Advanced glycation end products (AGEs) are a heterogenous group of compounds form mainly by the Maillard reaction. AGEs can be found endogenously and in some foods. Several AGEs have been characterized, but carboxymethyl-lysine (CML) is one of the most widely studied in foods. Several studies have demonstrated the association between advanced glycation end products and several pathologies. However, few studies have focused on studying the absorption and excretion processes of these glycation products. Therefore, the objective of the study is to evaluate the effect of carboxymethyl-lysine (CML) on the levels of absorption and excretion of CML, and in the microbiota of healthy adults. To achieve the objective, a randomized clinical trial will be carried out, which will consist of a 7-day washout period during which participants will receive general recommendations that allow them to stick to a diet with a low CML content, adherence to these recommendations will be evaluated through three dietary records. At the end of the washing period, participants will be randomly assigned to either a high-CML or to a low-CML diet for 5 days. Participants will receive the 5 corresponding meals (breakfast, lunch, snacks and dinner) during the 5 days of the intervention, these preparations will be elaborated by a catering company with indications and supervision by the research group. Participants will assist to the research center to receive the breakfast, lunch and snacks. After lunch the subjects will receive a package containing a snack for mid-evening and the dinner. Adherence to the diet during the intervention period will be evaluated through a dietary record of foods.