The Right Vegetables for Diabetes and the Ones to Avoid

Nutritionists and doctors extol the virtues of eating more vegetables. Not only are they chock-full of vitamins, minerals and antioxidants, they are also ​rich in fiber, which helps control blood sugar​. This makes them especially beneficial for people with diabetes. With the exception of a few, vegetables are healthy and recommended additions to your diabetes-friendly grocery list.

The carbohydrates in vegetables include sugar, starch and fiber. While sugar and starch affect blood sugar, fiber does not. Fiber — the tough, fibrous part of plant cell walls — is difficult for your body to break down. Because of that, it moves slowly through your digestive tract largely unchanged. It improves digestion as it adds bulk to stool, and it protects against colon cancer. It also helps lower cholesterol by absorbing some of the cholesterol you eat before it can enter your bloodstream.

For everyone, but especially for people with diabetes, fiber plays an important role in blood sugar control. Because it slows the digestion of food, it also ​slows the absorption of sugars into your bloodstream​. Generally, the more fiber a food contains, the less of an effect it has on blood sugar. In addition, when you eat fiber-rich foods with foods that are higher in sugar, the ​fiber can help mitigate the effects of the other foods​.

Most vegetables are also low in calories. Diabetes is often caused by or accompanied by living with overweight or obesity. Maintaining blood sugar control helps people with diabetes manage their disease as well as their weight; eating a diet high in vegetables and lower in more caloric foods can help them reduce their calorie intake for weight loss. ​Reducing body fat and improving body composition is key for improving type 2 diabetes.​

There are ​two types of fiber — soluble and insoluble​: One is soluble in water and the other is not. When soluble fiber dissolves in the fluid in your digestive tract, it forms a gel-like material that can help absorb cholesterol and glucose, carrying it out of your body before it can be absorbed into your bloodstream.

Insoluble fiber does not dissolve; rather, it maintains its shape and helps sweep waste through your digestive system, increasing stool bulk and preventing constipation. Both types of fiber are helpful for overall health and blood sugar control, but ​soluble fiber plays the biggest role in blood sugar control.​

Most plant foods have some soluble fiber. The richest sources of soluble fiber are oats, oat bran, rice bran, barley, citrus fruits, apples and strawberries. Beans, peas and potatoes are also rich sources of soluble fiber. Although these are starchy vegetables, ​people with diabetes can include starchy vegetables in their diets​.

​Read more:​ List of Sugar-Free Foods to Eat for Diabetes

​Starchy vegetables are higher in total carbohydrates and calories​. Unlike fiber, starch is digested into glucose. For these reasons, people with diabetes are advised to control their intake of starchy vegetables, including:

• Potato
  
• Sweet potato
  
• Pumpkin
  
• Acorn squash
  
• Parsnip
  
• Butternut squash
  
• Corn
  
• Peas

The lion's share of vegetables, however, are nonstarchy. This means they contain a negligible amount of starch and are primarily fiber. They are also lower in calories. Because of this, ​people with diabetes can eat nonstarchy vegetables freely​ without worrying. Some examples of nonstarchy vegetables include:

• Daikon
• Eggplant
• Greens (collard, kale, mustard, turnip)
• Hearts of palm
• Jicama
• Kohlrabi
• Beets
• Brussels sprouts
• Broccoli
• Cabbage (green, bok choy, Chinese)
• Carrots
• Cauliflower
• Celery
• Radishes
• Rutabaga
• Salad greens
• Sprouts
• Sugar snap peas
• Swiss chard

To get a better idea of the difference between starchy and nonstarchy vegetables, take a look at a list of some examples in each category with their calorie, carb and fiber counts:

​Starchy:​

• 1 medium baked potato with skin: 164 calories, 37 grams carbs, 4 grams fiber
  
• 1/2 cup boiled, mashed sweet potato: 125 calories, 29 grams carbs, 4.1 grams fiber
  
• 1 medium ear of sweet yellow corn: 99 calories, 21.6 grams carbs, 2.5 grams fiber
  

​Nonstarchy:​

• 2 cups raw spinach: 14 calories, 2.2 grams carbs, 1.3 grams fiber
  
• 1/2 cup chopped carrots: 54 calories, 12.3 grams carbs, 3.6 grams fiber
  
• 1/2 cup chopped celery: 7 calories, 1.5 grams carbs, 0.8 gram fiber

The ​glycemic index (GI)​ is another tool you can use to determine which vegetables to add to your diabetes grocery list. The GI measures how much and how quickly a food raises your blood sugar. ​Foods with lower GI scores can be eaten in greater quantities​ than those with higher GI scores. Foods are categorized as being low- or high-glycemic according to the GI scale:

• Low GI: 1 to 55
  
• Medium GI: 56 to 69
  
• High GI: 70 and above
  

The GI of a food depends on several factors, including:

• Chemical structure
  
• Physical structure
  
• Cooking and preparation methods
  
• Fiber content
  
• Fat and/or acid content
  

Therefore, ​GI is a complex calculation that can only be measured by scientific methods​. However, you can consult a chart to get a reasonable estimate of how a vegetable will affect your blood glucose based on the serving size and cooking method. For example, the GI scores for some starchy and nonstarchy vegetables are:

• Raw carrots: 16
  
• Boiled carrots: 47
  
• Green peas: 39
  
• Cauliflower: 15
  
• Red peppers: 10
  
• Boiled potato: 78
  
• Boiled sweet potato: 63
  

Generally, the more you cook a vegetable, the higher its GI rating because the chemical and physical structure of the food has been altered.

​Ultimately, the question of what you can and can't eat and how much is best answered by your doctor or dietitian.​ Individuals with diabetes have different needs, and their daily carb intakes will vary. It also depends on the quality of the rest of your diet. However, assuming the rest of your diet is healthy, meaning you stay away from processed and refined grains, sugary sweets and sodas, a moderate amount of starchy vegetables — such as potatoes — isn't a problem.

Potatoes and other starchy veggies are rich in nutrients, and their fiber content makes them ​far better for your blood sugar and weight than refined grains and processed foods​ that have little to no fiber or nutrients. If you want to eat a portion of starchy vegetables, make sure it doesn't put you over your daily carb and calorie limits.

Sweet potatoes are the better choice, because they have a lower carb count and GI score. ​Leave the skin on when you make mashed potatoes or bake sweet potato fries.​ The skin contains much of the fiber, which will help regulate the food's effect on your blood sugar.