This study investigated the association between ultra-processed foods (UPF) and the risk of metabolically unhealthy normal weight (MUNW) and metabolically unhealthy overweight/obese (MUO). We included 512 normal-weight and 787 overweight/obese adults with a metabolically healthy phenotype from the Tehran and Lipid Glucose Study, who were followed from the third (baseline) to the sixth study examinations. Each 10% increase in energy intake from UPF was related to a 54% (95% CI = 21-96%) and 2% (95% CI = 1-3%) higher risk of MUNW and MUO, respectively. The risk of MUNW was significantly higher in quartile 4 compared to quartile 1. The restricted cubic splines suggested that the risk of MUNW increases monotonically when UPF accounts for at least 20% of energy intake. No non-linear association was observed between UPF and the risk of MUO. Energy intake from UPF was positively related to the risk of MUNW and MUO.
Keywords: Metabolically unhealthy normal weight; NOVA; cardio-metabolic; food classification; food processing; metabolically healthy obese; ultra-processed foods.