Study suggests extreme calorie reduction may have same effect as bariatric surgery.
A new clinical study may change the way we think about type 2 diabetes. Traditionally, type 2 diabetes has been thought to be a non-curable chronic progressive condition. The pancreas’ beta cells will continue to decline with time and after 10 years more than 50% of individuals require insulin therapy. There is strong evidence that beta cell mass decreases over the course of diabetes.
Contrary to the traditional belief, bariatric surgery has been clearly shown to reverse type 2 diabetes. Following bariatric surgery, plasma glucose normalizes within a few days long before weight loss occurs. A clinical study from Newcastle University hypothesized that the sudden negative energy balance following bariatric surgery and decrease in intracellular fatty acid concentration in the liver is the cause of type 2 diabetes reversal. It is possible to restart the insulin producing beta cells in the pancreas through a consistent diet. The Newcastle team designed a clinical trial to test their hypothesis on negative energy balance effects on diabetes.
Eleven people participated in the study, which reduced their daily calorie intake to just 600 calories a day for two months. Study participants recruited were 35 to 65 years of age, A1c levels 6.5-9%, had diabetes for less than 4 years and a BMI of 25-45 kg/m2. Baseline parameters looking at beta cell function, insulin sensitivity, liver, and pancreatic fat content, and total body fat were recorded prior to the study. The individuals were started on a liquid diet of 510 calories per day and supplemented with three portions of non-starchy vegetables bringing up the total energy intake to 600 calories per day. They were matched to a control group without diabetes and then monitored over eight weeks. The diet was maintained for eight weeks then subjects returned to normal eating, but participants were educated on healthy portion size and eating.
The results of the study showed that beta cell failure and insulin resistance caused by type 2 diabetes can be reversed through a low-calorie diet. In the first seven days of the diet, fasting blood glucose and hepatic insulin sensitivity returned to normal with intrahepatic lipid decreasing by 30%. As the experiment progressed, beta cell function increased towards normal and pancreatic fat decreased. After the eight weeks of dieting, subjects lost an average of 15.3 kg(33.73 lbs)or 15% of initial body weight. Ten people were retested in three months after resuming their normal diet, seven remained free of diabetes.
From the study, we can conclude that excess lipid content in the liver and pancreas have a negative impact on normal insulin action and insulin secretion. An important point from the study is that individuals have different individualized tolerance to fat. Type 2 diabetes develops when a person crosses their personal fat threshold. There are some people who have a BMI of greater than 40 without developing diabetes, whereas, others can develop diabetes with a BMI of 25. The defects caused by diabetes can be reversed by substantial weight loss.
Roy Taylor, MD, director of the Newcastle Magnetic Resonance Centre at Newcastle University in England, added that, “We used the 600-calorie diet to test a hypothesis. What I can tell you definitively is that if people lose substantial weight by normal means, they will lose their diabetes.”
While the study showed that diabetes can be reversed by substantial weight loss, more research has to be done. The study size was very small and future research should investigate the effects of fat contents in the liver and pancreas and its effects on diabetes. The study also mimicked the sudden calorie reduction following bariatric surgery, which is a vigorous approach that is not appropriate for everyone. Future studies on whether a less rigorous diet done over a longer period of time can produce the same results seen. Overall, the study results can change our knowledge on the causes and progression of diabetes.
- Patients should be educated that diabetes could potentially be reversed through vigorous weight loss regimen.
- To ensure that patients are diabetes free after the diet regimen, it is very important to emphasize the importance of not regaining the weight through a healthy diet and portion size.
- Very low-calorie diet reduced the amount of fat in the pancreas and liver, which allowed insulin production and function to return to normal.
Lim, Ee Lin, et al. “Reversal of type 2 diabetes: normalisation of beta cell function in association with decreased pancreas and liver triacylglycerol.”Diabetologia 54.10 (2011): 2506-2514.; Pories, Walter J., et al. “The control of diabetes mellitus (NIDDM) in the morbidly obese with the Greenville Gastric Bypass.” Annals of surgery 206.3 (1987): 316.