Metabolic syndrome affects persons of all ages and has been associated with cognitive decline. In a sample of 221 healthy adults (18.57 to 85.33 years), assessed up to 3 times (over up to 6.33 years), we applied a second-order bivariate dual-change-score model with strong factorial invariance to estimate the effects of previous levels of metabolic risk (MR) and fluid intelligence (Gf) on subsequent changes in both constructs. The results indicated that MR levels affect subsequent changes in Gf, whereas Gf does not affect changes in MR. This suggests that control of MR may be related to the change in a person's cognitive status, making early intervention, starting in young adulthood, a promising approach. To our knowledge, this is the first long-term study with such evidence.