A study published in the journal Frontiers in Nutritionanalyzed more than 100 peer-reviewed papers on the keto diet and concluded that “the ketogenic diet is especially unsafe for pregnant women and people with kidney disease and may increase chronic disease risk for the general population.” The study linked the diet to elevated levels of low-density lipoprotein (LDL) cholesterol—commonly known as “bad” cholesterol—and an increased risk of cardiovascular disease, cancer, diabetes, and Alzheimer’s disease.