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Dr. Peter Brukner OAM2 min read

Show me the evidence: Low carb and gestational diabetes

Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance that commences during pregnancy. It is a common condition that affects about 15% of women and is associated with poorer pregnancy outcomes as well as an increased likelihood of developing type 2 diabetes later in life.

The role of diet, and specifically low carbohydrate diet, although widely recommended, has not been extensively studied.

Major et al. subjected two groups of women with GDM to a low carbohydrate diet (below 42%) or high carbohydrate diet (over 45%). The low carbohydrate diet yielded better results; correct glycaemia levels were attained and there was rarely a need for further therapy with insulin. It was also demonstrated that in this group there were fewer neonates who were large for gestational age, fewer cases of macrosomia and fewer caesarean sections due to pelvic disproportion.

Citation: Major CA, Henry MJ, de Veciana M et al. The effects of carbohydrate restriction in patients with diet-controlled gestational diabetes. Obstet Gynecol 1998; 91: 600–604.

Peterson and Jovanovic showed in their 1991 study that postprandial glycaemic response is an individual feature and is precisely related to the content of the carbohydrates consumed in the meal. In order to reach lower glycaemic values the quantity of carbohydrates in the diet was reduced

Citation: Peterson CM, Jovanovic-Peterson L. Percentage of carbohydrate and glycemic response to breakfast, lunch, and dinner in women of gestational diabetes. Diabetes 1991; 40 (supl 2): 172––174.

A retrospective cohort study conducted in Israel and published n 2019 showed that a Paleolithic diet maintained during pregnancy may have a beneficial effect on glucose tolerance. It also may increase iron stores and hemoglobin levels.

Citation: Lavie M, Lavie I, Maslovitz S. Paleolithic diet during pregnancy—A potential beneficial effect on metabolic indices and birth weight. European Journal of Obstetrics & Gynecology and Reproductive Biology 2019; 242:7-11

A review paper published in 2019 concluded that the prevailing gestalt of the evidence demonstrates that the restriction of carbohydrates results in improved maternal glycemia.

Citation: Farabi SS, Hernandez TL. Low-carbohydrate diets for gestational diabetes. Nutrients 2019 Jul 27;11(8):1737. doi: 10.3390/nu11081737. PMID: 31357598; PMCID: PMC6723585.

All the studies have shown a low carbohydrate diet to be safe in pregnancy. What little research evidence exists tends to support the use of a low carb diet ,but clearly there is an urgent need for high quality RCTs to assess the effect of a low carbohydrate diet.