If you are like tens of millions of people in North America, chances are that you are something of a Diet Coke addict. You might want a Diet Coke in the morning before you have breakfast, or even drink a DietCoke for breakfast. You will want this bubbly sweet soft drink with meals, and between meals, and before going to bed at night. And if you are a type 2 diabetic, all that diet soda can be doing some very detrimental things to your health. Other diet drinks, which are not as popular, also have this effect, except for a few that are made with stevia.
The problem with diet drinks for people who have type 2 diabetes is that the pancreas also has taste receptors. When you taste something sweet with your tongue, your pancreas gets a copy of the message going to your brain. It releases insulin in preparation for sugars that never come.
The trouble this causes lies in the fact that insulin itself is a major cause of a phenomenon called insulin resistance. When too much insulin comes calling at receptor ports on the outer membranes of cells, they shut down some sites that can receive sugar. They don't shut down sites where insulin transports fat. Drinking diet soda makes your cells less sensitive to sugar and more sensitive to fat.
You aren't going to gain weight if you don't eat too much--but there's another wrinkle in this scenario. When some of the insulin that your body doesn't need to transport sugar arrives at your brain, cells in the brain become more sensitive to sweet taste. So here's what happens:
You drink a sweet drink that isn't really sweet.
Your pancreas makes insulin for sugar that isn't coming.
Cells shut down receptors for sugar transport but leave open receptors for fat transport, so if you have any extra free fatty acids floating through your system they are sure to be stored away.
Your brain likes this kind of sweetness better than regular sugar (when you drink something with real sugar, the insulin is busy storing the sugar, not circulating to your brain). You want to drink more.
The obvous way to handle this problem is to stop drinking Diet Coke and similar diet drinks! There's also some evidence that a chemical called gurmarin, which is in the Ayurvedic herb gurmar, literally, "slayer of sweetness," can stop this process. If you simply can't stop your diet beverage addiction on your own, then taking gurmar may make the diet drinks a little less appealing so you can stop. If you don't stop, you keep fueling the underlying process that made and keeps you a type 2 diabetics.
Selected Reference:
Nakagawa Y, Nagasawa M, Yamada S, Hara A, Mogami H, Nikolaev VO, Lohse MJ, Shigemura N, Ninomiya Y, Kojima I. Sweet taste receptor expressed in pancreatic beta-cells activates the calcium and cyclic AMP signaling systems and stimulates insulin secretion. PLoS One. 2009;4(4):e5106. Epub 2009 Apr 8.