So I was joking with coworkers I was sharing the remains of a birthday cake with that I would’ve gotten diabetes if I’d tried to eat it all by myself. Then I thought of the phrase “tastes like diabetes” to denote “sickeningly sweet,” which made me wonder: we all know the role general weight gain plays in diabetes. But is it actually possible to develop it solely from sugar consumption (and not from the attendant weight gain)? How much would you have to consume?
Sugar makes you fat, and being fat makes you diabetic (with greater probability). But, if you get fat via any other means than sugar, you will still get diabetes (with greater probability). If you eat sugar without getting fat, you won’t get diabetes (generally).
Genetics and weight gain are both contributing factors in diabetes, but not the only ones. Sugar is a simple carb and does pretty much the same thing to the blood glucose. Should you eat X grams of carbs via WonderBread or the same amount of carbs from birthday cake, it would theoretically raise your blood glucose the same.
Perhaps one of the medical dopers can go into greater detail.
First, there are two types of Diabetes Mellitus, in Type-I DM your pancreatic cells do not produce enough (or any) insulin. In Type-II, your bodies cells become resistant to the effects of insulin. When most people talk about getting “Diabetes” they are thinking about Type-II, so that is what I’ll talk about.
One of the major risk factors for Type-II DM is obesity, when a person gains weight, their cells start to become more resistant to the action of insulin (which is responsible for transporting glucose (sugar) from the blood, into the cell). I don’t believe it is possible to develop DM from eating too much sugar by itself, as long as you burn off the calories and don’t gain weight.
Oh, and as missred said, “sugar” is what your body turns any carbohydrate into, be it a bowl of pasta, or pure table sugar.
Not to mention there is also a difference in how diabetics metabolize carbs … because the body is not processing insulin properly.
We can take meds to make us less insulin resistant but the meds get less effective over time. We can take meds to slow down digestion so we have time to better metabolize stuff - but the drugs [specifically byetta] have a heavy nausea effect [i lost the ability to eat several species of meat due to a nausea reaction, and still have trouble 2 years later eating certain pork products without the desire to vomit] and you cant just shove in 10 units of insulin and hork down those red velvet cupcakes.
Really, diabetes sucks - it creeps into the patients whole live, not just shoot up/hork down pills and wander off on your day.
But it is a hell of a lot better now than it was throughout history. Most of the time until the advent of insulin it was a death sentence.
For the record, you don’t even have to be overweight to develop Type 2; the risk definitely goes up if you’re overweight (there’s a theory that fat tissue itself has a role in insulin resistance), but I know several thin, active Type 2s.
Word. I am obese, and I was recently put on insulin after the pills didn’t work well anymore. (About 5 years.)
It’s a big pain to count carbs, check your glucose, determine how much insulin you need. You can’t stop thinking about it for very long. 
And it ain’t cheap!
I wish I had been a better diabetes patient when I was still able to control it just by oral meds. I’m working harder at it now, and I’ve lost 10 pounds! Yay!