"There's very clear evidence that packaged foods are designed to be addictive. Do you know anyone who is addicted to celery?"

He points to the way American cities have grown so large that people are almost required to drive everywhere instead of walking, which means most people aren’t getting anywhere near the right amount of exercise. Jacoby says that 100 years ago the most popular public spaces were parks and plazas—places that encouraged exercise and social interaction. Today, they’re roadways.

I ask Jacoby: Are my friends sick, by chance, because they grew up eating Spaghetti-O’s and Kraft macaroni and cheese like every other kid in the 1980s? Are they victims of an era driven by convenience foods and sugary drinks? (Joe’s father was a Pepsi salesman.)

“Anyone that lives on mac and cheese, a lot of this packaged food, probably will grow up in one way or another addicted to this type of food. It’s well-known that there is very clear evidence that packaged foods are designed to be addictive,” he says. “Do you know anyone who is addicted to chicken or fish or celery? That doesn’t exist.”

While Missy and Joe both possess certain genes that allow them to have these diseases, Jacoby says dependence on processed food as children might have been what brought them to the surface. And it might be the story behind what’s happening to so many Americans.

So, according to this theory, our genes aren’t really changing, but they’re confused. “It’s not going to be an immediate genetic change in society, but what we’re experiencing is that our genes’ expression is being, in a way, modified,” Jacoby says.

It might be that our lifestyle is why Americans are so sick. Another theory, according to Dr. Frederick Miller of the National Institute of Environmental Health Sciences, might be that humans are being weeded out in different ways than in the past, as more communicable diseases have been eliminated.  

“If you do away with the infectious disease risks that perhaps killed off a number of individuals early in life [in the past], people who may have altered immune systems, who perhaps couldn’t have handled [those infections, then] go on in adulthood to develop these diseases,” he says.

He points to the “hygiene hypothesis”: As humans have eliminated infections and led cleaner early lives, allergies and autoimmune disease incidences have increased because of our underdeveloped immune systems. “It’s not completely proven, it’s a hypothesis,” Miller says, “But it is consistent with some of the data out there.”

“There may not be too many free rides in this world,” he says. “As we move away from one disease, we may be moving toward other diseases.”

My husband says he’s lucky. Not because he’s sick, but because it could be so much worse. Joe still holds down a full-time job as a creative director at an advertising agency. He’s still able to play drums in his band.