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Real Food For Gestational Diabetes: What You Need To Know

By: Lily Nichols, RDN, CDE, CLT, author of Real Food for Gestational Diabetes

Gestational Diabetes Diet

Gestational diabetes is never part of any mom’s plan . . .

But it is the most common complication of pregnancy, affecting up to 18% of pregnant women. Yet there are many misconceptions about this diagnosis, both in conventional health care and the integrative medicine world. As a registered dietician/nutritionist and certified diabetes educator who specializes in gestational diabetes, I’m going to clear up some of the confusion for you today.

Whether or not you have gestational diabetes, this post will help you understand how it develops and why it’s important to maintain normal blood sugar (for all pregnant women, really). I’ll also be sharing why the typical gestational diabetes diet fails and why a real food, nutrient-dense, lower carbohydrate approach is ideal for managing gestational diabetes.

What is Gestational Diabetes?

Gestational diabetes is usually defined as diabetes that develops or is first diagnosed during pregnancy. However, it can also be defined as “insulin resistance” or “carbohydrate intolerance” during pregnancy.

I prefer to rely on the latter description because, at the end of the day, gestational diabetes is the result of insulin resistance, which means a woman is unable to tolerate large amounts of carbohydrates without experiencing high blood sugar. Technically all women experience some degree of insulin resistance during pregnancy as it’s a natural metabolic shift that serves to shunt glucose and nutrients to a growing baby.[1] This means, even if you haven’t been diagnosed with gestational diabetes, it’s helpful to understand how and why your metabolism changes during pregnancy (and how certain dietary changes can help ensure the health of your baby).

From a biological perspective, slight insulin resistance is incredibly important since it allows a baby to survive even if a pregnant woman experiences famine or short periods of starvation. However, in our modern world where food is rarely scarce and refined carbohydrates are everywhere, this adaptation can work against us. This is especially true if a woman already has some level of insulin resistance before becoming pregnant, which is becoming more common.[2]

Why Early Screening for Gestational Diabetes is Helpful

In years past, it was thought that the elevated blood sugar levels seen with gestational diabetes only begin to occur in the second and third trimester, when placental hormones are at their peak and insulin resistance spikes. This is why gestational diabetes is classically screened for around 24-28 weeks of pregnancy.

However, researchers have now found that gestational diabetes can be predicted earlier, by relying on a blood test called hemoglobin A1c (for short, A1c). In one study, a first trimester A1c reading of 5.9% or greater accurately predicted the development of GD 98.4% of the time.[3] That means, for these women, gestational diabetes wasn’t just a phenomenon of placental hormones, it was actually preexisting prediabetes (an A1c of 5.7%-6.4% indicates prediabetes). As their pregnancies progressed, their insulin resistance got more severe, as a natural result of placental hormones and weight gain, resulting in elevated blood sugar.

Moreover, gestational diabetes is increasingly believed to be an early indicator for the later development of diabetes, which means a woman’s insulin resistance continues or worsens years after they give birth. Women who have gestational diabetes have a 7-fold higher risk of developing type 2 diabetes later in life.[4]

Can Gestational Diabetes be Prevented?

Not all women with gestational diabetes have preexisting issues with glucose tolerance or insulin resistance, but research does show that wise preconception practices may prevent some cases of gestational diabetes. One study found that the combination of not smoking, exercising 150 minutes or more per week, and healthy eating reduced the risk of gestational diabetes by 41%.[5] Another showed that women who regularly exercised prior to conception and through 20 weeks gestation had a 49-78% reduced risk of developing gestational diabetes.[6] Adequate protein consumption during the first trimester may also protect against the later development of gestational diabetes.[7]

Maintaining a healthy weight preconception is also crucial, since being overweight at conception more than doubles the risk of gestational diabetes. For women with a body mass index (BMI) greater than 35, the risk of gestational diabetes is five times greater than a woman at a healthy weight, most likely because insulin resistance tends to go up at higher body weight.[8]

Vitamin D deficiency has also been associated with gestational diabetes (and, not surprisingly, insulin resistance). One study found that women who were deficient in vitamin D had a 3.7-fold increased risk of GD compared to women with normal levels.[9]

Gestational diabetes is never part of any mom’s plan... how can one approach it with real food? In this post Lily Nichols RDN, CDE, CLT, explains the details on gestational diabetes, how to prevent it, and how moms can feed themselves wholesome foods while treating gestational diabetes.

What’s the Problem with High Blood Sugar During Pregnancy?

Some people argue that since all women have some degree of insulin resistance during pregnancy, we shouldn’t make such a big deal out of gestational diabetes. However, there are significant risks to a baby exposed to high blood sugar during development, including:[10]

  • Various birth defects (high blood glucose is a teratogen[11])
  • Macrosomia (being born large at birth)
  • Shoulder dystocia (Shoulders of large babies can dislocate or become stuck during vaginal delivery. This may lead to a broken clavicle or neurological damage to the infant or a medical emergency for the mom.)
  • Hypoglycemia (baby’s blood sugar is too low at birth, which can be life threatening)
  • Jaundice
  • Permanent changes to a child’s metabolism

The final point is one I find extremely concerning. Essentially, if a fetus is exposed to high blood sugar, the fetal pancreas is forced to produce excessive amounts of insulin to maintain normal blood sugar.[12] That leads to the unnatural accumulation of fat, especially around the midsection, and hyperplasia of the fetal pancreas, both of which predispose the baby to insulin and blood sugar regulation issues later in life.[13] This has been referred to as “fetal programming” or “intrauterine programming.”

In fact, children exposed to gestational diabetes in the womb have a 6-fold higher risk of blood sugar problems at adolescence, including impaired glucose tolerance and type 2 diabetes.[14] They are also at a much higher risk for becoming overweight during their lifetime.[15] However, we know moms who maintain good blood sugar control throughout their pregnancies lessen these risks.[16]

Even Mildly Elevated Blood Sugar Matters

What is not as widely discussed is the fact that some of the problems associated with gestational diabetes can occur even in fairly “mild” cases.

A high number of women with gestational diabetes who do maintain what’s considered “good blood sugar control” still deliver babies with complications, which has led some researchers to reexamine what’s considered “normal” blood sugar during pregnancy.[17]

The landmark Hyperglycemia and Adverse Pregnancy Outcomes study (HAPO), which studied 23,316 women with gestational diabetes and their infants, found that even mildly elevated fasting blood sugar levels were linked to high insulin levels in infants at birth and macrosomia.[18] For example, women with an average fasting blood sugar of 90mg/dl or less had a large baby 10% of the time compared to 25-35% in women whose average fasting blood sugar was 100mg/dl or higher.

With this in mind, it’s likely that some of the negative effects of gestational diabetes on fetal programming may be occurring to mothers who experience only slightly elevated blood sugar.

So if you’ve been diagnosed with gestational diabetes, you might be interested to see how your doctor’s blood sugar targets align with “normal” blood sugar levels in other pregnant women in the chart below.


How is Gestational Diabetes Managed?

The primary treatment for gestational diabetes is diet and exercise. When those two aren’t enough to bring the blood sugar levels down to normal, a woman may need insulin or medication.

Many women would rather make dietary changes to control their gestational diabetes, than jump right to medicine (and most doctors feel the same way). Sadly, the conventional nutrition advice for gestational diabetes often fails to be enough.

Why the Typical Gestational Diabetes Diet Fails

When I first started working in prenatal nutrition, I was shocked to see that most women with gestational diabetes are given a very high carbohydrate diet with a minimum of 175g of carbohydrates per day.

At the time, since this was the accepted norm, I implemented this diet therapy for my patients. But their blood sugar numbers were not improving and, in some cases, got worse. Often, much to their disappointment, my patients had to start medication or insulin in order to control their blood sugar. (Side note: Medicine and insulin are useful tools for controlling blood sugar, but I believed we could do more nutritionally before resorting to them.)

This left me wondering, “Did they fail diet therapy, or did diet therapy fail them?”

After all, gestational diabetes is called carbohydrate intolerance for a reason. Carbohydrates are the primary macronutrient that raises the blood sugar, so why are we suggesting they eat lots of carbohydrates?

The primary reason clinicians are afraid to endorse a lower carbohydrate diet for pregnancy is that they’ve been given outdated information regarding ketosis. This topic is so complex that I devote an entire chapter to in my book, Real Food for Gestational Diabetes. But the short answer is that low-level nutritional ketosis is common during pregnancy, does not carry the same risks as starvation ketosis or diabetic ketoacidosis, and does not negatively impact the brain development of a baby.[19]

What Level of Carbohydrates is Best?

There will likely always be controversy around the ideal level of carbohydrates a woman should consume during pregnancy and frankly, I believe it will vary woman-to-woman based on her blood sugar control. But, in general, I find most women with gestational diabetes benefit from a diet that has less than 175g of carbohydrates per day.

My approach is to have a woman monitor her blood sugar while eating her usual diet (using a home glucose monitor) to get a baseline of how food affects her blood sugar. Then her diet can be adjusted to suit her individual glucose tolerance. A slightly lower-carbohydrate diet is both safe and efficacious, provided that a woman is consuming adequate calories.

In fact, studies have shown that a low-glycemic index diet reduces the likelihood a woman will need insulin by fully 50%.[20] This makes a real food diet ideal for managing gestational diabetes, since it generally avoids high-glycemic foods, like processed and refined carbohydrates.

(Some researchers even believe that our modern diet, high in refined carbohydrates, may be at least partly to blame for the rising rates of gestational diabetes.[21])

How to Proactively Manage Your Blood Sugar During Pregnancy

So, what can you do to maintain normal blood sugar during pregnancy? Below are some simple tips you can implement.

  • Request getting your HbA1c (hemoglobin A1c) measured with your first trimester labs to get a better idea of your baseline blood sugar control. That way, you can take action earlier in your pregnancy if you need to.
  • Ask to have your vitamin D levels measured (25-hydroxy vitamin D), so you can correct deficiency if it’s present. Depending on where you live, time of year, and time spent outdoors in sunlight, you may need to add a vitamin D supplement to meet target levels.[22]
  • If you have gestational diabetes, monitor your blood sugar in the morning (fasting) and after each meal to learn your body’s unique pattern and response to different foods (and combinations of food). Adjust your diet and exercise levels accordingly, knowing that carbohydrates tend to raise your blood sugar the most, fat and protein tend to stabilize your blood sugar, and exercise tends to lower your blood sugar.
  • Emphasize foods with plenty of fat and protein, both of which stabilize, rather than directly raise, the blood sugar. Pasture-raised meat (including organ meat), poultry, eggs, wild-caught fish, full-fat cheese, heavy cream, nuts, seeds, avocados, olives, butter, and some coconut products fit into this category.
  • Embrace low-glycemic sources of carbohydrates, like non-starchy vegetables (lots of these!), nuts, seeds, and low-sugar fruit (like berries). If you choose to consume dairy products, opt for full-fat Greek yogurt, cheese, heavy cream in lieu of milk and regular yogurt.
  • Reduce your intake of sugars, added or naturally-occurring, from things like juice (yes, even 100% organic, fresh-squeezed), sweetened drinks (like soda or sports drinks), desserts, honey, maple syrup, and dried fruit.
  • Become aware of which foods are the most concentrated sources of carbohydrates and watch your portion sizes. Avoid refined carbohydrates, like cereal and pasta.
  • When you consume starches, such as sweet potatoes or winter squash, eat them in small portions in combination with foods that are also high in fat, protein, and/or fiber to reduce their glycemic impact. For example, it’s better for your blood sugar levels to have a servings of sweet potatoes alongside grass-fed beef, sauteed spinach, and butter rather than by itself.
  • Avoid large portions of carbohydrates at one time to prevent blood sugar spikes. In other words, spread your servings of carbohydrate-containing foods throughout the day. It’s far better to have fruit as a snack twice per day than to have a large fruit salad in one sitting.
  • Exercise regularly. Even the conservative American Congress of Obstetricians and Gynecologists (ACOG) suggests pregnant women exercise 30 minutes per day (unless complications arise).[23] Resistance exercise is particularly helpful at reducing blood sugar levels.[24]

Although getting diagnosed usually isn’t welcomed news . . .

Gestational diabetes is a unique opportunity for you to focus on your self care, and in doing so, ensure your baby gets the best start in life. A real food approach is ideal for gestational diabetes, because it emphasizes nutrient-dense foods that provide a baby with all the critical nutrients for growth, while also minimizing blood sugar spikes.

Knowledge is power. If you discover that you have gestational diabetes, consider it a blessing in disguise. You can take steps to proactively manage it during your pregnancy and continue those same lifestyle habits postpartum to prevent type 2 diabetes later in life.

Remember, moms with gestational diabetes who keep their blood sugar levels at normal levels have no higher risk of complications.





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