Diabetes is a chronic metabolic disease, which has affected approximately 10.5% of the global population [1]. The most frequent types of diabetes are type-1 and type-2. The third frequent type is gestational diabetes. The pathogenicity of diabetes is multifactorial and involves various factors such as genetic, food, stress, environmental pollutants, and others, in most of the cases combination of two or more factors are noticed. Comparative studies of the influence of palm oil on the activity of xanthine oxidase (XOD) and free radicals in liver and blood. The research compared the effect of palm oil on carbohydrate metabolism in male rats: in young rats and adult rats. The research compared the effect of palm oil on free radicals in male rats: in adults and juvenile rats. Experimental animal body weight change research, 30 days after palm oil treatment. For this scientific research we utilized experimental animals of the male genus: mice of the Wistar type, small mice (45-60 g) and large mice (160-180 g). Experimental animals were divided into groups of six-eight experimental mice and details are shown in the corresponding part of the results. The results are shown in six figures and two tables. Results indicate an increase in the formation of free radicals in blood plasma, both in experimental juvenile mice and in experimental large mice under the influence of palm oil. Palm oil increases the activity of XOD in blood, both in small animals and in large experimental animals. Palm oil increases the formation of XOD in the black liver in both elderly groups. In all groups during the experiment there was an increase in body weight. Results from studies of the effect of palm oil on carbohydrate metabolism showed changes in glucose tolerance test. Current studies for the first time convincingly demonstrate the risk of using palm oil. Analysis of the results of two studies on XOD and carbohydrate metabolism showed a correlation between increased XOD levels and the development of prediabetes.