted. The best part is that all participants were monitored 24/7 in a so-called “metabolic chamber”, meaning that EVERYTHING they ate was controlled. Unlike most other studies where people report food diaries (and lie), this makes this study much more valid.
People on the ultra-processed diet ate 500 more calories per day (from carbs and fat, not protein!). They ended up gaining 0.8 kg (1.8 lb)! Meanwhile, people eating UN-processed food LOST 1.1 kg (2.4 lb)! Interestingly, both groups found the diets equally pleasant. Eating healthy doesn’t have to mean you suffer! You CAN have that pizza and get the body of your dreams.