The purpose of this literature review was to describe if the nutritional balance of the fats, carbohydrates, proteins and fibers can lead to weight reduction and to improve glucos-/blood lipid for individuals with obesity and type 2 diabetes. The method used was a literature review. Twenty-two scientific articles were chosen, which were consistent with the study purpose and questions. The articles were selected based on searches in the Medline database by PubMed. The keywords used were type 2 diabetes mellitus, diet, obesity, comparative, fat, carbohydrate, low carbohydrate, high fat and saturated fat. The articles were reviewed critically to assess their quality. In most of the studies, it turned out that the cost recommendations all resulted in different results of reduced weight, BMI and waistlines irrespective of which diet you choose. Some studies showed changes in blood sugar / blood lipid values, primarily that high intake of fat increased blood fat values. The conclusion of this study is that changes in dietary habits can result in increased weight loss and improved blood sugar / blood lipid values.