A massive diet switch has occurred in the occidental world since the second half of the 20 th century, with a dramatic increase in refined carbohydrate consumption generating numerous deleterious health effects. Physiological mechanisms associated with refined carbohydrate consumption, such as hyperinsulinemia and insulin resistance, may impact cognition in healthy people before overt obesity, metabolic disease onset or dementia. To explore this possibility, the relationship between cognitive performance and chronic refined carbohydrate consumption was studied in healthy young adults (N = 95). Evaluation of chronic refined consumption was based on the glycemic load (a proxy of glycemic and insulinemic responses) of three mealtimes at higher glycemic risk: breakfast, afternoon snacking and between-meal snacking. Immediate consumption of refined carbohydrates was experimentally controlled. High chronic between-meal glycemic load is associated to a decrease of cognitive performance for men and women in the presence of several control variables, including energy intake. The different physiological ecologies of the three meals and the interpretation of the results in terms of adaptation or maladaptation to the modern dietary environment are discussed.