Weight reduction as a non-pharmacological treatment method for type 2 diabetes

INTRODUCTION

Type 2 diabetes is one of the most common chronic metabolic disorders encountered in the daily practice of family physicians. It is characterised by insulin resistance and a relative insulin deficiency, leading to hyperglycaemia. Persis-tent hyperglycaemia over time results in numerous complications, including cardiovascular diseases, neuropathy, nephropathy, and retinopathy. Effective management of diabetes relies not only on implementing pharmacotherapy but also, and primarily, on modifying dietary habits, incorporating regular physical activity, ceasing alcohol consumption and smoking, and most importantly, achieving weight reduction.
The aim of this paper is to evaluate the impact of excessive weight reduction as a non-pharmacological approach to treating type 2 diabetes. It analyses and describes how excess body weight affects the body’s carbohydrate metabolism and highlights the importance of weight reduction and dietary habit changes in the treatment process.

EPIDEMIOLOGY

The epidemiology of type 2 diabetes is closely linked to risk factors such as a high body mass index (BMI), decreasing physical activity, an aging population, genetic predisposition, and unhealthy dietary patterns, including high consumption of simple sugars and saturated fats. Currently, type 2 diabetes is a global health challenge, affecting millions of new individuals annually. According to data from the International Diabetes Federation (IDF), in 2021, the number of people with diabetes was approximately 537 million, the majority of whom had type 2 diabetes. The federation predicts this number will rise to 783 million cases by 2045 [1]. The prevalence of type 2 diabetes varies across continents, with the highest rates observed in regions with high levels of urbanisation and industrialisation, such as North America, Europe, and certain countries in the Middle East and Southeast Asia (Table 1). In developing countries, especially in Africa, the number of cases is increasing significantly, driven by lifestyle changes and urbanisation [2]. In Poland, the prevalence of diabetes has been increasing in recent decades (Fig. 1). In 2021, the number of people with diabetes was ap-proximately 2.7 million, representing 6.8% of the adult population. According to IDF estimates, this figure is expected to rise to about 3 million by 2030. A significant portion of patients in Poland remains undiagnosed, particularly those with type 2 diabetes; it is estimated that in 2021, this applied to approximately 1.8 million individuals [3].

THE RELATIONSHIP BETWEEN EXCESS BODY WEIGHT AND TYPE 2 DIABETES

Excess adipose tissue is one of the most significant diabetogenic factors [4]. Adipose tissue, particularly visceral fat, actively participates in metabolic processes by increasing the secretion of adipokines such as leptin, resistin, and visfatin, while reducing the secretion of adiponectin, which significantly impacts the body’s carbohydrate metabolism (Fig. 2). Leptin, resistin, and visfatin decrease glucose uptake by muscles, reduce insulin production by affecting pancreatic β cells, and increase lipolysis, ultimately leading to reduced insulin sensitivity and a compensatory increase in insulin secretion by β cells, which, over time, may result in the depletion of their reserves [5]. Moreover, excess adipose tissue induces a low-grade chronic inflammatory state, characterised by overactivation of macrophages that secrete pro-inflammatory cytokines. These cytokines inhibit insulin signalling in cells and directly impair the function of insulin receptors [6]. Excess adipose tissue also stimulates the overproduction of free fatty acids by adipocytes, which increases gluconeogenesis in the liver (conversion of non-carbohydrate precursors into glucose) and enhances fat oxidation in muscle cells at the expense of reduced glycolysis (glucose metabolism) (Fig. 3) [7]. Visceral adipose tissue excess con-tributes to mitochondrial dysfunction, which reduces the ability of cells to oxidise fatty acids and leads to lipid accumulation in peripheral tissues, further exacerbating insulin resistance [5].

THE IMPACT OF WEIGHT REDUCTION ON TYPE 2 DIABETES

INCREASED INSULIN SENSITIVITY

Weight reduction, particularly of visceral fat tissue, leads to a decrease in insulin resistance. This is associated with a reduction in inflammation, a decrease in the secretion of adipokines by adipocytes, and an overall improvement in the function of insulin receptors in skeletal muscles, the liver, and adipose tissue [5].

IMPACT ON PANCREATIC β-CELL FUNCTION

Weight reduction, and consequently the reduction of visceral fat tissue, significantly alleviates the burden on pancreatic β cells by lowering the body’s demand for insulin. This process helps preserve the functional reserves of β cells and may delay disease progression [4, 5].

REGULATION OF LIPID METABOLISM

Weight loss and dietary habit changes are associated with reductions in triglycerides (TG), total cholesterol, and low-density lipoprotein (LDL) cholesterol levels. These factors are crucial in reducing cardiovascular risk, which is often linked to type 2 diabetes. Additionally, weight loss decreases gluconeogenesis and fatty acid oxidation while enhancing glycolysis in skeletal muscles [5].

WEIGHT REDUCTION IN THE TREATMENT OF TYPE 2 DIABETES

Nutritional therapy, including dietary changes, should be implemented for every patient with type 2 diabetes and serves as the cornerstone of weight reduction. Effective nutritional therapy should include educating patients about the regular consumption of an appropriate number of meals and the correct caloric intake based on calculated individual needs. Studies show that a weight loss of more than 5% results in noticeable improvements in diabetes control, while a reduction of more than 7% of initial body weight may lead to the resolution of prediabetes. Losing more than 10% of body weight in patients with early-stage type 2 diabetes can result in disease remission. Another essential lifestyle modification for all type 2 diabetes patients is regular physical activity, undertaken at least 2-3 times per week, ideally daily. The goal of daily physical exercise is to reduce body weight and increase the insulin sensitivity of the body’s cells [8]. As an alternative – not a substitute – for dietary therapy and physical activity, bariatric surgeries, such as gastric bypass or sleeve gastrectomy, are recommended for patients with type 2 diabetes and a BMI > 35 kg/m². These procedures are effective methods for achieving lasting weight loss and improving diabetes outcomes [9].

CLINICAL EFFECTS OF WEIGHT REDUCTION

Numerous clinical studies have demonstrated that weight reduction provides significant therapeutic benefits for patients with type 2 diabetes. A weight loss of 5-10% reduces the need for glucose-lowering medications, improves lipid profiles and blood pressure, and leads to a decrease in HbA1c levels [10]. Additionally, substantial weight loss exceeding 15 kg has been shown to induce remission of type 2 diabetes in some patients [11].

LIMITATIONS AND CHALLENGES

Although weight reduction has highly beneficial effects on the management of type 2 diabetes, maintaining these outcomes over the long term can be challenging and depends on the individual approach of each patient. Moreover, patients may exhibit varying degrees of response to interventions due to factors such as genetics, metabolism, age, and comorbid conditions, which significantly influence their effectiveness. Additionally, the workload of healthcare professionals often makes it difficult to thoroughly explain the importance of weight reduction and the critical role the patient plays in the treatment process. Finally, patient willingness to cooperate and adhere to recommendations is a common challenge, particularly regarding changes in dietary habits, implementing regular physical activity, or abandoning un-healthy behaviours such as smoking and alcohol consumption.

CONCLUSIONS

Weight reduction is a fundamental component of the non-pharmacological treatment of type 2 diabetes. It enhances insulin sensitivity, reduces the burden on pancreatic  cells, improves their function, and lowers the risk of cardiovascular complications and chronic inflammation. The key to success lies in an individualised therapeutic approach that com-bines diet, physical activity, and psychological support. Long-term success depends on sustainable lifestyle changes and access to multidisciplinary medical interventions.

Disclosures

This research received no external funding.
Institutional review board statement: Not applicable.
The authors declare no conflict of interest.

References