This release from Newcastle University describes a very small study that sought to control type 2 diabetes in patients through a reduced-calorie diet and a weight-management program. The results showed that 12 of the 30 participants saw a resumption of normal insulin production that continued for six months, supporting the release’s claim of “reversing” the disease. But what about the other 18 patients? A study this small can hardly suggest its finding are applicable to all type 2 diabetes patients which, in effect, it does. And benefits observed after only 6 months may not be maintained over the longer term. The release also omitted discussion of harms and alternatives, and didn’t give us a good picture of how the study was conducted.
Rates of Type 2 diabetes have increased markedly in parallel with rates of obesity, especially in developed countries. It has long been recognized that diet, weight loss and exercise can improve the control of diabetes. Large studies investigating the impact of weight loss surgery have demonstrated that blood sugar results can return to normal after significant weight loss. It has also been shown that individuals who regain weight after surgery can then have blood sugars go up again and need to resume medications for diabetes.
Patients and their families may excitedly assume that the approach described in this release is right for them and alter their normal regimen in the treatment of their disease. But adhering to the diet discussed in this release will be very difficult for most people and is not without risks. And despite the release’s suggestion of universal benefit, a “reversal” of diabetes did not occur in the majority of patients. Patients should understand that context when weighing whether to embark on such a diet.
The release makes no mention of cost and while the diet changes, including diet shakes and vegetables, may not exceed the cost of a regular diet, the individualized weight management program for a half-year could represent additional costs for people not in the study, something of which readers should be reminded.
The headline on this release, along with the lede, states that diabetes can be reversed while the data provided only suggest that 12 of the 30 participants experienced a return of normal insulin production levels following adoption of a very low calorie diet. Given that this was such a small study, we fault the release for suggesting the results can be extrapolated to the universe of Type 2 diabetes patients. In cases like this, where the number of patients with diabetes is so large, semantics are important. At best, the release suggests that in this small study, only 40 percent of the participants experienced a remission in their disease for a period 6 months — which is not very long considering that most patients who lose weight will eventually regain it over the course of several years. Suggesting that the disease can be “reversed,” without qualifying that the result applies to a limited number of patients, is an exaggeration and far too great a conclusion for this study.
There is no mention of any harms that might arise from this approach. There are risks that come with very low calorie dieting — which was done for 8 weeks according to the release. Potential harms of extreme dieting should have been mentioned including whether there were any health issues in the 30 patients over the six months study period.
The most common side effect of very low calorie dieting is gallstones, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Minor, short-lasting side effects include fatigue, constipation, nausea and diarrhea. The Institute recommends that patients following a very low calorie diet that results in rapid weight loss should be monitored by a doctor.
The study the release is based on is indeed intriguing and certainly supports the idea of a better, larger research effort to test whether its findings are confirmed. But the verbiage used to describe the study’s outcome far exceeds what should be garnered from this research.
The release doesn’t paint a full picture of what happened in the study. For example, there is no explanation about the 18 patients in the study whose insulin production did not return to normal, something a thoughtful reader of the release might quickly wonder about. Throughout the release there is mention that the weight loss worked by removing fat from the pancreas, leading to improved release of insulin. One of our reviewers on this release, a clinician and associate professor at Harvard Medical school, thought that this should have been recognized as a hypothesis that is not well supported by a large body of literature. It is not that the pancreas is not producing insulin in Type 2 diabetes, rather it is not producing enough and the insulin being produced is being blocked, especially by the fat cells throughout the body. Losing weight decreases the amount of fat and improves insulin resistance — leading to improved sugars. The hypothesis proposed in this release also is inconsistent with a growing body of genetic studies pointing to the underlying mechanisms that are associated with the development of Type 2 diabetes. Diabetes is currently believed to be associated with a number of different genetic mechanisms, implying that the one mechanism implied in this release, even if true, may apply to only a fraction of patients with Type 2 diabetes.
The release doesn’t engage in disease mongering, but neither does it give us much context about Type 2 diabetes incidence. Because the release included a very important caveat about obesity and diabetes prevalence, we’ll give them the benefit of the doubt. “Individuals vary in how much weight they can carry without it seeming to affect their metabolism – don’t forget that 70% of severely obese people do not have diabetes,” according to the release.
The release does identify multiple funding sources and there is no suggestion of any conflict of interest.
There are alternatives to this diet that have been shown to correct blood sugar results in large studies — specifically weight loss surgery. This should have been mentioned.
Given that the approach of this study focuses on specific foods as key to maintaining weight, and that these foods are commonplace, one assumes that they are readily available in the marketplace.
The study addresses novelty through this statement: “The research is part of a growing body of evidence showing that people with Type 2 diabetes who successfully lose weight can reverse their condition because fat is removed from their pancreas, returning insulin production to normal.” We think that’s not quite appropriate positioning of the results. While it’s true that there is considerable evidence from studies of weight loss surgery that diabetes values can be normalized with significant weight loss, this release is also suggesting that it has proven that all diabetes patients can reverse the disease through diet alterations, and that the benefits are due to a reduction in fat in the pancreas. These claims go too far based on the small study size and a demonstrated 40 percent success rate.
We’re rating this category unsatisfactory for a number of reasons. First, the blatant claim that diabetes can be “reversed” rather than pushed into remission for 6 months based on results from 12 participants who represent less than half of those tested. Second, the lead investigator is first described as “world-renowned” while readers would be hard-pressed to recognize his name. The description of the funders touts its “world-class expertise,” a descriptor which, while it might be correct, offers readers little to help them understand this study.