Let us look at the science behind diabetes to answer this question.
We need the energy to live, grow, exercise, and survive. When we eat, in the digestive process, sugar is produced. Sugar finds its way from the digestive system into the blood, where insulin released from the pancreas helps break it down to release energy. This energy then becomes available to the body for its survival and other functions.
Excess sugar not required by us is converted into fats and stored in the liver. This stored fat is broken down into energy and made available when demand exceeds supply.
Insulin plays a blood sugar regulatory role. It prevents blood sugar levels from either rising too high. When blood sugar levels get too high, such a condition is called hyperglycemia. Hypoglycemia, on the other hand, is a low blood sugar condition.
Another reason is that the conversion process itself has become retarded. The cells of the body have become resistant to the available insulin. As a consequence, blood sugar levels rise. The medical name for such a condition is insulin resistance.
There are multiple causes of insulin resistance. Hepatitis C virus infection in the liver is one reported cause. (Petit et al., 2001) The pancreas themselves have become calcified and are unable to produce enough insulin is another reason. (Malka et al., 2000). There are other causes of insulin resistance.
Diabetes manifests itself when insulin produced in the body cannot adequately metabolize the sugar in the blood, causing blood sugar levels to spike.
Multiple risk factors like overweight or obesity, unhealthy diet, physical inactivity, high blood pressure, enhanced cholesterol levels, smoking, gene dysfunction can cause diabetes. Racial factors also have been found to strengthen risk. (Feskens et al., 1989; Choi et al., 2001; Salman. I et al., 2013; Knowler et al.,1990)
There are many causes attributed to the emergence of diabetes. The latest thinking is that an imbalance in the gut microbiota could contribute to diabetes.
We can prevent diabetes by reducing the risk factors that cause the disease to occur.