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Type 2 Diabetes - Root Causes, Implications and Prevention

Updated: Jul 14, 2021

Diabetes is defined by the World Health Organization (WHO) as 'a chronic, metabolic condition characterized by elevated blood glucose levels' [1]. Currently, diabetes affects 422 million adults worldwide, while 193 million patients remain undiagnosed [1]. The classical symptoms of diabetes include frequent urination, excessive thirst, tiredness and weight loss [2]. Diabetes exists in many forms, all of which have dramatic consequences on overall health. The most common one is type 2 diabetes (T2D), which impacts 90% of patients on a global scale [3].

What is type 2 diabetes?

T2D is a chronic disorder characterized by either insulin deficiency or resistance [4]. It has a multifactorial nature associated with both modifiable and non-modifiable risk factors. Non-modifiable risk factors are the ones which cannot be changed (e.g. increasing age, family history and ethnicity), whereas, modifiable risk factors can be improved via lifestyle, behavioral and if necessary pharmacological interventions (e.g. diet and physical activity). T2D has been linked with cardiovascular and mental health disorders [5], and has been named as the sixth cause of disability worldwide [5].

It has been observed, that life expectancy is reduced by seven years for patients with T2D when compared to non-diabetic subjects - mostly due to macrovascular (disease of any large blood vessels in the body, including the coronary arteries, the aorta, and sizable arteries in the brain and limbs) complications [6]. With this in mind, healthcare practitioners have implemented a range of dietary interventions to prevent or delay the progression of diabetes in high risk individuals, which emphasises the importance of dietary changes and physical activity.

Dietary Recommendations

  1. Reduce dietary salt intake - high salt intake has been associated with an increase in blood pressure (hypertension). Given that hypertension is a risk factor to the development of diabetes, individuals are advised to consume a maximum of 6g of salt per day.

  2. Increase consumption of whole grains and fibre - fibre refers to the complex carbohydrates which can neither be digested or absorbed in the small intestine. A recent review evaluating the impact of whole grains and fibre in diabetes prevention and management illustrated that increased consumption of whole grains is associated with significant improvements in glycemic control as well as additional improvements on blood lipids and body weight [7]. Here are some high fibre breakfast ideas:

  • a bowl of wholegrain cereal, blueberries and mixed seeds with milk

  • slice of wholegrain toast with olive oil-based spread with a hardboiled egg

  • a pot of natural unsweetened plain greek yogurt and one portion of fruit with its skin left on

  1. Reduce consumption of processed and red meat - processed meat is defined as 'meat that has been transformed through salting, curing, fermentation, smoking or other processes to enhance flavor or improve preservation' [8]. Individuals are advised to meet the recommendation of a maximum of 70g per day.

  2. Limit alcohol consumption - the recommended alcohol intake is a maximum of 14 units per week. One unit of alcohol is measured as 10ml of a drink e.g. a small glass of wine or half a pint of beer. Alcohol is a source of excess calories as well as free sugars. Frequent alcohol intake can increase blood glucose levels and thus the risk of developing diabetes.

  3. Reduce dietary free sugars - free sugars are defined as 'all monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook or consumer and sugars naturally present in honey, syrups, fruit juice and fruit juice concentrates' [9]. Free sugars provide a substantial amount of calories without any nutrients. which can lead to weight gain - a risk factor for the development of T2D. Considering this, individuals are advised to follow the recommendation of a maximum of 50g free sugars per day.

  4. Increase consumption of oily fish - oily fish is a term used to describe the species which contain oil in their soft tissues such as salmon, tuna and swordfish. Consumption of oily fish has been linked with a lower risk of developing diabetes, hence there is a government recommendation for individuals to meet the recommendation of at least 2 portions per week [10]. If you are vegan, or do not eat fish, it may be necessary for you to consult your GP or a registered nutritionist about taking fish oil (omega 3) supplements.

  5. Increase dietary fruits and vegetables - an increased intake has been associated with a reduction in free sugars and is therefore protective of diabetes. In the UK, practitioners have been promoting the 5 a day rule to encourage individuals consume at least five portions of fruits and vegetables per day. These can be fresh, dried or juiced. Examples of one portion include 1 medium-sized fruit, 150 ml of fruit juice and half a plate of vegetables.

Physical Activity Recommendations

  • 150 minutes of moderate physical activity per week: Moderate physical increases the heart rate, makes breathing faster and makes you feel warmer such as dancing, doubles tennis, pushing a lawn mower, hiking or riding a bike [11].

  • 75 minutes of vigorous physical activity per week. Vigorous activity makes you breathe hard and fast such as running, gymnastics, skipping rope, and martial arts [12].

  • Strength exercise at least 2 days per week e.g. lifting weights/ working with resistance bands/ doing exercises that use your own body weight, such as push-ups and sit-ups.

  • Exercise improves key factors associated with the development of diabetes such as weight, blood pressure, and cholesterol.

Further Support



Written by Pavlina Konstantinou (ANutr & MSc student in Diabetes Care & Management), edited by Abigail Attenborough


  1. World Health Organization (2021) Diabetes, Available at: .

  2. NHS (2018) Type 1 diabetes- Symptoms and getting diagnosed, Available at:

  3. Forouhi N.G. and Wareham N.J. (2014) 'Epidemiology of Diabetes ', Medicine, 42, pp. 698-702.

  4. Chatterjee S., Khunti K. and Davies M.J. (2017) 'Type 2 diabetes', The Lancet, 389, pp. 2239-2251.

  5. GBD (2015) 'Disease and injury incidence and prevalence collaborators. Global, regional and national incidence, prevalence and years lived with disability for 310 diseases and injuries 1990-2015: a systematic analysis for the Global Burden of Disease study', The Lancet, 388, pp. 1545-1602.

  6. Morgan C.L., Currie C.J. and Peters J.R. (2000) 'Relationship between diabetes and mortality: A population study using record linkage', Diabetes Care, 23, pp. 1103-1107.

  7. Reynolds A.N., Akerman A.P. and Mann J. (2020) 'Dietary fibre and whole grains in diabetes management: systematic review and meta-analyses', PLoS Medicine, 17(3), [Online]. Available at:

  8. World Health Organization (2015) Cancer: Carcinogenicity of the consumption of red and processed meat, Available at: file:///C:/Users/Pavlina/Desktop/Presentation/Studies/Cancer_%20Carcinogen icity%20of%20the%20consumption%20of%20red%20meat%20and%20processe d%20meat.html (Accessed: 31st March 2021).

  9. World Health Organization (2021) Reducing free sugars intake in children and adults, Available at:

  10. Guo-Chong C., Rhonda A., Li-Qiang Q., Li-Hua C., Zhendong M., Yan Z., Yang L., Tao W., Thomas E. R. and Qibin Q. (2021) 'Association of Oily and Nonoily

  11. Fish Consumption and Fish Oil Supplements With Incident Type 2 Diabetes: A Large Population-Based Prospective Study', Diabetes Care, 44(3), pp. 672-680. 11. Willett W.C., Sacks F., Tsichopoulou A., Drescher G., Ferro-Luzzi A., Helsing E. and Tsichopoulos D. (1995) 'Mediterranean diet pyramid: a cultural model for healthy eating', American Journal of Clinical Nutrition, 61(6), pp. 1402-1406.

  12. Panagiotakos D., Pitsavos C., Koloverou E., Chrysohoou C. and Stephanidis C.I. (2014) 'Mediterranean diet and diabetes development: a meta-analysis of 12 studies and 140 001 individuals', Journal of the American College of Cardiology, 63(12), pp. 1139-1144.5

  13. NHS (2019E) Exercise, Available at:

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