Appropriate eating patterns and nutritional consumption are two crucial factors for the management of type 2 diabetes (T2DM). These two practices have been associated with the lowering of HbA1c and improving postprandial glycemic excursions, which significantly reduces diabetes-related morbidity and mortality.

Several studies have documented the efficacy of low-carbohydrate or limited-calorie diets in controlling T2DM. In a new American Journal of Medicine Open study, scientists review available publications related to effective behavioral strategies that support patients’ diabetes self-care. The main goal of this review is to provide clinicians with evidence-based dietary guidelines that can be recommended to patients looking to manage their diabetes.

Study: Behavioral Approaches to Nutrition and Eating Patterns for Managing Type 2 Diabetes: A Review. Image Credit: Africa Studio/Shutterstock

Managing T2DM

T2DM can be effectively managed by improving glycemic outcomes. A controlled glycemic measure not only improves the mortality rate associated with T2DM but also decreases the social cost of its morbidity.

Strict adherence to nutritional recommendations, which have been designed against the backdrop of pancreatic beta-cell dysfunction and insulin resistance, can positively control an individual’s glycemic index. 

In the case of insulin resistance, cells exhibit a reduced capacity to use insulin, which leads to a rise in glucose levels. Blood glucose levels also increase when cells are unable to inhibit hepatic glucose production.

During insulin resistance, more insulin is needed to maintain the glucose levels that cause elevated insulin production by pancreatic beta-cells. Gradually, hyperglycemia occurs when the increased insulin production cannot normalize blood glucose levels. An individual with T2DM often loses between 70-80% of beta-cell function.

Nutrition-based interventions for managing T2DM

Two key elements associated with T2DM management are proper nutritional intake and physical activity. Weight loss and/or maintaining balanced macronutrients enables the reduction of glycemic excursions.

Foods with a greater glycemic index or glycemic load are easily digested and increase blood glucose levels and the subsequent demand for insulin. Thus, low-glycemic diets reduce HbA1c levels in individuals with T2DM.

In terms of nutritional impact, one of the major components that enhances postprandial blood glucose levels is carbohydrates. Carbohydrates are digested and broken down into glucose; thus, reduced carbohydrate consumption decreases blood glucose levels.

Less than 35% of daily calories from carbohydrates is considered a low-carbohydrate diet. Currently, a low-carbohydrate diet has replaced a low-fat diet to manage T2DM. Research has shown that very-low-carbohydrate diets can lead to A1c reductions and weight loss for up to six months, but not beyond 12 months.

A high intake of protein improves the insulin response and impacts postprandial glucose excursions. Nutrition-focused interventions based on meal timing, eating patterns, food choices, and nutrient composition can improve overall glycemic control.

Physical activity lowers insulin resistance of tissues and improves responsiveness to insulin, which subsequently decreases the demand for insulin from pancreatic beta cells. Long-term control of T2DM levels reduces the risk of complications and premature death.

Adherence to low-carbohydrate diets was seen to decrease with time, which limited the analysis to only assess the short-term impact of this intervention. Registered Dietitian Nutritionists (RDNs) can support patients to design meals with low glycemic index impact.

Eating patterns and T2DM management

Various eating patterns, particularly the consumption of the Mediterranean diet, have been positively associated with the management of T2DM. A Mediterranean diet is a primarily plant-based eating pattern that involves the increased consumption of legumes, fruits, whole grains, vegetables, olive oil, spices, nuts, fish, cheese, yogurt, and a moderate intake of red wine. This dietary pattern encourages less consumption of red meat, processed food, and refined grains.

A Mediterranean diet is rich in fiber, which reduces post-prandial glycemic excursions. In addition, a higher intake of phytochemicals, particularly polyphenols and antioxidant nutrients, exhibits anti-inflammatory properties.

Several studies have indicated that Mediterranean eating patterns reduce HbA1c levels, delay the need for diabetes medications, reduce insulin resistance, and assist in weight loss over time.

Vegan eating patterns are also associated with glycemic improvements. This dietary pattern reduces HbA1c levels by around 0.4% and improves blood lipid levels in patients with T2DM. Vegetarian eating patterns are associated with high-fiber and low-saturated fat, which not only lowers glycemic index but also reduces LDL cholesterol levels.

The gut microbiome also controls the hosts’ metabolism. Increased gut-derived bacterial toxins and reduced production of bacterial short-chain fatty acids, for example, cause metabolic derangements in T2DM.

A diet rich in fiber and low in animal proteins promotes gut microbial diversity. Moreover, greater protein and fat intake increases bacterial diversity within the gut, including those that increase insulin resistance and T2DM.

Prebiotics and probiotics support healthy gut microbial composition and diversity to ultimately reduce gut permeability and inflammation, subsequently improving insulin sensitivity.

Journal reference:

• Salvia , G. M. & Quatromoni, A. P. (2023) Behavioral Approaches to Nutrition and Eating Patterns for Managing Type 2 Diabetes: A Review. American Journal of Medicine Open. doi:10.1016/j.ajmo.2023.100034