Yes. No. Maybe. It depends on who you ask. But whether or not it is preventable, the trajectory of the disease can be easily influenced by your actions.
Type-2 is a disease process with a genetic basis that requires a trigger. In the simplest possible terms, the underlying disease is your mother’s fault, but when you get it is up to you.
T-2 is triggered by age, weight, or a magic combination of the two. So if you are pre-disposed to get T-2, it will likely manifest when you are either old enough or heavy enough. The age of forty used to be the commonest age. Now that people are getting heavier earlier in life, we notice that the average age at diagnosis is getting younger and younger.
Neither age nor weight alone is enough to cause the diabetes, your body needs to be set up for it. A family history of diabetes is the best indicator of a likely pre-disposition, but lack of a family history of diabetes does not guarantee you are in the clear, as every human is a unique mix of genes from both sides of their family.
As to prevention: for the sake of argument, let’s assume you do have a family history. Frankly, you have a very good chance of getting diabetes. However, the healthier you keep your weight, the older you’ll be before it develops. This is much easier said than done, as the same genes that set you up for diabetes are the also the same ones that make it easy to put weight on and make it hard to keep weight off. Bummer.
So keeping trim is a real challenge for people with Type-2 genes, but making a good effort, and avoiding a lot of empty carbs (such as sodas, excessive sweets, and too many doughnuts and the like) can go a long way to helping push back or prevent the onset of diabetes. And the earlier you start the more likely you will succeed. When your blood sugar starts getting wacky is not the time to start thinking about your diet.
If you have diabetes, or are starting to develop it, your children are at risk too. Even if it is “too late” for you, getting your kids started on life-long healthy eating habits is the single best thing you can do for them.