According to Ayurveda these can be the causes of diabetes or prameha (Type 2):
1. Leading a sedentary life. This means that there is little to no movement in a person's daily life habits and a small amount of exercise practices. During the time when Ayurveda was coming together and practiced people were cultivating land, working outside or had mastered a craft and worked by hand as an artist. I suppose that in some cases there were people who didn't break a sweat doing work and therefore being inactive along with genetic makeup, environmental factors, and poor nutrition supported the progression of prameha.
2. Improper food habits. Food habits are a very important part of wellness in Ayurveda. The word ahara means what we put in and can relate to food or to our experiences. Just like we digest food, we need to digest thoughts, emotions and experiences. A rule of thumb is that the proper food for a person and their energies is taken and the proper amount or quantity of food is taken according to the appetite or agni at the proper time of day. Improper food habits would include eating habitually due to boredom or because food is there, eating when not hungry or overeating. The mind will play a big role in eating. So many of us develop eating habits as children that no longer serve us once we reach adulthood. It is important to be in observation of your own eating habits. How you eat, when you eat, what you eat, with whom you eat with, how fast you eat, do you eat with intention, do you eat rushed, do you eat with gratitude, do you do other things while eating? Breaking old eating habits can take time. The best way is to recognize your patterns and work from there.
3. Excess food intake of sweet, sour and salty tastes with cold quality, oily and heavy qualities. Sweet, sour and salty are the heaviest tastes requiring a high or balanced digestive fire in order to break them down. Out of the 3 tastes sweet will require more agni to digest and the reason for this is that sour and salty have the fire element present whereas sweet taste is cold. Cold, oily and heavy qualities in food will also require more agni or digestive fire to break down.
Let me give you some examples that fall into these categories:
raw foods including uncooked vegetables/salads
cold drinks/iced beverages and refrigerated foods
fried foods in oil
starchy vegetables: potatoes
heavy fruits: banana, grapes, dates, jackfruit, mango
excess candy (modern)
desserts heavy in sugar/milk/carbohydrates
pasta/pizza/ (more modern)
4. Eating meats of domestic, marshy and aquatic animals (these will generally be more kapha or earth and water increasing and sometimes also heating).
5. Eating foods that are consistently increasing to kapha (earth/water), fat tissue and urine.
6. Excess intake of sugar cane products, milk and milk products as all are kapha increasing.
Eating a lot of the foods listed here will weaken your digestive fire- plain and simple. You can even do a lot of exercising but if you eat foods of kapha origin more regularly you will set yourself up for imbalance, potential blocked channels and depletion of ojas or immune health and vitality.