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MELBOURNE — In recent years, low-carbohydrate diets have gained popularity as a weight loss strategy and potential treatment for Type 2 diabetes. However, a new study reveals that low-carb eating patterns are linked to a long-term increase the risk of developing the condition.
The study by Australian scientists uncovers a surprising link between low-carb diets and an increased risk of diabetes. Researchers from Monash University and RMIT University followed over 39,000 adults for nearly 14 years to investigate this relationship.
The study, published in the journal Diabetes and Metabolic Syndrome: Clinical Research and Reviews, found that people who adhered to a low-carbohydrate, high-fat, and high-protein diet had a 20% higher risk of developing Type 2 diabetes compared to those who ate a more balanced diet. This finding challenges the commonly held belief that cutting carbs is universally beneficial for metabolic health.
“Eating food high in saturated fats can lead to weight gain but we know they also lead to insulin resistance which is one of the causes of Type 2 diabetes independently of weight gain,” explains Distinguished Professor Barbora de Courten in a media release.
Before you rush to restock your pantry with pasta and bread, however, it’s important to understand the nuances of this research. The relationship between low-carb diets and diabetes risk isn’t as straightforward as it might seem at first glance. The researchers also note that this is an observational study and cannot prove that low-carb diets directly cause an increased diabetes risk.
The study utilized data from the Melbourne Collaborative Cohort Study, which recruited participants aged 40-69 between 1990 and 1994. Researchers analyzed dietary information collected at the start of the study and tracked new cases of diabetes reported by participants over the following years.
The researchers used a scoring system called the low-carbohydrate diet (LCD) score to measure how closely participants followed a low-carb eating pattern. This score was based on the percentage of total calories coming from carbohydrates, fat, and protein. A higher score indicated a diet lower in carbs and higher in fat and protein. The study divided participants into five groups based on their LCD scores.
Interestingly, the group with the highest LCD scores (meaning they ate the fewest carbs) consumed about 37.5% of their calories from carbohydrates. In contrast, the group with the lowest LCD scores got about 55.4% of their calories from carbs. To put this in perspective, many popular low-carb diets recommend getting less than 26% of calories from carbohydrates, which is even lower than the highest LCD score group in this study.
It’s important to note that not all low-carb diets are created equal. The study found that people with higher low-carb diet scores tended to consume more saturated fat and less fiber than those with lower scores. This suggests that the quality of fat and carbohydrates in the diet may be just as important as the quantity when it comes to diabetes risk.
The study also found some differences in lifestyle factors across the low-carbohydrate diet score groups. For example, the group with the highest scores had a higher proportion of current smokers, individuals with obesity, and lower physical activity levels compared to other groups – known risk factors for Type 2 diabetes.
When the researchers accounted for body mass index (BMI) in their analysis, the relationship between LCD score and diabetes risk disappeared. This suggests that the increased risk of diabetes associated with low-carb diets may be largely explained by differences in body weight.
“For people who don’t have diabetes, a balanced diet is the best choice,” de Courten says. “We need to remember that not all carbohydrates are equal. The kind of carbs you want to avoid are refined sugars such as soft drinks, juices, white rice, white bread and replace them with unprocessed carbs rich in fiber like grains, brown rice and legumes.”
“And eat more of healthy mono- and poly-unsaturated fats such as avocados, nuts, olive oil and fatty fish like salmon.”
The researchers note several limitations of their study, including its reliance on self-reported dietary data and the fact that they only measured diet at the beginning of the study period. They caution that eating patterns may have changed over time, which could affect the results.
As with any dietary change, it’s important to consult with a healthcare provider or registered dietitian before making significant shifts in your eating habits. They can help you develop a personalized nutrition plan that takes into account your individual health needs and risk factors.
This study serves as a reminder that there’s no one-size-fits-all approach to nutrition. While low-carb diets may be effective for short-term weight loss, their long-term impacts on health are still being understood. As always, a balanced diet, regular physical activity, and maintaining a healthy weight remain the cornerstones of diabetes prevention.
Note: An earlier version of this story mentioned Atkins and keto diets. While these are known low-carbohydrate diets, they were not specifically mentioned in the journal paper and are not representative of the diets followed in this study. We have removed the mentions of these specific diets from our text.
Paper Summary
Methodology
The researchers used data from the Melbourne Collaborative Cohort Study, which followed 39,185 adults 40-69 years of age for almost 14 years. Participants filled out food frequency questionnaires at the start of the study, which were used to calculate their LCD scores. The researchers then tracked who developed Type 2 diabetes over the follow-up period.
Key Results
People in the highest LCD score group (eating the fewest carbs) had a 20% higher risk of developing Type 2 diabetes compared to those in the lowest LCD score group. However, this increased risk disappeared when the researchers accounted for BMI, suggesting that body weight plays a crucial role in this relationship.
Study Limitations
The study relied on self-reported dietary information, which can be inaccurate. Additionally, diabetes cases were self-reported, although most were validated by doctors. The study also couldn’t distinguish between different types of carbohydrates (like whole grains vs. refined grains) or between plant and animal sources of protein and fat.
Discussion & Takeaways
This study highlights the complexity of nutrition research and the importance of considering overall dietary patterns rather than single nutrients. While low-carb diets may lead to short-term weight loss, their long-term effects on health may be less beneficial. The findings suggest that the quality of fats and proteins consumed in place of carbohydrates, as well as overall calorie balance and body weight, are crucial factors in determining diabetes risk.
Funding & Disclosures
The Melbourne Collaborative Cohort Study was funded by VicHealth, Cancer Council Victoria, and the Australian National Health and Medical Research Council. The authors declared no conflicts of interest.
You do NOT have to eat saturated fat on a keto diet!
“Interestingly, the group with the highest LCD scores (meaning they ate the fewest carbs) consumed about 37.5% of their calories from carbohydrates.” So about a 1/3rd of calories from carbs. What this study tells us then is a balanced diet causes increased risk of diabetes. Brilliant!
Useless study/article. So they examined people not actually doing Keto and somehow extrapolated that Keto is bad.
On no planet is 37.5% of calories from carbohydrates considered “ketogenic”
I don’t believe it. Benn on the diet several times, all with success, and I’m far from diabetes… same with friends, too and we’re all in our 50s.
Never mind the fact that they admit that after controlling for BMI, there is no increased risk for T2 diabetes from their data. One look at the methodology, and you can throw out the whole study.
The participants filled out ONE food frequency questionnaire at the BEGINNING of the study. Then they divided the people into their LCD groups based on that questionnaire and checked back 14 years later to see who had T2 diabetes.
A lot can change about people’s eating habits in 14 years (especially as people age and as trends in diet advice come and go), yet none of those changes are accounted for in the study because they didn’t track diet THROUGHOUT the study. They don’t know what people ate during that time, so they can’t make ANY diet-related conclusions.
Either this study was conducted by complete imbeciles, or it’s intended to mislead. Any time an article presents conclusions based on a study, we MUST examine the study’s sample size, methodology, and (perhaps most important) its source of funding.
100% spot on. I wonder who funded this study? Some big food processor, Big Pharma, etc.
It comes down eating a healthy diet , that includes all things in moderation and making sure you keep moving, there no magic diet to long term weight lose. To much pr to little of anything will cause problems.
A Low carb diet literally has put my diabetes on remission…
This article is absurd. Headline warns against keto diets, and only at the very end of the article do you reveal that the cause of the increased risk of diabetes was actually obesity and smoking rather than anything at all to do with the amount of carbohydrates consumed.
So…the article actually tells us that people who didn’t follow a low-carb diet as intended developed Type-2 diabetes. This has been known since the beginning and was preached by Dr. Atkins. His diet worked only if you kept carbs lower than approximately 20 g per day to keep the body in a state of ketosis. Otherwise, the weight would return and other health factors such as cholesterol would worsen.
This article is misleading and probably funded by General Mills or some other giant processed food manufacturer.
FYI: The Type 1 Diabetic diet is low carbohydrate; as such, the need for dense protein, the major metabolic fuel to repair cells, is paramount. It could be said the original Keto diet was that recommended for diabetics. This article is specious.
The article actually says there is no effect of low carb vs. higher % carbs. It pretty clearly states that the adjustment for hip to weight and BMI is what accounts for the 20% difference.
Perhaps you should consider the idea that people who are heavier are more likely to go on a low carb diet to lose weight, and studying the cohort of those people who decide to go on the diet vs. not would be more relevant.
Maybe your headline should’ve been “study finds that people who go on a low carb diet are generally heavier at the start than people who don’t”.
If you are eating 37% of calories from carbs you are not in ketosis nor eating a keto diet. I lost 67 lbs and kept it off for over 5 years while getting off all prescription meds.
Why to you publish this garbage?
It would be absurd to call these lies inaccuracies or mistakes. Do your own research and come to your own conclusions.
My brother has done Keto for 5 years and has never been healthier in his
Exactly. Consumption of high amounts of saturated fats can lead to insulin resistance. Stop listening to YouTubers who are telling you to eat bacon and butter just so that they get clicks.
Cut carbs and eliminate sugar from your diet to save your life and reverse diabetes. This article explains there is no evidence linking proteins and fats to insulin resistence, just that obesity and smoking leads to diabetes. This article gives no explanation of why to eat grains and rice. In actual reality you should not eat grains. You will live much longer on an animal based diet. Eliminate sugar, glucose and processed foods to save your life. And this means a balanced diet is eggs, butter, bacon, steak, fiah, and other unprocessed meats. Lucky us.
its already proven that natural and organic fats, not processed, INCLUDING bacon and butter, lean the body out and reducing fat unnecessary fat storage.
*Studies paid for by the sugar and medical industries…
Maybe you missed the comment in the article that accounting for BMI and another physical factor that is associated with diabetes risk mitigated any increased risk for low carb diet and diabetes. That shouldn’t be a surprise – that the average person on LCD is starting from a heavier point and trying to lose weight. So what exactly is your “exactly” to – the misleading title?
>>However, this increased risk disappeared when the researchers accounted for BMI<<
Follow that? When the two cohorts were adjusted for the effect of weight/BMI on diabetes risk, the low carb diet group didn't show any increased risk for diabetes. The actual study says a combination of BMI and waist to hip ratio, not just BMI. Both of these are long known.
So, now you take from that you sitting in your own chair since you can't get magically bigger all of the sudden, the study suggests if you went to low carb diet, you'd have no increased risk. I guess stating that in a headline won't get any hits from vegans and people on keto (I'm neither of those – it got my attention solely because it didn't make sense and I'd figure out who had bias and made up such a finding. Turns out they didn't – this site just decided to use a misleading headline).
This study is garbage. What the “researchers” describe as “low carb” isn’t low carb at all. The participants consumed over 37% of their calories from carbs as compared to 55%. A true low carb diet virtually eliminates carbs and splits the calories evenly between good, saturated fat and protein. Insulin resistance decreases and many of those with type 2 diabetes recover.
Please explain the process that high dietary fat intake leads to insulin resistance.
Doctors aren’t just “Youtubers” friend. They’re coming out in droves against the established medical industry and how they aren’t trying to cure their patients, and the diabetes problem is the worst one. Try reading “The Obesity Code” by Dr. Jason Fung. Insulin resistance is caused by too much insulin (the opposite of how they treat diabetics!), which is caused by insulin-spiking foods like sugar, carbs, refined foods, and a variety of chemicals, dyes, and artificial sweeteners, NOT fat.
I went keto back in February 2021 and then carnivore September 2022. I regularly get a NMR lipid profile done. I have went from insulin resistant to insulin sensitive. I am by far not a one off. I have never encountered anyone getting results in the opposite direction.
Absolute nonsense. My “type two” is now under control because of my Keto diet, and I’ve lost 100 pounds in 19 months. Most of these studies are nothing more than questionnaires and surveys.
Pretty weak methodology and controls.