By: Parco Man, BSc, M.Diet, dietetic student-volunteer, reviewed by Natalie Walsh, RD, and the JM Nutrition Team
As some of our clients have been inquiring about the connection between the low-fat, plant-based diet and type 2 diabetes, we thought we should address the matter herein.
Introduction
Diabetes is a growing global challenge currently affecting over 500 million people worldwide (Saeedi, 2019). While medication and insulin therapy are vital tools, medical nutrition therapy and lifestyle modification have become some of the most effective management strategies. (Jardine, 2023). Most guidelines emphasize carbohydrate management within a healthy, balanced diet. Meanwhile, health professionals are highlighting the specific benefits of a low-fat, plant-based approach.
In this post, we will dive into existing research and guidelines to explore the evidence for low-fat, plant-based nutrition and the viability of this dietary strategy for people living with diabetes.
Before we do, however, let’s take a look at what is type 2 diabetes.
What is type 2 diabetes?
Diabetes refers to a group of diseases characterized by hyperglycemia (high blood sugar) resulting from defects in insulin secretion, insulin action, or both. In type 2 diabetes, the body develops resistance to the effects of insulin and an inadequate compensatory insulin response from the pancreas.
Under normal conditions, when we ingest a meal, our body digests and absorbs nutrients into the bloodstream for transport. Glucose, one of the simplest forms of energy, is rapidly absorbed into our bloodstream for immediate energy fuel or converted into glycogen for storage.
Because maintaining chronically high glucose levels in our bloodstream is harmful, the hormone insulin is responsible for signalling cells to take up glucose. In type 2 diabetes, however, cells do not respond effectively to this signal, leading to ‘insulin resistance’.
As insulin resistance develops, the body’s demand for insulin increases significantly. To compensate and keep blood glucose within a normal range, the pancreas works overtime to secrete even higher levels of the hormone. While this works temporarily, the pancreas cannot sustain this high-intensity production indefinitely.
Over time, this constant “overworking” can lead to the exhaustion of the insulin-producing cells (beta cells). As these cells lose their ability to produce sufficient insulin, the body’s natural regulation system begins to fail, causing blood sugar levels to rise more sharply.
What’s more, type 2 diabetes, a chronic state of high blood glucose, can lead to serious complications. These include cardiovascular disease, retinal complications, kidney damage, nerve damage, foot problems, etc. As a result, active management is essential for long-term health.
Excess body fat and insulin resistance
To truly understand why a low-fat diet is such a compelling topic in diabetes management, we need to explore the hidden relationship between excessive body fat and insulin resistance.
Fat was thought to be a passive storage of energy in our bodies for many years. Modern science, however, has revealed that adipose tissue is a highly active endocrine organ (Keershaw, 2004). When we carry excess body fat, particularly around our organs, these fat cells are not just sitting there. They actively release inflammatory markers into the bloodstream, triggering constant, low-grade inflammation throughout our bodies. This chronic inflammation is known to disrupt the body’s ability to respond to insulin signals and cause problems such as insulin resistance.
Dr. Neal Barnard from Physicians Committee for Responsible Medicine used the ‘key and lock’ metaphor to visualize this process. In a healthy body, insulin acts like a precisely cut key, while receptors on our cells function as locks. When the key turns, the door opens, allowing glucose to enter the cell and be used as fuel. However, excess fat that accumulates within muscle and liver cells can interfere with this process. It acts like sticky residue (imagine gum) inside the lock. Even though the pancreas is producing insulin, the “key” can’t turn effectively, and the mechanism becomes impaired.
Furthermore, this “jammed” system is worsened by the inflammatory markers mentioned earlier, such as C-reactive protein (CRP). These compounds act like roadblocks. They educing the ability of glucose to be delivered to muscles, which are the body’s largest sites for glucose uptake. When muscles are blocked from receiving energy, glucose remains in the bloodstream and contributes to high blood glucose (hyperglycemia) and type 2 diabetes.
These mechanisms provide a direct link between fat accumulation and impaired insulin function. They form the scientific basis for why some health professionals advocate for a low-fat, plant-based diet. The underlying idea is to ‘clear the lock’ by removing excess fat from body cells and improving insulin sensitivity again.
Understanding the biological theory is only one part of the picture. To determine whether this approach is a practical and effective strategy for people living with type 2 diabetes, it is important to examine the available research and how it aligns with current clinical guidelines.
What does the evidence say?
When exploring dietary management for type 2 diabetes, most existing clinical research has focused on established interventions. These include the DASH (Dietary Approaches to Stop Hypertension) diet, the Mediterranean diet, and traditional carbohydrate counting. However, a growing body of research is now focusing on the specific benefits of a low-fat, plant-based approach.
Related: dietitians for plant-based diet support
Several randomized controlled trials (RCTs) have demonstrated that low-fat vegan diets can improve glycemic control, body weight, and cardiovascular risk factors, sometimes showing comparable or slightly greater improvements than conventional diabetes diets (Barnard, 2009, 2006). An RCT conducted in South Korea found that individuals on a brown-rice-based vegan diet saw a hemoglobin A1c (HbA1c) reduction of 0.5%, compared to 0.2% in those following a conventional diet (Lee et al., 2016).
Beyond individual trials, larger reviews and meta-analyses suggest that plant-based eating patterns are consistently associated with modest yet meaningful improvements in insulin sensitivity and blood glucose control. A 2021 review highlighted that vegetarian and plant-based diets reduced HbA1c by approximately 0.3–0.4% more than standard control diets, while also providing benefits for weight management and lipid profiles (Meghan et al., 2021). These findings are further supported by large cohort studies that emphasize the role of whole-food, plant-based nutrition in both the prevention and long-term management of diabetes (McMacken, 2017).
A word of warning
It is important to note that several of these studies originate from the same research group and do not all impose restrictions on the ‘low-fat’ criteria in plant-based diets, although vegan diets usually contain lower saturated fat than animal-based diets. This may highlight the benefits of a broader range of large-scale and high-quality trials to strengthen the evidence base. That said, findings from other populations are emerging.
Recognizing the evidence, major health organizations including the American Diabetes Association (ADA) and Diabetes Canada recognize plant-based diets as a healthy and effective dietary pattern for managing type 2 diabetes. These approaches have been associated with improvements in blood glucose control, cardiovascular risk factors, and overall metabolic health.
We will now take a closer look at the benefits and limitations of the low-fat, plant-based diet in managing type 2 diabetes.
Benefits of the low-fat, plant-based diet in managing type 2 diabetes
It is important to note that there is no single “best” diet that works for everyone living with diabetes. While a plant-based approach is a highly viable and beneficial option, clinical experts usually view it as one of the evidence-based diets alongside Mediterranean, DASH and lower-carbohydrate patterns, which have more evidence to support their effectiveness in managing type 2 diabetes. Meanwhile, the effectiveness of any dietary pattern relies on its alignment with a person’s unique metabolic needs, cultural preferences and ability to maintain the changes over time.
A low-fat, plant-based diet offers several benefits for individuals managing type 2 diabetes. This is particularly true when it focuses on whole, minimally processed foods and low-glycemic carbohydrates. The benefits are as follows:
Supports weight management
Weight management support is one benefit.
Plant-based foods generally have a lower energy density, meaning they provide fewer calories for their volume (Ivanova, 2021). This allows individuals to eat satisfying portions while naturally reducing overall calorie intake, often leading to gradual and sustainable weight loss. This can be beneficial to overweight or obese individuals. Reason being, reducing excessive body fat is an important factor in improving insulin sensitivity.
Related: dietitians for weight loss support
High in dietary fibre
Increased intake of fibre is another benefit of a low-fat, plant-based diet.
Foods such as legumes, whole grains, fruits and vegetables are rich in fibre. They have been consistently shown to benefit blood glucose control and weight management (Nitzke, 2024). Fibre slows down carbohydrate absorption. This prevents sharp spikes in blood sugar. Meanwhile, it can also promote satiety and support digestive health.
Reduces LDL cholesterol level and supports heart health
Additionally, low-fat, plant-based diets are typically lower in saturated fat and cholesterol. This can help reduce LDL cholesterol levels. Research shows that vegetarian and vegan diets consistently lower blood cholesterol and lipids (Koch,2023). While this can improve insulin sensitivity, it also helps manage one of the complications related to type 2 diabetes, cardiovascular disease.
Moreover, the high intake of potassium-rich plant foods may contribute to better blood pressure control, which is an important consideration for individuals with diabetes who are at increased cardiovascular risk (Filippini, 2020).
Rich in antioxidants and anti-inflammatory compounds
Another benefit of a low-fat, plant-based diets is the abundance of antioxidants and anti-inflammatory compounds.
Plant-based diets provide a wide range of antioxidants and phytochemicals, such as flavonoids, that help reduce oxidative stress and chronic inflammation. These processes are closely linked to insulin resistance. As such, reducing them may help improve insulin sensitivity and reduce damage to cell DNA.
Let’s now touch upon the limitations of the low-fat, plant-based diet in managing type 2 diabetes.
Limitations of the low-fat, plant-based diet in managing type 2 diabetes
Despite its potential benefits, a low-fat, plant-based diet also comes with several important limitations that should be carefully considered:
Risk of nutrient deficiencies
Nutrients such as vitamin B12, iron and vitamin D may be lacking or less bioavailable in plant-based diets. Without careful planning, this can increase the risk of deficiency, making supplementation or fortified foods necessary for some individuals.
Protein and calcium adequacy
Meeting protein needs on a plant-based diet is achievable but requires a varied intake of protein sources to ensure adequate essential amino acids. Similarly, calcium intake may be insufficient if dairy products are removed without including appropriate alternatives such as fortified plant-based beverages or calcium-rich plant foods like leafy greens, tofu and nuts.
In addition, individuals with pre-existing nutrient deficiencies (such as B12, iron or vitamin D), people who are underweight, or those with increased nutritional needs, such as pregnant or lactating women, infants, older adults and individuals with a history of eating disorders, should consult a healthcare professional before making significant dietary changes.
Final Thoughts: Low-fat, plant-based diet in managing type 2 diabetes
In summary, a low-fat, plant-based diet presents an evidence-supported approach for managing type 2 diabetes. This is particularly true through its effects on weight management, high fibre content, and potential anti-inflammatory effects.
It is also important to acknowledge that there is no one-size-fits-all solution. While some individuals may experience significant improvements, others may find alternative dietary patterns more suitable for their lifestyle and long-term adherence.
Likewise, it is important to remember that you do not necessarily have to go “all or nothing” overnight. Many people find success by starting with one plant-based day per week or simply swapping one daily meal for a plant-based option to see how their body and their blood sugar respond.
In addition, if you are interested in trying out a low-fat, plant-based diet to manage your type 2 diabetes, remember to discuss it with your physician or dietitian to ensure nutritional adequacy and get help with planning.
Last, here are some meal plans and recipes from the American Diabetes Association, Diabetes Canada and Physicians Committee for Responsible Medicine for reference.
American Diabetes Association: https://diabetesfoodhub.org/recipes/vegan-vegetarian
Diabetes Canada: https://www.diabetes.ca/nutrition-fitness/meal-planning/7-day-vegan-healthy-meal-plan
Physicians Committee for Responsible Medicine: https://www.pcrm.org/health-topics/diabetes
Conclusion
Should you feel you require personalized sessions for guidance of a dietitian pertaining to diabetes and/or the plant-based diet, book a free consultation or contact us for an appointment. As always if you have comments or questions, we encourage you to let us know.
References
1. Lee YM, Kim SA, Lee IK, et al. Effect of a brown rice based vegan diet and conventional diabetic diet on glycemic control of patients with type 2 diabetes: a 12-week randomized clinical trial
2. McMacken, M., & Shah, S. (2017). A plant-based diet for the prevention and treatment of type 2 diabetes. Journal of geriatric cardiology : JGC, 14(5), 342–354. https://doi.org/10.11909/j.issn.1671-5411.2017.05.009
3. Jardine, M. A., Kahleova, H., Levin, S. M., Ali, Z., Trapp, C. B., & Barnard, N. D. (2021). Perspective: Plant-Based Eating Pattern for Type 2 Diabetes Prevention and Treatment: Efficacy, Mechanisms, and Practical Considerations. Advances in nutrition (Bethesda, Md.), 12(6), 2045–2055. https://doi.org/10.1093/advances/nmab063
4. Barnard, N. D., Cohen, J., Jenkins, D. J., Turner-McGrievy, G., Gloede, L., Green, A., & Ferdowsian, H. (2009). A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. The American journal of clinical nutrition, 89(5), 1588S–1596S. https://doi.org/10.3945/ajcn.2009.26736H
5. Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Jaster B, Seidl K, Green AA, Talpers S. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care. 2006 Aug;29(8):1777-83. doi: 10.2337/dc06-0606. PMID: 16873779.
6. Saeedi P, Petersohn I, Salpea P, Malanda B, Karuranga S, Unwin N, Colagiuri S, Guariguata L, Motala AA, Ogurtsova Ket al. Global and regional diabetes prevalence estimates for 2019 and projections for 2030 and 2045: results from the International Diabetes Federation Diabetes Atlas, 9th edition. Diabetes Res Clin Pract. 2019;157:107843
7. Kershaw EE, Flier JS. Adipose tissue as an endocrine organ. J Clin Endocrinol Metab. 2004 Jun;89(6):2548-56. doi: 10.1210/jc.2004-0395. PMID: 15181022.
8. Ivanova, S., Delattre, C., Karcheva-Bahchevanska, D., Benbasat, N., Nalbantova, V., & Ivanov, K. (2021). Plant-Based Diet as a Strategy for Weight Control. Foods (Basel, Switzerland), 10(12), 3052. https://doi.org/10.3390/foods10123052
9. Nitzke, D., Czermainski, J., Rosa, C., Coghetto, C., Fernandes, S. A., & Carteri, R. B. (2024). Increasing dietary fiber intake for type 2 diabetes mellitus management: A systematic review. World journal of diabetes, 15(5), 1001–1010. https://doi.org/10.4239/wjd.v15.i5.1001
10. Koch, C. A., Kjeldsen, E. W., & Frikke-Schmidt, R. (2023). Vegetarian or vegan diets and blood lipids: a meta-analysis of randomized trials. European heart journal, 44(28), 2609–2622. https://doi.org/10.1093/eurheartj/ehad211
11. Filippini, T., Naska, A., Kasdagli, M. I., Torres, D., Lopes, C., Carvalho, C., Moreira, P., Malavolti, M., Orsini, N., Whelton, P. K., & Vinceti, M. (2020). Potassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials. Journal of the American Heart Association, 9(12), e015719. https://doi.org/10.1161/JAHA.119.015719
12. Meg G. Salvia, Paula A. Quatromoni (2023) Behavioral approaches to nutrition and eating patterns for managing type 2 diabetes: A review
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About Author:
Natalie is a Toronto-based dietitian who who focuses her practice on weight management counselling, menopause support of a dietitian, digestive health, hearth health and more. Natalie is registered with the College of Dietitians of Ontario.
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