This Sharepost might be a bit muddled because, according to the latest news buzz, people with diabetes are apt to have "cognitive decline," a polite word for senility. So bear with me if I end up talking about the 1938 World's Fair instead of diabetes. It's not my fault; I have diabetes.

Of course, what these popular press stories don't emphasize is that it's likely high blood glucose (BG) levels rather than a diabetes diagnosis that seem to accelerate aging, including "senior moments" and other signs of brain decline. Although the Time Magazine story does mention "spikes in blood-glucose levels," the assumption is that everyone with diabetes continues to eat the "standard American diet" and hence has spikes in BG levels.

But we know better: that working out an eating plan that controls these spikes contributes to our health and means that all the deleterious things the media is so fond of telling us about are not inevitable.

Nevertheless, diets are not what I wanted to talk about today. Instead I wanted to talk about genes and diabetes.

All types of diabetes have a genetic basis. Some people have the misconception that type 1 diabetes is caused by bad luck in having diabetes genes whereas type 2 is caused by sloth and gluttony. In fact, the genetic connection to type 2 diabetes is even stronger than that to type 1. An identical twin whose twin has type 1 diabetes is less likely to become diabetic than an identical twin whose twin has type 2 diabetes.

And in both cases, a genetic susceptibility is brought on by an environmental trigger. In the case of type 1, that trigger is often a viral infection. In the case of type 2, it's often genetic or environmental factors that contribute to obesity.

An example of a genetic factor causing obesity would be the tiny number of people in the world who lack the hormone leptin. This gives them an insatiable appetite, and small children eat constantly and may weigh more than 100 pounds. One 8-year-old weighed 190 pounds. When you give them leptin injections, their appetite becomes normal and they lose weight. They're not eating because they're unhappy; they're eating because they're ravenously hungry.

Although leptin deficiency is rare, this is a good illustration of the fact that genes can affect appetite, and it's not surprising that people who are constantly hungry will eat more than people who aren't. Those who don't have genetic appetite problems but who have ever had a low-BG episode can imagine what it must be like by remembering that episode, when you wanted to eat everything in sight to get rid of that horrible feeling. The intellectual part of brain knows you should use restraint, but the emotional part of the brain says, "Who cares! I need food and I need it now!" A person with leptin deficiency might feel like that 24/7.

Even if genes don't affect your appetite, they can affect how efficient you are at converting your food to fat. So Frank and Anthony might eat exactly the same things in the same amounts every day, but Frank might be thin and Anthony might be fat.