Inclusion Criteria:  Men and women aged between 18 and 70 years. Prediabetic subjects: glycosylated hemoglobin (HbA1c) between 5.7% and 6.4%. Body Mass Index (BMI) between 25 and 39.9 kg / m2. No weight changes (± 3 kg) during the last 3 months. The subjects must be in general physical and psychological conditions in accordance with the objective of the study. Subjects must be able to understand and sign the informed consent.  Exclusion Criteria:  To be in continuous pharmacological / hormonal treatment, especially those that could affect blood glucose concentration. Suffering from a chronic metabolic disease, or from a systemic intestinal, liver or kidney disease: type 1 or 2 diabetes, severe dyslipidemia, uncontrolled thyroid function disorders, cirrhosis, inflammatory bowel disease, etc. Subjects suffering from severe hyperlipidemia, severe hypertension or hypothyroidism without treatment or treated for less than 3 months. Presence of relevant functional or structural abnormalities of the digestive system, such as malformations, angiodysplasia, active peptic ulcers, chronic inflammatory diseases or malabsorption. Subjects who have undergone gastrointestinal surgery with permanent sequelae (for example, gastroduodenostomy). Chronic treatment with stomach protectors. Subjects suffering from some type of cancer or being in treatment for it or with a period less than 5 years since its eradication. Presence of some type of mental impairment such as depressive pathology, anxiety or untreated bipolar disorder. They will be able to participate if they have stable treatment for at least 3 months prior to the begining of the trial. Allergy or intolerance to any food or food group that is likely to manifest during the study. Be on a special diet (Atkins, vegetarian, etc.) during the 3 months prior to the start of the study. Weight variations (± 3 kg) during the last 3 months. Suffering from eating disorders or eating restrictive behaviors (score on the EAT-26 questionnaire equal or greater than 20). Subjects who have undergone surgical treatment for obesity. Being pregnant or breastfeeding. Abuse of alcohol (more than 14 units in women and 20 units in men) and / or drugs. Show poor collaboration or, in the opinion of the investigator, have difficulties in following the study procedures. Take some type of nutritional supplementation that can affect blood glucose and / or microbiota. If they take it, in order to be included in the study, they will have to stop the supplement, with a washout period of at least 14 days before starting the study. People who are positive for Covid-19 will not be able to participate in the study.