Researchers tested whether drinking a protein shake 30 minutes before breakfast could help pregnant women with gestational diabetes (a type of diabetes that develops during pregnancy) keep their blood sugar levels more stable. Sixty-two pregnant women in their third trimester either received a whey protein drink or a placebo every morning. The women who drank the protein shake had significantly lower blood sugar spikes after eating breakfast—about 20% lower in early pregnancy and 15% lower later on. Their blood sugar also stayed more stable throughout the day. This suggests that a simple, daily protein supplement before breakfast might help pregnant women with gestational diabetes avoid needing insulin injections.

The Quick Take

  • What they studied: Does drinking a whey protein shake 30 minutes before breakfast help pregnant women with gestational diabetes keep their blood sugar more stable?
  • Who participated: 62 pregnant women in their third trimester (last 3 months of pregnancy) who had been diagnosed with gestational diabetes. Women were at least 18 years old and had normal blood pressure.
  • Key finding: Women who drank the protein shake had blood sugar levels that were 20% lower one hour after breakfast in early pregnancy and 15% lower in late pregnancy, compared to women who got a placebo drink.
  • What it means for you: If you’re pregnant with gestational diabetes, drinking a protein shake before breakfast might help you avoid needing insulin shots. However, this is one study with a small group, so talk to your doctor before making changes to your routine.

The Research Details

This was a carefully designed experiment called a randomized controlled trial, which is considered one of the best ways to test if something actually works. The researchers split 62 pregnant women into two groups randomly—like flipping a coin to decide who got what. One group drank a whey protein shake (20 grams of pure protein) 30 minutes before breakfast every day for the last three months of pregnancy. The other group drank a placebo (a fake drink that looked and tasted the same but had no protein). Neither the women, their doctors, nor the researchers knew who was getting the real protein or the fake drink until the study ended—this is called “blinding” and it prevents bias.

The researchers measured blood sugar levels in two ways: in a controlled setting (like a lab) and in real life (at home). They used continuous glucose monitors—small devices that track blood sugar all day long—to get accurate measurements. They tested the women twice: once early in the third trimester and once later, plus at delivery.

This study design is strong because it controls for many things that could affect the results. The random assignment means the two groups should be similar in other ways, so any differences in blood sugar are likely due to the protein, not other factors.

The study design matters because gestational diabetes is serious—it can cause problems for both the mother and baby during pregnancy and birth. If a simple, safe protein drink could help control blood sugar without medication, it would be a big deal. The researchers used continuous glucose monitoring instead of just checking blood sugar a few times, which gives a much more complete picture of how blood sugar behaves throughout the day.

This study has several strengths: it was published in a top medical journal (Diabetologia), it was double-blinded (reducing bias), it used continuous glucose monitoring (very accurate), and it tested women in both controlled and real-life settings. However, the sample size was relatively small (only 62 women), and some women dropped out before finishing. The study was funded partly by a company that makes protein products, which is worth knowing about. The results were consistent across different measurements, which makes them more trustworthy.

What the Results Show

The main finding was that women drinking the whey protein shake had much lower blood sugar spikes after breakfast. One hour after eating, their blood sugar was about 20% lower in early pregnancy and 15% lower in late pregnancy compared to the placebo group when measured in controlled conditions. In real-life settings at home, the difference was smaller but still meaningful—14% lower early on and 8% lower later.

Beyond just the after-meal spike, the protein drink also helped keep blood sugar more stable throughout the day. The researchers measured this using something called “glycaemic variability,” which is basically how much blood sugar bounces up and down. Women in the protein group had less bouncing around, especially in early pregnancy. This is important because stable blood sugar is better for both mother and baby.

The effect was strongest in early pregnancy and got a bit smaller by late pregnancy, but it remained helpful. The women tolerated the protein drink well with no reported safety problems.

The study also looked at how much time women spent with blood sugar in the healthy range (between 3.5-7.8 mmol/L). In late pregnancy during real-life conditions, women drinking protein spent more time in this healthy range. The researchers measured several different ways of tracking blood sugar stability, and most of them showed improvement in the protein group. This consistency across different measurements makes the findings more believable.

Previous research has shown that protein can help slow down how quickly the body absorbs carbohydrates, which prevents blood sugar spikes. This study confirms that idea works specifically for pregnant women with gestational diabetes. It’s one of the first studies to test this approach in this specific population during the third trimester. The results align with what we know about protein’s effects on blood sugar in general, but this is important new evidence for pregnancy.

The study had some limitations worth knowing about. First, only 62 women participated, which is a relatively small group—larger studies might show different results. Second, some women dropped out before finishing, which could affect the results. Third, the study only tested one type of protein (whey) at one dose (20 grams), so we don’t know if other amounts or types would work better or worse. Fourth, the study was done in one country and may not apply to all populations. Finally, the study only lasted through pregnancy—we don’t know if the benefits continue after birth or if they prevent long-term complications.

The Bottom Line

If you have gestational diabetes, talk to your doctor about whether drinking a whey protein shake 30 minutes before breakfast might help you. The evidence suggests it may reduce blood sugar spikes and keep levels more stable, which could potentially help you avoid insulin injections. However, this should be part of a complete diabetes management plan that includes healthy eating, exercise, and regular monitoring. This is one study, so don’t make major changes without medical guidance.

This research is most relevant for pregnant women diagnosed with gestational diabetes who want to explore non-medication options for managing their blood sugar. It may also interest healthcare providers who treat gestational diabetes. This study doesn’t apply to women without gestational diabetes or those who are not pregnant. People with milk allergies or those who can’t tolerate whey protein should not use this approach.

The study measured changes over three months (the third trimester), so you would need to use the protein shake for at least several weeks to see if it helps you. Some women might see benefits sooner, while others might take longer. You should see improvements in blood sugar readings within 2-4 weeks if it’s going to work for you, but consistency is important.

Want to Apply This Research?

  • Log your blood sugar readings before and one hour after breakfast each morning. Track whether you drank the protein shake and note any patterns. Over 2-4 weeks, you should see if your after-meal blood sugar numbers are trending lower.
  • Set a daily reminder 30 minutes before your usual breakfast time to drink the protein shake. Make it part of your morning routine, like brushing your teeth. Consistency is key—the study showed benefits when women took it every single day.
  • Use continuous glucose monitoring if available, or check blood sugar with a meter before breakfast and one hour after eating. Track weekly averages to see the trend over time. Share your readings with your healthcare provider to decide if the protein is helping enough to avoid insulin or if other treatments are needed.

This research describes a clinical trial testing whey protein supplementation for gestational diabetes management. While the results are promising, this is one study with a limited number of participants. Gestational diabetes requires medical supervision and individualized treatment plans. Do not start, stop, or change any diabetes treatment without consulting your healthcare provider. This information is for educational purposes only and should not replace professional medical advice. Pregnant women should always work with their obstetric care team before making dietary changes or starting supplements.