Researchers compared two different approaches to treating newly diagnosed type 2 diabetes: a modified traditional Japanese diet and a medication called canagliflozin. Over three months, both methods helped control blood sugar and improved how the body uses insulin. However, the diet worked differently than the medication. The diet was especially good at reducing fat in the bloodstream and improving how fat tissue handles insulin, but only when people lost weight. The medication improved blood sugar control without requiring weight loss. This study suggests that diet and medication may help diabetes in different ways, and choosing between them might depend on individual needs.

The Quick Take

  • What they studied: Whether a traditional Japanese diet and a diabetes medication called canagliflozin work differently to improve blood sugar control and how the body handles insulin, especially in fat tissue.
  • Who participated: 108 people who were newly diagnosed with type 2 diabetes and had never taken diabetes medication before. About half (53 people) followed a modified Japanese diet, and the other half (55 people) took canagliflozin pills. The study lasted three months.
  • Key finding: Both the diet and the medication improved blood sugar control. However, the diet was uniquely effective at reducing fat in the blood and improving how fat cells handle insulin—but only in people who lost weight. The medication improved blood sugar without requiring weight loss.
  • What it means for you: If you have newly diagnosed type 2 diabetes, both dietary changes and this medication can help. The diet may offer extra benefits for fat metabolism if you’re willing to lose weight, while the medication works regardless of weight changes. Talk with your doctor about which approach fits your lifestyle and goals.

The Research Details

This was a prospective observational study, which means researchers followed two groups of people forward in time and observed what happened. One group of 53 newly diagnosed diabetes patients followed a modified traditional Japanese diet for three months. The other group of 55 newly diagnosed patients took a medication called canagliflozin for the same period. Researchers measured various blood markers at the start and end of the study, including blood sugar levels, insulin levels, and fat levels in the blood.

The researchers paid special attention to something called “adipose tissue insulin resistance,” which is a fancy way of saying how well fat cells respond to insulin. They also looked at whether weight loss was connected to improvements in these measurements. This allowed them to see if the diet and medication worked through the same pathway or different ones.

Understanding how different treatments work is important because it helps doctors choose the best option for each patient. If a diet and a medication work through different mechanisms, they might be better for different people. This study is particularly valuable because it’s one of the first to show that diet can directly improve how fat tissue handles insulin, which is a key problem in type 2 diabetes.

This study has some strengths: it compared two active treatments (not just one treatment versus doing nothing), it measured multiple important markers, and it looked at the relationship between weight loss and improvements. However, it’s observational rather than randomized, meaning people chose which treatment they received rather than being randomly assigned. This could introduce bias. The sample size is moderate (108 people), and the study only lasted three months, so we don’t know about long-term effects. The study was published in a peer-reviewed scientific journal, which adds credibility.

What the Results Show

Both groups showed significant improvements in blood sugar control. Fasting blood sugar (the level when you haven’t eaten) decreased in both groups, and HbA1c (a measure of average blood sugar over three months) improved in both. Both groups also showed better insulin sensitivity, meaning their bodies used insulin more efficiently.

The key difference emerged when researchers looked at fat tissue specifically. The Japanese diet group showed reductions in free fatty acids (fat floating in the blood) and improved how fat cells handle insulin. The medication group did not show these specific improvements in fat metabolism. In the diet group, people who lost more weight had better improvements in blood sugar, insulin sensitivity, and fat cell function. In the medication group, weight loss wasn’t necessary for blood sugar improvements.

The researchers also found that baseline fat cell insulin resistance was the strongest predictor of who would improve most with the diet. People who started with worse fat cell function benefited the most from dietary changes.

Both treatments improved beta cell function (the cells that make insulin), suggesting they both help preserve the pancreas’s ability to produce insulin. The medication appeared to work through mechanisms that don’t depend on weight loss, possibly through direct effects on the kidneys and blood sugar regulation. The diet’s benefits were more tightly linked to weight loss, suggesting that losing weight is an important part of how the diet works.

This study adds new information to existing research. Previous studies have shown that both dietary interventions and SGLT-2 inhibitors (the class of medication canagliflozin belongs to) can help type 2 diabetes. However, this appears to be the first study to directly show that diet can improve how fat tissue handles insulin. The finding that these two approaches work through different pathways is novel and helps explain why different people might respond better to different treatments.

The study only lasted three months, so we don’t know if these benefits continue long-term. People weren’t randomly assigned to groups, so there could be differences between the groups we don’t know about. The sample size is moderate, so results might not apply to everyone. The study focused on newly diagnosed patients, so results might differ for people who’ve had diabetes longer. We don’t know how these approaches compare when used together. The study didn’t track what people ate in detail in the medication group, so we can’t be sure they didn’t also change their diet.

The Bottom Line

If you have newly diagnosed type 2 diabetes: (1) Both dietary changes and canagliflozin can help improve blood sugar control (high confidence). (2) A modified Japanese diet may offer additional benefits for fat metabolism if you can achieve weight loss (moderate confidence, based on this single study). (3) Canagliflozin can improve blood sugar control without requiring weight loss (moderate to high confidence). Discuss with your doctor which approach fits your lifestyle, preferences, and health goals.

This research is most relevant to people with newly diagnosed type 2 diabetes who haven’t started medication yet. It may also interest people with type 2 diabetes considering dietary changes versus medication. People with advanced diabetes or those already on multiple medications should discuss these findings with their doctor, as results may differ. This is less relevant to people with type 1 diabetes or those without diabetes.

In this study, improvements were seen within three months. However, the full benefits of dietary changes often take longer to develop—typically 3-6 months for significant weight loss and metabolic improvements. The medication showed effects within the study period. Individual results vary, and some people may see benefits faster or slower than others.

Want to Apply This Research?

  • Track weekly weight and fasting blood sugar levels (if you have a home monitor). Also note energy levels and how you feel. This helps you see if your approach is working and whether weight loss correlates with your improvements, similar to what researchers measured in this study.
  • If following a dietary approach: set a specific, achievable weight loss goal (like 5-10 pounds over 3 months) and track it weekly. Log meals to ensure you’re following the modified Japanese diet principles. If taking medication: take it consistently as prescribed and monitor blood sugar regularly. Either way, track how you feel and any changes in energy or symptoms.
  • Check in monthly with measurements of weight, blood sugar (if possible), and how you feel. After 3 months, review your progress with your doctor and discuss whether your chosen approach is working. If using the diet, pay attention to whether weight loss is happening and correlates with blood sugar improvements. If using medication, ensure blood sugar is improving even without weight loss. Consider switching approaches or combining them if you’re not seeing expected improvements after 3 months.

This research describes findings from a three-month study comparing two approaches to newly diagnosed type 2 diabetes. These findings should not replace medical advice from your healthcare provider. Before making changes to your diabetes treatment—whether starting medication, changing diet, or stopping any current treatment—consult with your doctor or diabetes educator. Individual results vary based on genetics, lifestyle, and other health factors. This study was conducted in a specific population and may not apply to everyone. If you have type 2 diabetes, work with your healthcare team to develop a personalized treatment plan based on your individual needs and medical history.