Type 2 diabetes: Nutrition

The diet for type 2 diabetes should always be balanced and varied and preferably includes nutrient-rich, low-processed foods with high levels of fiber. In contrast, high-energy foods with added sugars and saturated fats as well as white flour products such as white bread, white rice and white pasta should be avoided as far as possible.

Based on current knowledge, no definitive form of nutrition can be recommended for people with diabetes. Instead, various forms of nutrition have a positive effect on sugar metabolism, blood lipids and the risk of complications. For example,

• a plant-based (vegetarian and vegan) diet,
• the so-called Mediterranean-style diet,
• a low-carbohydrate diet and
• a protein-rich diet

represent possible options for people with type 2 diabetes.

So far, it has not been clearly established whether a certain type of diet is particularly suitable for people with type 2 diabetes in the long term. This is why personalized nutritional advice isrecommended for people with type 2 diabetes. Within this framework, a nutritional concept – adapted to the diabetes therapy as well as personal preferences and everyday circumstances – can be defined. What is important in this context is that the concept can be implemented individually in everyday life.

The German Diabetes Association (DDG) advises people with type 2 diabetes to focus on the commonalities of dietary patterns that have a positive effect on type 2 diabetes management. On the one hand, this means giving preference to vegetables with a high fiber and low starch content as well as less processed foods. In addition, added sugars and highly processed cereal products should be reduced or even avoided.

The composition of nutrients and the properties of food also play a decisive role in type 2 diabetes management. The following must be taken into account:

• The composition of the fat content (as much unsaturated fatty acids as possible, for example from rapeseed oil, oily sea fish, nuts and linseed and little saturated fatty acids, for example from sausage products)
• The content of fiber
• The effect of carbohydrate-containing foods on blood sugar levels

Researchers have proposed a new classification into a total of five diabetes subtypes. The subtypes are intended to make it possible to map and treat the complexity and individual progression of diabetes mellitus more accurately. The subtypes differ in terms of:

• The origin of the disease
• The course of the disease
• The risk of diabetes-related complications

To date, the data available on the nutrition in relation to diabetes subtypes is very limited. It is therefore not yet possible to derive specific dietary recommendations for the individual subtypes. This underlines the importance of individualized nutritional therapy in order to exploit the full potential of the basic therapy.

Carbohydrates, alongside fat and protein, are crucial energy sources for the human body. All carbohydrates are made up of sugar building blocks: some contain only 1 or 2 sugar building blocks (e.g., glucose or household sugar), whereas others are made up of long chains of sugar building blocks (for example starch). The body transforms the consumed carbohydrates into glucose (1 sugar building block) to generate energy.

A low-carb diet can contribute to an improvement in sugar metabolism and weight loss. Depending on the definition, a moderate low-carb diet is characterized by a content of 26 to 45 percent carbohydrates in total energy intake. A diet with fewer carbohydrates can be implemented through various dietary patterns, for example a Mediterranean-style diet.

People with type 2 diabetes should preferably take in carbohydrates from

• wholewheat products with a high content of whole grains;
• vegetables with a low starch content, such as leafy vegetables, cabbage, peppers, zucchinis, tomatoes, cucumbers and asparagus;
• legumes such as beans, peas, lentils, soy and soybeans; and
• low-sugar fruit, for example apples, pears, berries, citrus fruits and melon.

Among other things, these foods contain a lot of fiber which means that blood sugar rises more slowly. A daily intake of at least 30 grams of fiber is recommended. This corresponds, for example, to 5 portions of vegetables and fruit, at least 1 portion of pulses per week and 2 to 3 slices of wholewheat bread.

On the other hand, people with diabetes should eat the following foods in small quantities or avoid them:

• White flour products such as white bread/rolls, white pasta and white rice
• Products with free sugars, for example sweets, pastries, desserts, sweetened drinks
• Fast food and convenience products with a high content of saturated fatty acids such as frozen pizza, canned ready meals, French fries and potato chips
• Processed sausage products

These foods cause blood sugar levels to rise quickly. Specialist associations recommend no more than 50 grams of free sugars per day (less than 10 percent of total energy intake). This corresponds to about 12 teaspoons per day. Free sugar refers to all sugars added to foods and drinks and sugar naturally contained in honey, syrup, fruit juices, and fruit juice concentrates. Sugar-sweetened drinks should be avoided as far as possible and replaced with water or unsweetened tea.

Note: Processed foods often contain a lot of sugar, even though they taste salty.

People with type 2 diabetes should also consume starchy vegetables such as potatoes and corn as well as fruit (fruit products) in moderation. Pay attention to portion sizes and preparation.

The glycemic index (GI) illustrates the effect of foods containing carbohydrates on the blood sugar level. It predicts how fast and how much the blood sugar will increase after eating a certain type of food.

The 100% reference value is the blood sugar level after the intake of 50 grams of dextrose. When comparing to other foods, the exact amount of the respective food that also contains 50 grams of carbohydrates is used. For example, that would be 100 grams of lentils or 60 grams of cornflakes. Foods containing carbohydrates that have a high GI (e.g., white bread, cornflakes, or French fries) cause a large and rapid increase in blood sugar levels. In contrast, foods containing carbohydrates that have a low GI (e.g., pulses, vegetables, and wholewheat products) enter the bloodstream more slowly, resulting in a more moderate increase in blood sugar levels.

To estimate the effects of a food containing carbohydrates on the blood sugar level in relation to the amount of carbohydrates consumed, the glycemic load (GL) is also often calculated. GL provides an indication of the blood sugar response to a portion of a food containing carbohydrates. The GL is the product of the GI and the net carbohydrates (in grams) per food portion divided by 100.

Being overweight or obese promotes the the onset of type 2 diabetes. In many studies, scientists have shown that overweight people with type 2 diabetes were able to notably improve their blood sugar values by losing weight.

Furthermore, being overweight or obese – alongside type 2 diabetes – can cause a wide range of complications that severely impair quality of life. These include, for example fat metabolic disorders, high blood pressure, cardiovascular diseases, tumor, kidney and lung diseases as well as mental illness. Weight loss can prevent the onset of these complications and improve quality of life.

The appropriate weight loss should be determined individually as part of nutritional counseling. When losing weight – especially in older people with type 2 diabetes – care should be taken to minimize the loss of muscle mass.

After losing weight, it is important to maintain the weight in the long term. In addition to diet, regular physical activity (even of low intensity) and a lasting change in behavior play a decisive role. Both the strategy for weight loss and subsequent weight maintenance should be based on individual preferences and feasibility.

Replacing meals with so-called formula diets with a low calorie content can be used as an initial measure to achieve a reduced calorie intake and thus promote weight loss. However, it is crucial that these successes and further weight loss are maintained through a long-term change in diet. Various options are available for long-term weight loss and stabilization of body weight:

• A moderate low-carb diet in which the intake of simple carbohydrates such as sugar and refined carbohydrates is reduced.
• A plant-based diet in the form of a Mediterranean-style or vegetarian diet, in which the intake of animal products is reduced and plant-based foods such as wholewheat products, vegetables, fruit, pulses, nuts and healthy fats are consumed more often.
• Intermittent fasting can also help you lose weight if you have a negative energy balance. Due to the increased risk of low blood sugar levels, medical supervision is required.
• Both low-carb and low-fat diets are effective in maintaining weight in the long term. The choice between them should be made individually, based on personal preferences and health goals.

According to current knowledge, no diet is clearly superior in terms of weight loss. Whether a diet to achieve weight loss is successful in the long term often depends on compliance, personal preference and compatibility with one’s daily routine. It is therefore important to choose a diet that is sustainable for the individual and can be integrated into everyday life.

Find out more about overweight and obesity and the treatment options here!