My Dad has Type 2....
The cause of Diabetes is unknown.
The on-set of the disease is associated with a poor diet (too rich in saturated fats and carbs, especially sugar), obesity, inactivity and age. These are factors ASSOCIATED with the on-set of the disease, but none is know to be the CAUSE of it.
My own father got it when he was in college. He was very slender and was on the crew team (rowing) - perhaps THE most physical of all competitive sports - not an ounce of fat on him, and he had to keep himself as light as possible sicne every ounce counts in the boat. VERY trim, VERY fit. And he ate no sweets, no desserts, no booze EVER. And he was like 20. NONE of the things associated with Type 2 applied to him. But here's the deal - his father died from complications of diabetes when dad was in high school.... all his uncles died from complications of diabetes, all his brothers got diabetes..... There is an OBVIOUS genetic link.... but again, no one knows the CAUSE of it. My Dad is among the many, many with Diabetes who make a LIE out of the common misconception that diabetes is punishment for being fat, lazy and eating like a pig.
My brother is 32 and was just diagnosed with it. He is 6-2, weighs 175 and works out 50 minutes every single morning.
Those with it usually better MANAGE it via diet, exercise.... it's possible via diet and exercise alone to keep the numbers below a 6.0 AIC and thus totally controled, but they still have the disease, they just have it controlled. Diabetes is progressive, so the longer one has it, the worse the disease gets - and typically at some point, medication is needed.
There is no known cause... there is no known cure. There are things ASSOCIATED with it's onset and things associated with it's management.... but the cause and cure are unknown.
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