PURPOSE OF REVIEW: Diet-induced ketosis has a fasting-like effect and brings the body to increase the production of ketone bodies (KB). Works over the last decades have provided evidence of the therapeutic potential of the ketogenic diet (KD). This review focus on mainly clinical research on the effectiveness of the KD and medium-chain triglycerides (MCT) supplementation in ameliorating the severity of symptoms in Alzheimer disease (AD). RECENT FINDINGS: A limited number of clinical studies (short-time and with a small number of participants) evaluated the role of the KD and MCT supplementation in AD as a potential dietary intervention in the therapy of this disease. These studies report that the application of KD or/and MCT supplements to older people reduces symptoms of AD. MCT supplements allow achieving an increased level of KBs in the blood even with a greater supply of carbohydrates in the diet and without any drastic changes in the habitual diet of patients. SUMMARY: The recent literature highlights the potential benefit of using diet-induced ketosis as an additional element of therapy in AD. Since persons with AD are at risk of malnutrition, the use of KD raises certain concerns due to side effects, especially for long periods of time. MCT supplements to obtain similar clinical results without the need for drastic changes in the diet of patients.