RESUMO
OBJECTIVE: This systematic review looked at different clinical trials that explored the beneficial effect of a ketogenic diet on insulin sensitivity in Type 2 Diabetics, both with and without exercise. It was hypothesized that a ketogenic diet is effective in improving insulin sensitivity in individuals with Type 2 Diabetes, with the greatest effect resulting from a ketogenic diet paired with exercise. METHODS: The databases used when searching were the Directory of Open Access Journals and PubMed for randomized control trials, non-randomized control trials, and prospective longitudinal studies. Results were summarized in an evidence table found in the Appendix. Studies were not limited by study type, age of study participants, gender, ethnicity, language, journal in which the studies were published, or geographic location. One study utilized mouse models. Statistical analysis was not performed. RESULTS: Twelve trials were studied. Three trials studied the role of exercise and a ketogenic diet in the treatment of Type 2 Diabetes. Five trials studied a ketogenic diet compared to another diet in the treatment of Type 2 Diabetes. Two trials studied a ketogenic diet alone in the treatment of Type 2 Diabetes. One trial studied a ketogenic diet in those with pre-diabetes. One trial studied a ketogenic diet in those with pre-diabetes and those diagnosed with Type 2 Diabetes. Every trial utilizing a ketogenic diet showed marked improvement in glycemic control among participants in support of the hypothesis. One study noted that while a ketogenic diet greatly improved glycemic control, it created problems with lipid metabolism and the liver. When pairing a ketogenic diet with exercise, hepatic steatosis was avoided. Eleven studies used adult participants, one used mouse models. One study was a prospective longitudinal study, nine randomized control trials, one nonrandomized control trial, and one observational cohort study. CONCLUSIONS: The studies provide encouraging results. A ketogenic diet consistently demonstrates improved glycemic control in Type 2 Diabetics, and in those at risk of Type 2 Diabetes. However, the studies are limited in their lack of exploration of the effects of a long-term ketogenic diet on the liver, with only one study including this data. Randomized trials looking at the effect of a ketogenic diet on the liver are needed. In addition, there were very few studies found when researching that paired a ketogenic diet with exercise to study both the effect on glycemic control, as well as avoiding potential hepatic steatosis.