How much fat is too much fat, especially when it poses a risk for diabetes? Is there a real relationship between obesity and type 2 diabetes, or is this a myth?
Diabetes is a disease marked by high blood glucose, due to defects in insulin production or action, or both. There are type 1 and type 2 diabetes, but type 2 diabetes accounts for about 90 per cent of all diagnosed cases. It typically starts as insulin resistance, where the cells don’t use insulin well. As it progresses and the demand for insulin rises, the pancreas loses its ability to produce insulin
Obesity is a complex, chronic disease that is characterised by an excessive accumulation of adipose tissue to the point that it affects both physical and psychosocial health. It is considered a health crisis globally. The Body Mass Index (BMI) is the most common tool for defining obesity. It measures average body weight against average body height. Generally, a BMI of 35 is associated with obesity.
Obesity has been found to be associated with type 2 diabetes, cardiovascular diseases and fatty liver diseases.
Exploring “diabesity”: Obesity-dependent diabetes
Excess body weight and obesity are significant risk factors for type 2 diabetes. The mechanisms linking both are complex and involve several physiological processes.
The accumulation of an excessive amount of body fat triggers a myriad of metabolic abnormalities and diseases, including insulin resistance, atherogenic dyslipidemia (high plasma triglyceride and low plasma HDL-cholesterol concentrations), nonalcoholic fatty liver disease, β cell dysfunction, prediabetes, and type 2 diabetes. In general, a progressive increase in BMI is associated with a progressive increase in the risk of developing type 2 diabetes.
Excess body fat, particularly visceral fat stored around the abdomen, leads to insulin resistance. Insulin resistance is when the cells become less responsive to insulin, the hormone responsible for regulating blood sugar levels. As a result, glucose builds up in the bloodstream, leading to high blood sugar and, eventually, type 2 diabetes.
The degree of insulin resistance and the incidence of type 2 diabetes is highest in a person with an “apple” shape (abdominal subcutaneous and intra-abdominal fat). These persons carry the majority of their excess body weight around their abdomen. In contrast, the “pear” shaped person carries most of their weight in the hips and thighs (gluteofemoral fat), which is less likely associated with insulin resistance.
The lifetime risk of diabetes in men above 18 years increases from 7 per cent to 70 per cent, when BMI increases from less than 18.5 kg/m to more than 35 kg/m. Same with females, with an increase from 12 per cent to 74% with the same BMI values.
Research has shown that obese individuals are up to 80 times more likely to develop type 2 diabetes than those with a healthy weight. The excess fat tissue in obese individuals secretes various substances, including inflammatory cytokines and free fatty acids, which can interfere with insulin signalling pathways. This creates a vicious cycle where rising insulin resistance leads to elevated blood sugar levels, which promotes further weight gain and inflammation.
Therefore, treating obesity is crucial in the prevention and management of type 2 diabetes; weight loss results in a significant reduction in the incidence of diabetes in at-risk populations.
Conclusion
The relationship between diabetes and obesity is not a myth; both are deeply linked, giving rise to the term “diabesity”. This dual condition poses significant challenges and presents opportunities for healthcare providers to make a profound impact. In next month’s edition, we will explore the role of healthcare providers in turning the tides on diabesity.
References
Yashi K, Daley SF. Obesity and Type 2 Diabetes. [Updated 2023 Jun 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK592412/
Samuel Klein, Amalia Gastaldelli, Hannele Yki-Järvinen, Philipp E. Scherer, Why does obesity cause diabetes?, Cell Metabolism,Volume 34, Issue 1, 2022, Pages 11-20,ISSN 1550-4131,https://doi.org/10.1016/j.cmet.2021.12.012.
