Researchers have found that both proteins in milk, casein and whey, stimulate the production of insulin from the pancreas.

( picture: http://www.swdka.com/upload/201506/12/201506121134298048.jpg )

Elevated Insulin Levels

Milk is very insulinogenic. Even though the glycemic index of dairy products is relatively low, it has a high insulin index. Researchers have found that both proteins in milk, casein and whey, stimulate the production of insulin from the pancreas. In 2001 the study of 3,000 infants with genetically increased risk for developing diabetes was done in Finland. It demonstrated that early introduction of cow’s milk increased susceptibility to type 1 diabetes.

source: http://livingtraditionally.com/read-youll-never-look-milk-way/

(research data)