At a baby shower for a co-worker, Patti Smith reached for a cookie and was scolded by an officemate.

“People watch what you eat,” says Smith, 56, who lives in El Cajon, Calif., and was diagnosed with Type 2 diabetes three years ago. She manages the disease through a strict diet — one cup of oatmeal for breakfast, a salad for lunch, kale chips for a snack, leftover salad for dinner after she finishes work and before she hits the gym. She weighs every portion and counts every carb. When she dines at a restaurant, she packs up half her meal to go before she even starts eating. She has lost 90 pounds and keeps her blood glucose levels in check without medication. “I know where I’m at,” she says. “If I want to treat myself with a cookie once a month, I can have a cookie.”

Diabetes: A Special Report

It’s a frustrating reality for people with Type 2 diabetes — they often receive more criticism than understanding, and they’re treated as though their incurable condition is essentially self-inflicted.

“Part of what makes diabetes hard to accept for those who have it is that we talk about it negatively,” says Susan Guzman, a clinical psychologist who specializes in diabetes care and co-founded the Behavioral Diabetes Institute in San Diego. “It has two forbidden sins: gluttony and sloth.”

There are understandable reasons behind this perception: More than half the people with Type 2 diabetes are obese, and diet and exercise are well known to be important tools for managing the condition.

But obesity is not the only contributing factor. A constellation of genetics, race, age and environmental factors such as influences in the womb also affect whether a person develops the disease, and none of them can be controlled.

Even obesity is a tricky issue. “Many people think obesity is a lifestyle disorder,” says Sethu Reddy, chief of the adult diabetes section at Joslin Diabetes Center in Boston. “But there are a whole host of biochemical changes that might lead to obesity.”

Nevertheless, the blame persists, says Jessica Browne, a researcher at the Australian Center for Behavioral Research in Diabetes in Melbourne.

“There are a lot of different factors that go beyond the individual behavior and the individual responsibility,” says Browne, who led a study of Type 2 patients that found that a large majority feel judged or blamed for having the disease.

“If we are overemphasizing individual responsibility and behavior as the only cause of Type 2 diabetes, then what that means is that once you have diabetes, you are blamed because we make the assumption that it is due to your behavior and your bad choices.”

This attitude adds more stress to a condition that already creates social problems: People with Type 2 may have to eat at specific times, they suffer from frequent urination, and many of them must test their blood glucose levels by pricking themselves — sometimes several times a day, often when they are at work or in another public setting. Some have to inject themselves with insulin.

Even health-care workers can exude disapproval — and patients may see criticism when none is intended. “Imagine a young primary care physician or a slim dietitian. It is really important how they talk to patients” so they don’t convey that it’s the patient’s fault, Reddy says.

People with the much less common Type 1 diabetes, in which the body’s immune system destroys the insulin-producing cells in the pancreas, often feel lumped together with those who have Type 2 even though being overweight has nothing to do with that type of the disease.

“A lot of people assume I’m Type 2 diabetes,” says Dennis Hubert, 53, who was diagnosed with Type 1 at age 17. “People see I’m heavy and their first assumption is that I did it to myself. That’s one thing that really gets down to my core.”

Smith, on the other hand, says that “from the outside, I don’t look like I have anything wrong with me.” But nearly every day, she says, she doubts herself and fends off the insecurities her disease brings. One way she keeps her spirits up is by riding with a friend on his Harley, and she has become friends with a group of motorcyclists. At weekend breakfasts, Smith explains what she eats and why, and encourages the men to adopt some of her habits — such as ordering smaller portions in restaurants. Now, instead of mountainous plates of food for each of them, four of the “big-bellied guys” split meals with one another.

“They say, ‘I’m thanking you for this, Patti. You’re saving us money,’ ” Smith says. But she benefits, too — from talking comfortably about how she manages her diabetes. She says, “If you aren’t open about it, you feel you are alone.”

Related:

29 million Americans have diabetes — but a quarter of them don’t realize it

Researchers campaign against Americans’ sweet tooth with public health initiative

9 steps you can take toward healthier habits

What experts in diabetes are saying about education and prevention