Expert-reviewed by Ashwini S.Kanade, Registered Dietician and Certified Diabetes Educator with 17 years of experience
Diabetes is a disorder that occurs when your blood sugar is abnormally high. The medical term for this is hyperglycaemia. It occurs when the cells in your body cannot absorb and use the sugar for energy production. The sugar remains in the bloodstream and the amount of sugar in the blood keeps increasing over time, causing the disorder.
Since diabetes worsens persistently as time passes, you may not notice the early signs and symptoms. The disorder may even go undetected for years, especially if you have type 2 diabetes.
However, three main symptoms—excessive thirst, frequent urination, and hunger—are usually seen in people with long-standing type 2 diabetes who have severe hyperglycaemia. 
1. Excessive thirst and frequent urination
More often than not, excessive thirst along with frequent urination is the earliest symptom of both type 1 and type 2 diabetes. You may feel thirsty all the time, and even after drinking water you may feel the dryness of the mouth. This is because the sugar in the blood starts going to the kidneys. Since the urine becomes concentrated with sugar, water from the bloodstream also goes into the kidney to dilute the urine. That’s why you need to urinate frequently. It is termed polyuria.
Therefore, the bloodstream starts lacking water as the sugar concentration increases, and you feel dehydrated and drink more water. Excessive thirst is termed polydipsia.
According to the Association of Physicians of India –
- polyuria constitutes passing at least 2.5 to 3 litres of urine per day,
- polydipsia constitutes drinking more than 6 litres of water per day. 
2. Excessive hunger
Feeling of excessive hunger even after you have eaten, termed polyphagia, is another typical symptom of diabetes. It is different from bingeing and it is not the type of feeling when your stomach is empty.
Hunger from diabetes is because the cells in your body are not absorbing the sugar which is the source of energy for us to live and function. Since the body is starved for fuel, it keeps demanding the fuel in the form of hunger.
Despite these classical symptoms of diabetes, a new study reveals that the three symptoms individually or together do not confirm the presence of diabetes. The researchers found that –
- only 7.34% of people with diabetes in their study exhibited all three symptoms;
- of the study subjects who did not have any of three symptoms, only 84.7% (and not all) probably will not have diabetes, which means, even if you don’t have any of these three symptoms, there is a probability that you may have diabetes. 
Given the fact that diabetes may not have any symptoms in the early stages, it is important to look out for the following warning signs.
3. Unexplained weight loss
If you are not on a weight loss diet or exercising to reduce weight, or on diuretic therapies, but you are losing weight quickly, you may be diagnosed with type 2 diabetes. Researchers from China found that losing 5 kilos or more within 6 months strongly indicated the diagnosis of type 2 diabetes and diabetes complications. 
The reason is, again, high blood sugar. Since the cells cannot use the sugar as energy, they start burning fat and muscle to get the required energy. This causes weight loss. Possible dehydration because of frequent urination also leads to weight loss.
Fatigue is a common complaint if you are suffering from type 2 diabetes, and it is likely to hinder your self-management regimen. Although scientists believed that high blood sugar levels caused the fatigue, later research showed that other contributing factors could be –
- physiological factors such as diabetes complications;
- psychological factors such as stress, emotional distress and depression;
- lifestyle factors such as body mass index (BMI) greater than 25;
- and low physical activity.
In fact, blood sugar levels may have nothing to do with fatigue. 
Scientists generally agree that fluctuations in glucose levels, especially after meals, may also contribute to fatigue. For example, a study found that maximum fatigue was noticed in adults with type 2 diabetes during the first hour after meals. 
5. Velvety dark thickenings (Acanthosis nigricans) on the skin
These velvety thickenings or patches can occur in any part of the body, but they appear mostly on the skin folds. Although the patches can occur across any age group, they seem to decrease with age. The American Diabetes Association has recognised Acanthosis nigricans to be a risk factor for type 2 diabetes in children and adolescents. 
Acanthosis nigricans is a common entity in India. Scientists believe obesity and insulin resistance are responsible for this skin problem. Obesity leads to insulin resistance that causes insulin to accumulate in the blood, which in turn, affects the skin cells.
Apart from the above, the following are also some warning signs of diabetes.
- Fever along with infections, especially urinary tract infection in women and infections of the genital area.
- Burning, tingling, pain and numbness in the feet.
- Itching and irritability.
- Delayed wound healing.
- Impaired vision.
The problem is that the damage to the body starts several years before you notice the symptoms. So, the earlier you become aware of the signs and symptoms, the sooner you can bring the disorder under control and prevent complications, such as kidney disease, heart disease, and blood vessel complications.
- A. Ramachandran. Know the signs and symptoms of diabetes. Indian J Med Res. 2014. Nov; 140(5): 579–581.
- RVSN Sarma. Algorithmic Approach for the Diagnosis of Polyuria. Chapter 69. In: Muruganathan A, editor. Medicine Update. Vol. 23. New Delhi: Jaypee Brothers Medical Publishers (P) Ltd; 2013. pp. 311–3.
- S.D. Pawar, P. Thakur, B.K. Radhe, H. Jadhav, V. Behere, V. Pagar. The accuracy of polyuria, polydipsia, polyphagia, and Indian Diabetes Risk Score in adults screened for diabetes mellitus type-II. Med J DY Patil Univ. 2017.10:263-7 DOI: 10.4103/0975-2870.206569.
- S. Yang, S. Wang, B. Yang, J. Zheng, Y. Cai, Z. Yang. Weight loss before a diagnosis of type 2 diabetes mellitus is a risk factor for diabetes complications. Volti. GL, ed. Medicine. 2016;95(49):e5618. doi:10.1097/MD.0000000000005618.
- C. Fritschi, L. Quinn, E.D. Hacker, S.M. Penckofer, E. Wang, M. Foreman, et al. Fatigue in Women with Type 2 Diabetes. The Diabetes Educator. 2012. 38(5), 662–672. http://doi.org/10.1177/0145721712450925
- S. Bahadursingh, C. Mungalsingh, T. Seemungal, S. Teelucksingh. Acanthosis nigricans in type 2 diabetes: prevalence, correlates and potential as a simple clinical screening tool – a cross-sectional study in the Caribbean. Diabetology & Metabolic Syndrome. 2014. 6:77. doi:10.1186/1758-5996-6-77.