Diet and diabetes: Here’s what the evidence says

Alistair Gardiner | September 08, 2021

According to a recent CDC report, diabetes is on the rise in young adults, and prediabetes in adults is more prevalent than ever. An estimated 34 million Americans are diabetic and 88 million, roughly one in three, have prediabetes—prompting the CDC to label the situation an epidemic.


Person stepping on scale

The CDC calls diabetes an epidemic, and diet plays a big role. What are the best dietary options for patients with diabetes and prediabetes?

Diet is a major contributor to this condition; 89% of individuals with diabetes are overweight, and 37% have chronic kidney disease. Physicians have myriad dietary options to present to prediabetic and diabetic patients. But what foods and diets are safest and most effective?

From skipping grains to eating more non-starchy veggies, here’s dietary guidance for patients with diabetes or prediabetes, according to studies and health experts.

The big idea behind anti-diabetes diets

According to the Mayo Clinic, a diet-based approach to diabetes management means sticking to regular mealtimes and eating foods that are naturally rich in nutrients and low in fat and calories. The objectives are to control your blood sugar, maintain a healthy weight, and manage heart disease risk factors like hypertension and high cholesterol. 

Consuming excessive calories and fat increases blood glucose levels, which is precisely what patients with diabetes should avoid. Unchecked hyperglycemia can lead to long-term problems like damage to kidneys, heart, or nerves. Most people with diabetes are also overweight, and weight loss can lead to better control over blood glucose levels. Likewise, sticking to regular mealtimes better regulates insulin production.

Foods to eat

Four categories of food can prevent or curb diabetes, according to the Mayo Clinic: healthy carbohydrates, foods packed with fiber, fish, and healthy fats.

Healthy carbohydrates include: 

  • Fruits

  • Vegetables

  • Whole grains

  • Legumes (like peas and beans)

  • Low-fat dairy products. 

Fiber-rich foods include: 

  • Fruits

  • Vegetables

  • Legumes

  • Nuts

  • Whole grains

Fiber refers to the parts of the plant that are indigestible and help moderate the digestion process and regulate blood sugar levels.

Experts advise eating “heart-healthy fish” twice weekly, including mackerel, tuna, salmon, and sardines, all of which are rich in omega-3 fatty acids that can help prevent heart disease.

Finally, nuts, avocado, and canola and olive oils are rich in healthy fats (monounsaturated and polyunsaturated fats). While these foods are high in calories and should be eaten in moderation, such healthy fats can help lower cholesterol. 

According to the NIH, at least half of your daily grain intake should come from whole grains. And experts at the Cleveland Clinic point out that you should also aim to eat more non-starchy vegetables, such as broccoli, cauliflower, carrots, spinach, and tomatoes to control diabetes.

Foods to avoid

Those concerned about diabetes or prediabetes should avoid unhealthy carbohydrates, like foods with added fats, sugars, and sodium.

Also, cut down on foods with saturated fats, like butter, palm and coconut oils, beef, pork products, and processed meats. Avoid trans fats (found in processed snacks, baked goods, and margarine), and cholesterol (found in high-fat animal products like cheese, egg yolks, liver, and others). Aim for no more than 200 mg of cholesterol per day, and no more than 2,300 mg of sodium per day.

According to the NIH, steer clear of treats like candy, ice cream, and drinks with added sugars (including juice, soda, sports drinks, and energy drinks). And, if you’re going to drink alcohol, stick to no more than one to two drinks per day. 

Examples of diets to manage diabetes

There are a number of diets that make it easier to follow the guidelines. Speaking to the Cleveland Clinic, registered dietitian Andrea Dunn listed several that can help most patients with diabetes.

The DASH diet. DASH stands for the Dietary Approach to Stop Hypertension and it's a well-rounded diet that can help those with diabetes. This diet involves consuming limited amounts of fat, sugar, and sodium, and eating plenty of fruits, vegetables, and grains. A typical day might include: six servings of grains, three to four servings of vegetables, four servings of fruit, two-three servings of low-fat dairy, and six or fewer 1-oz servings of lean meats, nuts, seeds, beans, or lentils. 

The Mediterranean diet. There is no strict definition of the Mediterranean diet; rather, it’s based on the eating habits of those living in Italy, Greece, and Southern France. These groups eat lots of vegetables, nuts, and healthy fats, and get the majority of their calories from whole grains, fruits, veggies, beans, and dairy. While you can eat eggs, poultry, and fish a few times a week, you should limit red meats to a few times a month.

A plant-based diet. These diets range from vegan (cutting out animal products) to vegetarian (cutting out meat, but still consuming eggs and dairy), to “flexitarian,” which focuses on plant-based foods, but allows for occasional animal products. 

Other approaches

You don’t necessarily need to stick to a diet like one of those listed above. You can, instead, use The Plate Method: Fill half your plate with non-starchy vegetables, a quarter with lean protein (like fish or chicken), and another quarter with a whole grain (like brown rice). You can also count carbohydrates, which can help regulate your blood sugar levels, because carbohydrates are broken down into glucose.  

Finally, don’t fall for dietary supplements that claim they’ll help manage the disease. There’s simply no evidence that supplementary vitamins, minerals, herbs, or spices will work.

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