The use of the ketogenic diet is a safe and effective process to reduce the health complications of obesity, thus losing weight while preventing weight regain at the same time. Humans have metabolic flexibility and the potential to utilize ketones as an energy source by reducing carbohydrate intake in the diet, this reduces insulin levels, and ketogenesis occurs. These conditions promote the release of excess stored fat, avoid muscle weakness, and improve insulin sensitivity. Losing weight by diet causes appetite feeling and a rise in ghrelin release, that raises the likelihood of regaining weight and is thus counterproductive to goals for weight reduction. The study's aim is to review evidence on a ketogenic diet for weight loss and metabolic illnesses like insulin resistance, lipid disorders, cardiovascular disease, fatty liver disease development, and Polycystic Ovarian Syndrome and exercise and delay aging, in addition to addressing the side effects of the ketogenic diet, and thus we provide basic information about nutritional ketones and the mechanism of their generation.