Evidence Low-Carb Diets May Help Treat Insulin Resistance

Being overweight or obese increases your risk of developing type 2 diabetes and cardiovascular disease (CVD). Moreover, studies have shown that following a low-carbohydrate diet can help improve some elements of glucose metabolism and insulin sensitivity in individuals with type 2 diabetes.

However, there is some controversy around whether low-carb diets are actually effective for treating insulin resistance (IR). To address this question, researchers from the University of Toronto looked at the diet habits of more than 13,000 men and women aged 35 to 55 and whether their carb intake affected their risk of developing type 2 diabetes.

Their findings, published in the journal Diabetes, suggest that low-carb diets are indeed associated with lower odds of developing type 2 diabetes. What’s more, following a low-carb diet for more than three months may help improve insulin sensitivity in people with insulin resistance.

How Does the Study Work?

To determine how much weight gain and whether this was accompanied by any change in diabetes risk, the team analyzed the nutrition questionnaire data gathered from the Canadian Health Survey and linked these to the electronic medical records from the Canadian Institute for Health Information. This information was then linked to the Nova Scotia Health Insurance Plan, which provides coverage for most healthcare needs in the province of Nova Scotia (NS), Canada.

The researchers first examined the baseline characteristics of the participants and the rates of insulin resistance, defined as HOMA-IR ≥ 2.8, in the group as a whole. They then compared this to the characteristics of participants within three groups: 

  • those that followed a low-carb diet (≤30 g of carbohydrates per day) for at least three months and
  • those that ate a high-carb diet (\>30 to ≤100 g of carbohydrates per day)
  • those that did not follow either of these dietary patterns.

They found that people who followed a low-carb diet or who were on a low-carb diet for at least three months had an 18% lower risk of developing type 2 diabetes compared to people with a high-carb diet or those not on a diet. The odds of developing type 2 diabetes were 44% lower in those following a low-carb diet than in those on a high-carb diet.

The researchers then examined the association between carb intake and diabetes risk in more detail, finding that the lowest risk of diabetes was observed among those eating the least amount of carbohydrates. These data suggest that following a low-carb diet may help prevent type 2 diabetes in people with insulin resistance.

What Did the Researchers Find?

When the dietary pattern was examined over the course of three years, the team found that people who were on a low-carb diet at baseline had the lowest likelihood of developing diabetes. This pattern was also associated with a lower risk of developing prediabetes and T2DM. Additionally, the data showed that the longer someone followed a low-carb diet, the lower their diabetes risk was. This study did not examine why some people develop diabetes while others do not, but the data show that following a low-carb diet may help prevent and treat diabetes. Moreover, this research does not indicate that a low-carb diet can cure diabetes; however, it does show that it may delay or prevent its progression.

Many factors affect an individual’s risk of developing diabetes, including age, sex, race, socioeconomic status, and body weight. To account for these differences, the team also examined the association between diet and diabetes risk stratified by sex, age, and BMI. They found that the association between diet and diabetes risk varied by these subgroups, but, overall, people who followed a low-carb diet had a lower risk of developing diabetes.

What Does This Mean For You?

This research shows that some people who eat a low-carb diet may have lower odds of developing type 2 diabetes. This evidence suggests that people with insulin resistance may be a population that could benefit from a low-carb diet. Moreover, if you are following a healthy diet and exercise routine, you may be experiencing positive health benefits that could be attributed to your diet choices. More studies are needed to corroborate these findings and to determine whether a low-carb diet is beneficial to other health outcomes.