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Low carb, high-fat diet high in animal products raises the risk of Gestational Diabetes

Gestational Diabetes (GDM) is a specific variety of diabetes that only occurs during pregnancy. It is known as "Gestational Diabetes" because the pregnant person did not have diabetes prior to pregnancy but developed an inability to produce enough insulin while pregnant.

Usually this condition resolves after the child is born, but untreated GDM can cause complications for both the pregnant person and their child, including high blood pressure or preeclampsia (a life-threatening complication for the pregnant person) as well as abnormally large size for the child, which increases the risk of shoulder dystocia, cesarean delivery, stillbirth, and increased risk of developing type 2 diabetes later in life for both pregnant person and child.

Thus there's quite a bit of research on the impact of the pregnant person's diet in the early part of their pregnancy on the risk of GDM. We've seen that drinking sugar-sweetened beverages can increase the risk of GDM, and that an overall Mediterranean-style diet can help prevent GDM.

Back in 2018 we reported on a study performed in Australia that suggested that those who consumed carbohydrates in the lowest 25% of intake were 54% more likely to develop GDM than those who consumed carbohydrates in the highest 25% of intake.

Today's research, published in the British Journal of Nutrition (2021;126:1872-1880), goes a step further.

A team of researchers in China analyzed the dietary intake of nearly 1,500 pregnant persons between 6 and 14 weeks gestation who were expecting only one child. All had no history of chronic metabolic diseases, including diabetes of any kind.

The participants were interviewed in person by trained investigators, who helped them complete three 24-hour dietary recalls of 2 weekdays and 1 weekend day. The investigators used standard cups, bowls, measuring tools, and illustrative pictures of foods to most accurately measure the participants' consumption of foods based on a Chinese Food Composition database.

With this information, the researchers were able to analyze each participants' diet with respect to their carbohydrate, fat, and protein intake, down to types of carbohydrates, source of fat (animal vs. plant-derived), and protein sources (again, animal vs. plant). Each participants' diet was ranked according to the percentage of total calories from carbohydrates, fat, and protein to create an overall Low Carbohydrate Diet (LCD) score. This was on a scale of 0 to 30, with higher scores indicating a higher proportion of calories from protein and fat.

After calculating each participants' overall LCD, the authors further calculated an animal LCD score by calculating percentages of energy from carbohydrates, animal protein, and animal fat, and then performed similar calculations for plant sources of protein and fats.

Participants were subjected to an oral glucose tolerance test between 24 and 28 weeks gestation - a normal precaution in order to screen for GDM. Those who were diagnosed with Gestational Diabetes had their three dietary scores compared with those of the participants who did not to see if any of the three dietary patterns were linked with GDM.

To make the comparison the authors grouped the participants into four groups - from low to high scores - for each of the three dietary patterns. After taking into account characteristics including age, education, medical history, weight gain during pregnancy, and other variables, the authors found that compared to those at the lowest end of the scale, those who scored the highest in an animal-based Low Carbohydrate Diet were 28% more likely to develop Gestational Diabetes. On the other hand, a Low Carbohydrate Diet that was higher in protein and fats from plant sources was not significantly associated with GDM.

What this means for you

Note that the participants' intakes of carbohydrates, proteins, and fats (whether animal or plant sources) were on a range and were not characterized by exclusion: that is, while some participants may have been vegans, this study does not compare a vegan diet with an omnivorous or even pescatarian diet.

What this does show, similar to another study we reported on last year, is that a plant-forward diet - where plant-based foods, including grains, are prominent but animal proteins and fats are not necessarily excluded may help the pregnant person avoid Gestational Diabetes, which is good for both parent and child.

First posted: March 23, 2022