Animal based low carbohydrate diet is associated with increased risk of type 2 diabetes in Tehranian adults

BACKGROUND: To investigate the association of low carbohydrate diet (LCD) score with the risk of type 2 diabetes among adults. METHODS: This cohort study was conducted on 4356 healthy participants aged ≥ 19 years old, who were followed-up for a mean duration of 3 years within the framework of the Tehran Lipid and Glucose Study. LCD score was calculated using a food frequency questionnaire according to intake of carbohydrate, protein, and fat at baseline. Diabetes was defined according to the criteria of the American Diabetes Association. Multivariable logistic regression models, adjusted for potential confounders, were used to estimate risk of diabetes across quartiles of LCD score. RESULTS: Mean ± SD age of the study participants (44.4% men) was 40.5 ± 13.0 years. The median (25–75 interquartile range) of LCD score was 17.0 (12.0–21.0) and after a 3 year follow-up period, 123 (2.8%) incident cases of diabetes were ascertained. After adjustment for confounding variables, including age, sex, smoking status, physical activity, total calorie intake, saturated fatty acid, waist circumference, educational level, and family history of diabetes, the multivariable-adjusted ORs (95% CIs) of type 2 diabetes, comparing the highest with the lowest quartiles, were 2.16 (1.16–4.04) for total LCD score (P-value = 0.015), 1.81 (1.06–3.11) for animal-based LCD score (P-value = 0.029), and 1.47 (0.85–2.52) for plant-based LCD score (P-value = 0.160). CONCLUSION: Our findings suggest that a higher adherence to LCD, mostly with higher intakes of protein and fat from animal-source foods, can increase the incidence of diabetes; however, a plant-based low-carbohydrate dietary pattern is not significantly associated with risk of type 2 diabetes.