Researchers analyzed 27 studies involving nearly 2,900 people with type 2 diabetes to see if eating fewer carbohydrates helps control blood sugar. They found that low-carb diets do improve blood sugar levels in the short term, especially in the first three months, and help people lose weight. However, these benefits tend to fade over time. Interestingly, the study found that how well low-carb diets work may depend on a person’s cultural background and lifestyle, suggesting that one-size-fits-all diet advice might not be the best approach for everyone.

The Quick Take

  • What they studied: Whether eating fewer carbohydrates helps people with type 2 diabetes control their blood sugar levels, and whether the results are different for people in Eastern countries versus Western countries.
  • Who participated: Nearly 2,900 adults with type 2 diabetes across 27 different research studies. Seven studies included people from Eastern countries, and 20 included people from Western countries.
  • Key finding: Low-carb diets improved blood sugar control by about 0.29% (measured by HbA1c, a key diabetes marker) and lowered fasting blood sugar by about 7 mg/dL. The biggest improvements happened around 3 months, but then the benefits started to shrink over time.
  • What it means for you: If you have type 2 diabetes, a low-carb diet may help you control your blood sugar better in the short term, but you shouldn’t expect it to work forever without other lifestyle changes. Your cultural background and personal situation matter too, so what works for someone else might not work the same way for you.

The Research Details

This was a meta-analysis, which means researchers looked at 27 different studies that had already been completed and combined all their results together. Each of these 27 studies was a randomized controlled trial, which is considered the gold standard in medical research. In these trials, people with type 2 diabetes were randomly assigned to either eat a low-carb diet or a regular diet, and researchers tracked their health markers over at least 12 weeks.

The researchers searched three major medical databases (PubMed, Embase, and Scopus) for all studies published up until August 2024. They looked specifically at studies that lasted at least 12 weeks because they wanted to see both short-term and longer-term effects. They also compared results between studies done in Eastern countries (like China and India) and Western countries (like the United States and Europe) to see if cultural differences mattered.

By combining results from many studies instead of looking at just one, researchers can see the bigger picture and get more reliable answers. This approach is especially important for nutrition research because individual studies can sometimes give different results. By separating Eastern and Western populations, the researchers could check whether diet recommendations need to be different for different cultures, which is an important but often overlooked question.

This study is reliable because it combined results from 27 randomized controlled trials, which are the most trustworthy type of research. However, readers should know that the studies included varied quite a bit in how they defined ’low-carb’ diets—some allowed more carbs than others. The researchers also noted that none of the studies actually tested very-low-carb diets (under 10% of calories from carbs), so the findings really apply to ’low-to-moderate’ carb diets instead. The fact that benefits decreased over time suggests that people may have struggled to stick with the diet long-term.

What the Results Show

Low-carb diets did help control blood sugar in the short term. The main measure of blood sugar control (HbA1c) improved by 0.29%, which is a modest but meaningful improvement for people with type 2 diabetes. Fasting blood sugar (the level when you first wake up) dropped by about 7 mg/dL on average.

The biggest benefits appeared at the 3-month mark. At this point, people who ate fewer carbohydrates saw larger improvements in both blood sugar control and weight loss compared to those who ate more carbs. Weight loss was also greatest at 3 months, with an average loss that researchers noted but didn’t specify in the abstract.

However, these improvements didn’t stick around. As time went on beyond 3 months, the benefits started to shrink. This suggests that people either stopped following the diet as strictly, or their bodies adapted to the diet over time. By the end of the studies, the advantages of low-carb diets were much smaller than they were at 3 months.

The research revealed that cultural context appears to influence how well low-carb diets work. While the abstract doesn’t provide specific numbers for Eastern versus Western populations, the researchers emphasized that responses may differ based on cultural background. This is important because most nutrition research focuses on Western populations, and results might not apply equally to everyone. The study also found that the actual amount of carbohydrates people ate mattered more than just being ‘on a low-carb diet’—those who ate the fewest carbs saw the best results at 3 months.

This finding aligns with what many other studies have shown: low-carb diets can help with short-term weight loss and blood sugar control. However, this meta-analysis adds important nuance by showing that benefits fade over time, which explains why some people struggle to maintain results with low-carb diets long-term. The emphasis on cultural differences is relatively new and suggests that future research should pay more attention to whether diet recommendations need to be customized for different populations.

The studies included didn’t test truly very-low-carb diets (under 10% of calories from carbs), so we don’t know if more extreme versions would work better or worse. The definition of ’low-carb’ varied between studies, which made it harder to compare results. The research also doesn’t explain why benefits fade over time—it could be because people stopped following the diet, or because their bodies adjusted. Finally, while the researchers noted that cultural context matters, they didn’t provide detailed analysis of exactly how Eastern and Western populations differed in their responses.

The Bottom Line

If you have type 2 diabetes and are interested in trying a low-carb diet, research suggests it may help improve your blood sugar control and weight in the first 3 months (moderate confidence level). However, plan for the benefits to decrease over time, so you’ll need to combine it with other healthy habits like exercise and stress management to maintain results long-term. Work with your doctor or a dietitian to create a plan that fits your cultural background, food preferences, and lifestyle, since one standard low-carb diet doesn’t work the same way for everyone.

People with type 2 diabetes who are looking for ways to improve their blood sugar control should pay attention to this research. It’s especially relevant if you’re considering a low-carb diet as part of your diabetes management. However, this research is less relevant for people with type 1 diabetes or those without diabetes. If you’re taking diabetes medications, talk to your doctor before changing your diet, because lower carb intake might require adjusting your medication doses.

You can expect to see the biggest improvements in blood sugar control and weight loss within the first 3 months of following a low-carb diet. After that, benefits tend to level off or decrease, so don’t be discouraged if progress slows down. To maintain long-term benefits, you’ll likely need to combine the diet with other lifestyle changes and possibly adjust your approach over time based on what works for you personally.

Want to Apply This Research?

  • Track your daily carbohydrate intake (in grams) and your fasting blood sugar readings each morning. Set a goal to reduce carbs gradually and monitor whether your fasting blood sugar improves over the first 3 months. Record how you feel and any changes in energy levels to help identify what carb level works best for you.
  • Start by identifying which carbohydrate-containing foods you eat most often (bread, rice, pasta, sugary drinks, etc.) and gradually reduce portions or swap them for lower-carb alternatives. Rather than trying to make a drastic change overnight, aim to reduce carbs by 10-15% each week until you reach your target. Use the app to log meals and see patterns in how different foods affect your blood sugar.
  • Check in with your blood sugar readings and weight weekly for the first 3 months to see if the diet is working for you. After 3 months, shift to monthly check-ins since benefits tend to plateau. Also track whether you’re able to stick with the diet—if you’re struggling, adjust your carb target to a level that feels more sustainable. Share your data with your doctor every 3 months to see if medication adjustments are needed.

This research summary is for educational purposes only and should not replace professional medical advice. If you have type 2 diabetes and are considering changing your diet, especially if you take diabetes medications, consult with your doctor or a registered dietitian before making significant dietary changes. Low-carb diets may require adjustments to medication doses, and your healthcare provider needs to monitor your blood sugar levels during any dietary transition. Individual results vary based on genetics, lifestyle, medications, and other health factors.