Researchers are testing whether eating certain types of carbohydrates can help people with type 2 diabetes control their blood sugar better. The study will have 150 people with diabetes try two different eating plans for 12 weeks each: one following standard diabetes guidelines, and another that focuses on eating more “resistant starch” (a special type of carb that digests slowly) while reducing fast-digesting carbs. Scientists will measure how well each diet keeps blood sugar stable and check other health markers like cholesterol, brain function, and mood. This research could help doctors give better dietary advice to millions of people managing diabetes.

The Quick Take

  • What they studied: Whether eating a special diet with more slowly-digesting carbohydrates helps people with type 2 diabetes keep their blood sugar more stable compared to a standard diabetes diet.
  • Who participated: 150 adults with type 2 diabetes from multiple hospitals in China. Each person will try both diets in a crossover design, meaning they’ll experience each eating plan for 12 weeks with a 6-week break in between.
  • Key finding: This is a study protocol (a plan for research), not yet completed research. The main goal is to measure whether the optimized carb diet reduces blood sugar spikes after meals better than the conventional diet.
  • What it means for you: If results show the optimized carb diet works better, it could give people with diabetes a new, evidence-based eating strategy to manage their condition. However, results won’t be available until the study is completed and analyzed.

The Research Details

This is a randomized controlled crossover trial, which is one of the strongest types of nutrition research. Here’s how it works: 150 people with type 2 diabetes will be randomly assigned to start with either a conventional diet (following standard diabetes guidelines) or an optimized carbohydrate diet. They’ll follow their first assigned diet for 12 weeks, then take a 6-week break to let their body return to normal. After the break, they’ll switch to the other diet for another 12 weeks. This crossover design is powerful because each person serves as their own comparison—researchers can see how the same person responds to both diets, which reduces confusion from individual differences.

The optimized carbohydrate diet focuses on two main changes: increasing resistant starch (a type of carbohydrate that digests slowly) to 40 grams per day, and decreasing rapidly digestible starch (carbs that break down quickly and spike blood sugar). Both diets will have the same total calories and the same balance of protein, fat, and carbohydrates overall—the only difference is the type of carbs eaten.

The study is being conducted at multiple hospitals in Shanghai, China, and has been approved by ethics committees to ensure participant safety. Researchers will measure many health markers before, during, and after each diet period.

The crossover design is important because it allows researchers to see how each person’s body responds to different types of carbohydrates while controlling for individual differences. By having people try both diets, scientists can be more confident that any differences are due to the diet itself, not other factors. This design is particularly valuable for nutrition research because it requires fewer participants to get reliable answers compared to studies where different people try different diets.

This study has several strengths: it’s randomized (reducing bias), uses a crossover design (strong methodology), includes 150 participants (a reasonable sample size), measures multiple health outcomes (comprehensive), and is registered publicly before results are known (transparency). The study is being conducted at reputable medical centers and has ethics approval. However, this is a protocol paper describing the planned study, not the actual results yet, so we cannot evaluate how well the study was actually executed or what the findings show.

What the Results Show

This paper is a study protocol, meaning it describes the plan for research that hasn’t been completed yet. Therefore, there are no actual results to report. The primary outcome the researchers will measure is something called the ‘incremental area under the blood glucose curve’ (iAUC) after meals—essentially, how much blood sugar spikes after eating and how long it stays elevated. They will compare this measurement between the two diets to see which one keeps blood sugar more stable.

Once the study is completed and data is analyzed, researchers will determine whether the optimized carbohydrate diet (with more resistant starch and less rapidly digestible starch) produces smaller blood sugar spikes compared to the conventional diabetes diet. This is important because reducing blood sugar spikes is a key goal in diabetes management.

Beyond blood sugar control, the researchers plan to measure many other health markers, including cholesterol and fat metabolism, cognitive function (thinking and memory), mood and psychological well-being, appetite hormones, liver health, immune function, and inflammation markers. These secondary outcomes will provide a more complete picture of how different carbohydrate types affect overall health in people with diabetes. The study will also look at how the diet affects appetite and eating behavior, which could explain why one diet might be easier to follow than another.

Previous research suggests that resistant starch—the slowly-digesting carbohydrate emphasized in the optimized diet—may help improve blood sugar control and have other metabolic benefits. However, most previous studies have been smaller or shorter in duration. This study is designed to provide stronger evidence by testing 150 people over a longer period (12 weeks per diet) using a rigorous crossover design. The findings will help clarify whether resistant starch recommendations should become standard advice for people with type 2 diabetes.

Since this is a protocol paper rather than completed research, we cannot yet identify limitations in the actual execution. However, potential limitations to consider: the study is being conducted in China, so results may not apply equally to other populations with different genetic backgrounds or food cultures; the 12-week diet period may not be long enough to see all possible effects; and people’s adherence to the diets may vary, which could affect results. Additionally, the study cannot determine whether people will actually stick to the optimized diet long-term in real life.

The Bottom Line

This is preliminary research (a study plan), so no recommendations can be made yet. However, once results are available, they may support adjusting carbohydrate choices for people with type 2 diabetes. Currently, people with diabetes should continue following their doctor’s dietary advice and work with a registered dietitian for personalized guidance. If future results show benefits from resistant starch, it could become a recommended strategy—but this would need confirmation from additional studies and approval from medical organizations.

This research is most relevant to people with type 2 diabetes who are looking for dietary strategies to improve blood sugar control. It’s also important for healthcare providers, dietitians, and diabetes educators who advise patients on nutrition. People with type 1 diabetes, prediabetes, or those without diabetes should wait for results before considering whether findings apply to them. Individuals with digestive disorders that make resistant starch difficult to tolerate should discuss any dietary changes with their doctor.

Since the study hasn’t been completed yet, results won’t be available for several months to over a year. Once data collection is finished, researchers will need time to analyze results and prepare findings for publication. Typically, this process takes several additional months. Even after publication, it usually takes time for medical organizations to review evidence and update guidelines. Therefore, any potential changes to diabetes dietary recommendations based on this research would likely take 1-2 years or more to become standard practice.

Want to Apply This Research?

  • Track blood sugar readings (if using a glucose monitor) before and 2 hours after meals, recording the type of carbohydrate eaten (resistant starch sources like cooled potatoes, legumes, or special starches versus regular refined carbs). This creates a personal data set showing which carbs produce smaller blood sugar spikes for that individual.
  • Users could gradually increase resistant starch intake by adding foods like cooked-then-cooled potatoes, beans, lentils, or whole grains to meals, while reducing white bread, white rice, and sugary foods. The app could suggest specific food swaps and track daily resistant starch intake toward a 40-gram goal.
  • Establish a baseline of current blood sugar patterns and carbohydrate intake, then implement gradual dietary changes over 4-6 weeks while tracking blood sugar response, energy levels, digestion comfort, and appetite. Use the app to identify which resistant starch sources work best for the individual and produce the most stable blood sugar.

This article describes a planned research study that has not yet been completed or published with results. The findings described are theoretical and based on the study protocol. This information is for educational purposes only and should not be used to make changes to diabetes treatment or diet without consulting your healthcare provider or registered dietitian. People with type 2 diabetes should continue following their doctor’s current recommendations and work with qualified healthcare professionals before making significant dietary changes. If you have diabetes or are considering dietary modifications, please discuss any changes with your medical team first.