For individuals managing diabetes, dietary choices play a pivotal role in maintaining healthy blood glucose levels and preventing long-term complications. While conventional wisdom often associates carbohydrates with adverse effects on blood sugar, a nuanced understanding reveals that not all carbs are created equal. This article explores the complex relationship between carbohydrate intake and diabetes management, examining the potential benefits of a high-carbohydrate diet rich in whole, unprocessed plant foods.
Understanding Diabetes and Blood Glucose Control
Diabetes is characterized by elevated blood glucose levels, stemming from either insufficient insulin production (type 1 diabetes) or ineffective insulin utilization (type 2 diabetes). Insulin, a hormone, facilitates the entry of glucose into cells for energy. When insulin is lacking or ineffective, glucose accumulates in the blood, leading to hyperglycemia. Prediabetes signifies blood glucose levels higher than normal but not yet diabetic, increasing the risk of developing type 2 diabetes.
The glucose in your blood comes from certain foods called carbohydrates, or "carbs." Foods that are high in carbs include candy and sweets, sodas, breads, tortillas, and white rice. The more carbs you eat, the higher your blood glucose level will be. Making informed food choices is crucial for individuals with diabetes to maintain healthy blood glucose levels. Effective blood glucose control reduces the risk of serious diabetes-related complications, such as vision loss and heart problems. For those with prediabetes, adopting a blood glucose-friendly diet may prevent the onset of type 2 diabetes.
There isn't a specific diet or meal plan that works for everybody. Your health care provider may have you see a registered dietician (RD) or a diabetes educator who can help design the best eating plan for you. To keep your blood glucose under control, you may need to cut back on certain foods and drinks. This doesn't mean that you can never enjoy them. But you should have them less often or in smaller amounts. If you have diabetes, it's important to eat the right amount of food every day. Eating at the right times is also important. You will want to plan for regular, balanced meals to avoid blood glucose levels that are too high or too low for you. Eating healthy to control your blood glucose does take some effort. But the reward is a chance to live your healthiest life with diabetes.
The High-Carb Paradox: Plant-Based Diets and Diabetes Protection
Contrary to popular belief, a high-carbohydrate diet, specifically one based on whole or minimally processed plant foods, can offer significant protection against type 2 diabetes. People eating high-carb, high-fiber diets enjoy exceptional protection from type 2 diabetes.
Read also: High-Fiber Diet for Better Health
The Adventist Health Study 2 demonstrated that vegans, whose diets are typically high in carbohydrate-rich foods, had half the rate of diabetes compared to non-vegetarians, even after accounting for differences in body weight. It is notable that the non-vegetarians in this study ate red meat and poultry relatively infrequently, suggesting that even small increases in meat consumption disproportionately increase the risk of type 2 diabetes. Other studies from the Adventist group show similar trends. Among 41,387 Adventists followed for two years, vegans had a 62 percent lower risk of developing diabetes compared to omnivores. And among 8,401 Adventists followed for 17 years, eating meat just once a week was linked to a dramatic 74 percent higher risk of diabetes! Both studies adjusted for body weight and other lifestyle variables.
Moreover, in one of the largest studies of plant-based eating patterns to date, people eating a diet emphasizing whole, unprocessed plant foods had a 34 percent lower chance of developing type 2 diabetes in the long term compared with those whose diets were rich in animal products and/or processed foods. However, those eating a plant-based diet high in less-healthy foods such as fruit juices, sweetened beverages, fried potatoes, chips, refined grains, and desserts experienced a 16 percent increased risk of diabetes, highlighting the importance of choosing healthy plant foods.
Insulin Resistance: The Root of the Problem
Insulin resistance is the root problem in prediabetes and type 2 diabetes. In people with insulin resistance, sugar in the blood doesn't enter our cells as easily it should, and the liver produces too much sugar. Over time, this can result in type 2 diabetes. The causes of insulin resistance are complex, but the key players are inflammation, excess dietary fats and calories, unhealthy weight gain, and the buildup of fats inside our muscle and liver cells.
In people with insulin resistance, carbohydrate-rich foods-such as fruit-can cause spikes in blood sugar because sugar can’t enter the cells properly. This leads people to believe that the fruit is somehow at fault, and that they should limit all carbohydrate-rich foods to keep their blood sugar lower. However, avoiding healthy carbs only masks the real issue. A whole-foods, plant-based diet actually treats the underlying cause of insulin resistance because it lowers inflammation, promotes a healthy body weight, and reduces the buildup of fats inside our cells. When we become less insulin resistant, our blood sugar doesn’t go up as high when we eat carbohydrate-rich foods. That is a true test of whether a diet reverses insulin resistance instead of simply treating the symptom of high blood sugar.
Large studies have linked fruit consumption to lower rates of type 2 diabetes, as well as a reduced risk of diabetes complications and premature death in people who already have diabetes. Overall, whole grains (such as oats, barley, brown rice, and whole wheat) are the type of food that is most consistently protective against type 2 diabetes, while processed meat (which contains almost no carbohydrates) increases diabetes risk the most-just one serving per day raises the risk by 37 percent!
Read also: Delicious High-Fiber Smoothie Recipes
Clinical Evidence: High-Carb, Plant-Based Diets for Diabetes Treatment
Randomized clinical trials show that a fully plant-based diet that is high in carbohydrates and fiber and low in fat can lower glycosylated hemoglobin (a measure of average blood sugar), reduce the need for medications, help people lose excess weight, and even lower blood cholesterol more than a conventional diet based on American Diabetes Association guidelines. Notably, plant-based patients in these trials were not asked to measure portions, count carbs, or tally their calories. They just ate healthier foods! A 2014 review of vegetarian diets for the treatment of type 2 diabetes confirmed significant reductions in blood sugar compared to standard diets.
Whole-food, plant-based, high-carbohydrate diets typically exclude nutrients and foods that have been associated with diabetes risk, including animal protein, saturated animal fats, refined grains, and sugar-sweetened beverages. They emphasize unprocessed plant foods, which are naturally rich in fiber, antioxidants, and phytonutrients-substances that reduce inflammation and promote a healthy body weight.
Beyond Blood Sugar: Cardiovascular and Kidney Benefits
Plant-based diets have been shown to prevent and reverse cardiovascular disease, the leading cause of death in those with type 2 diabetes. They also lower blood cholesterol, blood pressure, and inflammation, major risk factors for cardiovascular disease. A growing body of scientific literature shows that plant-based diets may be helpful in delaying the progression of chronic kidney disease, a common complication of diabetes. A plant-based diet may lessen the pain of diabetic neuropathy, a debilitating nerve-related condition in diabetes. Finally, plant-based diets are effective for weight loss, which further improves diabetes control.
Crowding Out Unhealthy Foods
Eating more healthful, carb-rich foods tends to crowd out disease-promoting foods. Added sugars, animal fats, animal protein, and white flour and other refined grains all increase our risk of chronic disease and, in the case of animal protein, even premature death. Animal foods in particular contain higher levels of saturated fat; heme iron; advanced glycation end products; and in the case of processed meats, nitrate and nitrite preservatives. They also stimulate our gut bacteria to make a harmful compound called TMAO. All of these substances promote insulin resistance and other health risks. When you focus on beans, lentils, peas, fruits, vegetables, and whole grains, you not only improve your diabetes or risk of diabetes, but you stack the odds in favor of optimal long-term health.
Mainstream Recognition and Practical Guidance
Mainstream diabetes organizations have recognized the value of a plant-based diet for diabetes. In their 2018 guidelines, the American Association of Clinical Endocrinologists (AACE) recommends a plant-based diet as the preferred eating pattern for patients with type 2 diabetes, and the American Diabetes Association advises that a plant-based diet is a healthful option for patients with type 2 diabetes.
Read also: Explore the pros and cons of a high metabolism diet
If you have diabetes, be sure to work closely with your health care provider if you change your diet, as any medications you are taking may require adjustment. For practical information on how to adopt a plant-based diet for diabetes, check out resources such as the Physicians Committee for Responsible Medicine and Mastering Diabetes.
Navigating the Carbohydrate Landscape: Simple vs. Complex
In recent years, carbohydrates (carbs) have gotten a bad reputation. But carbs can be part of a healthy diet for people with diabetes. It's essential to differentiate between simple and complex carbohydrates. Simple carbohydrates, found in candy, sodas, and refined grains, increase blood sugar quickly and can make it harder to manage your diabetes. Common sources of simple carbs include table sugar, honey, fruit juice, and syrup. These are often major ingredients of highly processed and packaged foods like soda, cookies, cakes, candies, and other foods with added sugars. Some types of simple carbs are found in healthy foods like whole fruit and dairy foods. These foods have beneficial vitamins and minerals, which are key to a balanced diet. Refined grains are simple carbs that have been processed to remove the fiber. This often removes key nutrients as well, some of which are added back in by the manufacturer. Examples include foods like white bread, white rice, white pasta, cereals, pastries, and other desserts. Refined grains are processed to increase shelf life, which can also make them more affordable.
Complex carbohydrates, present in starchy vegetables, legumes, and whole grains, increase your blood sugar more slowly because they contain fiber and other complex starches that take longer for your body to digest. Examples of complex carbs include starchy vegetables (white and sweet potatoes, peas, corn), legumes (beans, lentils), and whole grains. Choose these carbs to get the most nutrition with the least impact on blood sugar. Carbs are an important part of a healthy diet. In fact, your body and brain need carbs to function properly. The key is to choose carbs with fiber and nutrients and to portion your serving sizes. One serving of carbs (15 grams) is smaller than you might think-it's about ¼ cup of granola or 6 saltines!
Practical Tips for Incorporating Healthy Carbs
Carb counting can help make managing blood sugar easier and ensure you're eating a healthy balance of carbs, protein, and vegetables. When you eat a meal or snack with carbs, add a protein source like meat, a small handful of nuts, or low-fat dairy. This will help you stay fuller for longer and avoid blood sugar spikes.
Avoid excessive juice consumption. Ever made orange juice at home? It takes about 3 oranges to get just 1 cup of juice. It’s easy to get too much sugar at once from juice, even when it’s 100% fruit juice. Limit sugar-sweetened beverages like soda, sweetened coffee, and sweetened tea can add a lot of simple carbs to your diet. To reduce added sugars, try mixing half unsweetened tea with half sweet tea, drinking sparkling water with a splash of juice, or ordering coffee with less sweetener.
Choose whole grains wisely. Check the ingredient list. Choose items with whole wheat flour listed as the first ingredient on the packaging-not enriched, unbleached, or multigrain flour. Some breads have seeds and oats on the outside of the loaf or use caramel coloring to make them look like whole wheat. Old-fashioned or steel-cut oats are a great whole grain option instead of sugary cereals. Get creative with overnight oats or baked oat bars to get your day started. Explore grains from around the world, like quinoa, farro, bulgur wheat, barley, and millet. They cook much in the same way as rice and pack a nutritious punch along with extra flavor.
The Glycemic Index and Glycemic Load: A Deeper Dive
Dietary carbohydrate, as the only macronutrient directly digested into glucose, is the main determinant of postprandial glycemia and insulin requirements. For most processed grains and other foods high in glycemic load (GL; the multiplicative product of GI and amount of digestible carbohydrate consumed), the digestion rate is exceptionally fast, increasing immediate insulin demand and exacerbating the aforementioned mismatch between insulin kinetics and glucose appearance. Beyond glycemic control, a high-GL diet may also increase risk for cardiometabolic complications of diabetes, exacerbated by higher associated insulin requirements.
However, independent of amount consumed, qualitative aspects of carbohydrate may influence glycemic control, metabolic responses, and CVD risk factors. Both soluble and insoluble fiber may affect the glycemic response to a meal, the former by increasing intraluminal viscosity in the small intestine and slowing carbohydrate absorption and the latter primarily through mechanical effects that slow digestion of intact foods (e.g., with whole-kernel but not highly refined grains). Dietary fiber may also promote insulin sensitivity through effects on the gut microbiome, production of short-chain fatty acids, and other actions.
Reduced-Carbohydrate Diets: An Alternative Approach
Diets focused on carbohydrate amount can be characterized with reference to prevailing intakes as high-carbohydrate (≥45% EI, “standard”) and reduced-carbohydrate (<45% EI). Reduced-carbohydrate diets can be further categorized as moderate-carbohydrate (MC; 26%-44% EI), low-carbohydrate (LC; 10%-25% EI), very-low-carbohydrate (VLC; <10% EI), and ketogenic. While these definitions are somewhat arbitrary, the term ketogenic refers to a physiologically distinctive state. With restriction of digestible carbohydrate intake to a critical threshold (typically ≤30-50 g/d) and concurrent limitation of protein, the resulting high serum glucagon/insulin ratio increases rates of lipolysis and hepatic ketogenesis, producing concentrations of β-hydroxybutyrate (BOHB) typically between 0.5 and 5.0 mmol/L.
Carbohydrate Reduction in Type 1 Diabetes
The impact of macronutrients on glycemic control in T1D has been extensively studied among populations consuming high-carbohydrate diets. While glycemic control on MC diets was similar to that of the general population with T1D, all LC and VLC studies reported mean HbA1c of less than 7.5%. Moreover, in studies of VLC, HbA1c was in the normal range and insulin doses were low, with the exception of one case report. CGM showed remarkably stable glycemic profiles.
Carbohydrate Reduction in Type 2 Diabetes
Meta-analyses of trials comparing reduced-carbohydrate versus higher-carbohydrate diets or standard of care report modestly lower HbA1c (~0.5%) and reduced usage of glucose-lowering medications, suggesting a clinical benefit greater than that reflected by HbA1c alone. As in studies in T1D, the reduced-carbohydrate diets produced favorable changes in triglycerides and HDL-cholesterol; effects on LDL-cholesterol were inconsistent, with no marked increase seen in any meta-analysis.
Safety Considerations for Carbohydrate-Restricted Diets
Despite more than a century of clinical experience with low-carbohydrate diets, considerable controversy persists regarding the safety of VLC diets for the public in general and people with diabetes in particular .
Hypoglycemia
While hypoglycemia may occur without appropriate insulin dose reduction, a VLC diet may lower the risk for this complication through reduction in prandial insulin requirements, thus ameliorating the difficulty of controlling early postprandial hyperglycemia without causing late postprandial hypoglycemia.
Ketoacidosis
Concern has been expressed that severe ketoacidosis might develop more easily from the baseline nutritional ketosis associated with a VLC diet or that the transition from physiological to pathological ketosis might be hard to recognize. However, the amount of insulin (endogenously secreted or exogenously administered) necessary to maintain normal BG is almost always sufficient to prevent a pathological rise in ketoacids by suppressing excessive lipolysis and ketogenesis.
Cardiovascular Disease Risk
Carbohydrate-reduced diets may increase total and LDL-cholesterol in the general population, mediated in part by higher intake of saturated fats. These elevations have been inconsistently observed in people with T1D or T2D.
Nutritional Insufficiency
Like other restrictive diets, VLC diets have been linked to various nutrient deficiencies. These observations highlight the importance of ensuring proper formulation and professional oversight in prescribing carbohydrate reduction for diabetes. Even with a daily limit of 50 g carbohydrate, a VLC diet can include regular consumption of dairy products, nuts, seeds, non-starchy vegetables, and limited amounts of low-sugar fruits (e.g., berries).
The Fiber Factor: A Key to Unlocking Carbohydrate Benefits
Ten eligible trials including 499 participants with diabetes (98% with T2) were identified from the potentially eligible 828 trials included in existing evidence syntheses. Pooled findings indicate that higher fiber higher carbohydrate diets reduced HbA1c (mean difference [MD] −0.50% [95% confidence interval −0.99 to −0.02]), fasting insulin (MD −0.99 μIU/mL [−1.83 to −0.15]), total cholesterol (MD −0.16 mmol/L [−0.27 to −0.05]) and low‐density lipoprotein cholesterol (MD −0.16 mmol/L (−0.31 to −0.01) when compared with lower carbohydrate lower fiber diets. Trials with larger differences in fiber and carbohydrate intakes between interventions reported greater reductions. Findings indicate the greater importance of promoting dietary fiber intakes, and the relative unimportance of carbohydrate amount in recommendations for people with diabetes.
Comparing Ketogenic and Mediterranean Diets for Type 2 Diabetes
In the new study, conducted from June 2019 to December 2020, Gardner and his team recruited 40 adults with Type 2 diabetes or prediabetes to try both the ketogenic diet and the Mediterranean diet. Half the participants started with the ketogenic diet, and the other half with the Mediterranean diet. After 12 weeks, the groups switched and tried the other diet for 12 weeks. In the ketogenic diet phase, participants followed a version known as the well-formulated ketogenic diet. They were advised to limit carbs to 20-50 grams/day (about 80% less than usual) and proteins to 1.5 grams per kilogram of their ideal body weight per day, and to consume as much as they wanted in fats. Both diets encouraged eating lots of vegetables and eliminating added sugars and refined grains as much as possible.
The researchers found that both diets improved blood glucose control, as indicated by similar drops in HbA1c levels (9% on keto and 7% on Mediterranean). Each diet had one other statistically significant benefit: LDL cholesterol increased on the keto diet and decreased on the Mediterranean diet - a point for Mediterranean. In nutrient levels, the ketogenic diet provided less fiber; thiamin; vitamins B6, C, D and E; and phosphorus. The takeaway, Gardner said, is that there was no additional overall health benefit to cutting out legumes, fruits and whole grains to achieve an ultra-low-carb diet. "Restricting added sugars and refined grains and emphasizing the inclusion of vegetables should be the focus," Gardner said.
tags: #high #carbohydrate #diet #and #diabetes #management