Orange juice contains a high amount of sugar and raises overall blood-glucose levels. It contains a high level of carbohydrates, which is broken down into sugar by the body, according to the National Diabetes Association. This applies to type 2 diabetes, as type 1 is believed to be genetically linked.
When blood sugar increases, the pancreas creates a hormone called insulin, which instructs cells to absorb excess blood sugar. Those with type 2 diabetes often have a resistance to insulin absorption, which causes blood sugar and insulin levels to stay high longer, according to the Harvard School of Public Health. This resistance is conditioned over time due to factors such as poor diet, lack of exercise and too many calories. In this way, drinking orange juice can contribute to causing diabetes in combination with other factors.
In general, orange juice is viewed with suspicion by health professionals because it has a high glycemic load and places high in the glycemic index. These measurements quantify how much blood glucose levels rise after ingesting a food. In moderation, it is believed that drinking orange juice is not a foundational cause for developing diabetes but should be viewed as part of a group of factors including exercise rates and overall diet, states the Harvard School of Public Health.