In 2003, Pixar introduced us to a vegetarian shark named Bruce in Finding Nemo whose slogan was: “Fish are friends, not food.” At the time, we laughed. But perhaps Pixar was right about this idea- The idea that not just fish, but all animal proteins are better if they go unconsumed by us, humans. Recent studies and scientific research have concluded that, in fact, plant-based diets (vegan and vegetarian) are effective in managing the effects of diabetes. Today, I will discuss an evidence-based case report from the Indonesian Journal of Internal Medicine titled “Plant-based Diet for HbA1c Reduction in Type 2 Diabetes Mellitus: an Evidence-based Case Report” which discusses this exact issue.

There is no doubt that diabetes, which can lead to more life threatening health issues, has continued to take numerous lives every day, especially in America. The Center for Disease Control and Prevention lists heart disease as the #1 cause of death in 2017, followed by diabetes as the #7 leading causes of death. Diabetes, which is a gateway to cancers, heart disease, and heart failure, is a condition that can be dealt with simply before it manifests into something more dangerous. We have been told by professionals again and again that we can reduce the risk of getting diabetes by simply eating well and by exercising regularly, but still, most of America still chooses to ignore this.

There are two forms diabetes takes: Type 1 and Type 2. According to Mayo Clinic, Type 2 diabetes is considered a chronic condition that affects the way your body metabolizes glucose by either resisting the effects of insulin (a hormone which regulates the movement of sugar into cells), or by not producing enough insulin to maintain normal glucose levels. Type 2 diabetes is traditionally known as adult-onset diabetes. However, more children today are being diagnosed with type 2 diabetes,  which is most likely due to the rise in childhood obesity. Although no cure exists for this condition, losing weight, exercise, and healthy eating can help in managing the disease. Without proper management, diabetes medication or insulin therapy is necessary to manage blood sugar. 

Changes in nutritional diet has been said to be one of the key aspects in managing type 2 diabetes mellitus. The central principle of nutritional management of type 2 diabetes is a hypocaloric diet, which is a low-calorie diet. It has been said that those trying to manage type 2 diabetes should limit carbohydrate intake, limit saturated and trans fats, and limit cholesterol. The main idea is for overweight individuals to reduce energy intake. Despite this, one of the problems of conventional hypocaloric diet is poor long-term patient adherence. In other words, caloric restriction is difficult for those with type 2 diabetes. People often don’t have the patience to comply with the nutritional adjustment and therefore, often fail to manage their sugar intake. Recently, vegetarian and plant-based diets have been proposed as convenient strategies to encourage the consumption of foods with a lower energy density.

It is important for us to first define these diets and discuss their differences. The vegetarian diet includes the elimination of animal flesh foods, meaning no consumption  of meats or fish. While this diet still consumes eggs  and dairy products, it is primarily based on the consumption of grains, legumes, nuts, fruits, and vegetables. The vegan diet, however, doesn’t include the consumption of any animal products whatsoever, which means vegans can not consume eggs or dairy products.

In randomized trials, compared to conventional dietary guidelines (which includes animal product consumption), vegetarian and low-fat vegan diets have been shown to improve blood lipid concentrations, body weight, and glycemic control. These results have been suspected to occur due to the fact that individuals who follow a plant-based diet consume less calories and fat and instead consume more fiber, potassium, and vitamins. Due to this, more recently, the American Academy of Nutrition and Dietetics as well as the American Diabetes Association have included a well-planned, plant-based diet as a recommendation for individuals with diabetes.

The clinical question this evidence-based case research focused on was: “In patients with type 2 diabetes mellitus, does plant-based diet reduce the HbA1c level compared to conventional diet?” To answer this clinical question, a comprehensive computer-based literature search was conducted on June 20, 2016 using PubMed, Ovid, EBSCO, and the Cochrane Library. Several searches were performed to ensure that all important trials were included. Relevant studies were appraised using critical appraisal worksheets by the Center of Evidence-Based Medicine from the University of Oxford. Twelve studies were found after the comprehensive computer-based literature search using an abstract and title screening process. After the researchers read the full-text versions of the studies, four pieces were removed due to the irrelevance of the topics. Thus, a total of three articles were used in the case report.

The first study by Barnard et al. researched whether a low-fat vegan diet improves glycemic control and cardiovascular risk factors for individuals with type 2 diabetes. In this study, individuals with type 2 diabetes were randomly assigned to either a low-fat vegan diet or a diet that followed the American Diabetes Association guidelines. These individuals were evaluated at the start of the trial and at twenty-two weeks. The vegan diet consumed included fruits, vegetables, grains, and legumes. Participants in this group were asked to not consume animal products, while the control group stuck to the American Diabetes Association diet. Glycemic variables, which included HbA1c were measured. HbA1c was measured in a percentage. HbA1c is the average blood glucose levels for the last two to three months. According to Diabetes UK, an ideal HbA1c level for an individual with diabetes is 48mmol/mol (6.5%) or below. 

The second study was conducted by the same primary authors,  Barnard et al. This study was done three years after the first study, but was done with a longer follow-up period of seventy-four weeks. The focus of this study was the same as the first one and the study design was similar as well.

The third study was a systematic review and meta-analysis by Yokoyama et al. which focused on the associations between vegetarian diets and glycemic control in type 2 diabetes.  In this study, clinical trials were completed where vegetarian or vegan diets were used as interventions for at least four weeks in adults. Changes in HbA1c and fasting blood glucose levels were reported. 

Based on the results of the included studies, it was concluded that in patients with type 2 diabetes mellitus, HbA1c reduction was greater in patients with plant-based diets compared to patients who had a conventional diet. The conclusion states that further research with a larger sample size and an extensive follow-up period is needed to establish a more solid conclusion and to investigate the relationships between specific foods, preferably those which are commonly consumed, and glycemic control. Based on the studies investigated in this report, HbA1c should be examined every three months or each month for individuals with high levels of HbA1c. It was determined that HbA1c is an excellent marker for monitoring type 2 diabetes long-term, but due to the lack of HbA1c examination availability and practicality, more research should be conducted. This report concludes that patients should be advised to continue a plant-based diet with foods that are rich in vegetables, fruits, legumes, and whole grains. Additionally, patients should be informed about portion control in order to ensure that they get appropriate energy intake and nutrients. This evidence-based case report did exactly what it was intended to do. It answered the clinical question asked by using previously conducted studies to draw conclusions. It states that further research should be conducted, which is true, but also does an excellent job of drawing conclusions and data from several other studies already conducted.

In the times we live in now, life is unpredictable. We all desire to live long and healthy lives, but continue to poison our bodies with processed foods, excessive amounts of animal products, alcohol, cigarettes, and drugs. Diabetes continues to claim the lives of more and more Americans every day, whether it be through heart disease, cancer, or obesity. Especially today, there are so many dangerous sources that have the ability to take our lives at any point: Gun violence, car accidents, natural disasters, COVID-19, and so much more. But it’s important, especially now, that we realize that our biggest enemy and most likely killer is ourselves and lack of care for our health. Although our lifespan is determined by genetics and random chance, our healthspan is very dependent on our lifestyle and the way we choose to live. At the end of the day, you are in charge of your health. Although it is difficult sometimes to break the cycle of addiction and self-destruction, every decision you make can either increase or decrease your healthspan. But it’s up to you to make the change. 

As a wise shark once said: “Fish are friends, not food.” This idea reigns true in terms of the consumption of all animal products. Perhaps we should say: “Animal proteins are friends, not food.” Managing diabetes is no rocket science. The solution to living a happier and healthier life is simple: Eat plants. So, you were right Bruce, you were right.


EmmaHook. (n.d.). What is HbA1c? Retrieved from

Type 2 diabetes. (2019, January 09). Retrieved from

Utami, B., & Findyartini, A. (n.d.). Plant-based Diet for HbA1c Reduction in Type 2 Diabetes Mellitus: An Evidence-based Case Report. Retrieved from

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