(CNN) -- Kay and Mike Alexander's journey to obesity is a familiar road for many married couples. Neither was overweight when they met on a coffee break at work. Nor were they obese when they cut their wedding cake, iced with an image of Star Trek's USS Enterprise.
But over time, working and raising foster children in Kalamazoo, Michigan, the pounds added up.
"I put on about five to 10 pounds per year for 20 years," Kay Alexander says.
At age 55, she says she was "one blood test away from being diagnosed with Type 2 diabetes," when she started having chest pains.
Remembering that her father died of a heart attack when he was only 55, she went to the hospital. There, a doctor told her she too had had a heart attack -- one that, without medical attention, would have left her with only hours to live.
"That was the big trigger," she says.
At 5 feet, 4 inches tall, she was closing in on 300 pounds. She knew she had to lose weight, but also knew from experience that dieting wasn't the answer. Her husband, whose body mass index had increased from 23 to 34 since graduating college, agreed.
So instead of cutting their portion sizes down to starvation rations, the Alexanders decided to rely on their training as chemical engineers. They began tinkering with recipes to see if they could reduce the calorie counts of their favorite foods.
"We put our food on a diet," says Kay Alexander. "Dilution is the solution to pollution. That (theory) doesn't work for environmental engineering in the long run, but does work for food."
The Alexanders' strategy is a powerful one, says Rachel Berman, director of nutrition for Caloriecount.com, a site Kay Alexander used to calculate calorie totals for her new recipes. Berman, also a registered dietician, uses the Alexanders' approach in counseling and has seen patients experiment with it in their homes.
"Deprivation does not work in the long run," she says. "And Kay and Mike are a great example of how to turn this into a lifestyle change."
It took four or five months of experimenting to re-engineer some of their favorite recipes and start losing weight, according to Mike Alexander. The key to the new recipes, says his wife, was minimizing the amount of carbohydrates and maximizing the amount of vegetables.
"A lot of what we did was kind of tricking the mind and stomach," she says. "For every food we took out, I tried to put one new one in."
They reinvented many of their favorite dishes, such as mashed potatoes, substituting cauliflower for the potatoes. They traded the white rice in chicken stir-fry for high-fiber pita wraps. They even replaced the pasta in baked spaghetti with a self-invented broccoli slaw.
Over the next year and a half, Kay Alexander lost more than 130 pounds. Mike Alexander lost 65.
"We're still trying to do cookies and treats that are low-calorie," he says. "She has a meringue cookie that's 4 or 5 calories. We believe food companies should engineer their foods to be low-calorie, like we've done."
By using a scientific approach, the couple turned weight loss into a project they could work on together. Before they started experimenting with recipes, Mike Alexander did most of the cooking from boxed foods. Now they collaborate on recipes; she does most of the cooking and he handles the cleanup.
"It was part intellectual and part doing it," he says. "It was really good for our marriage."
In addition to counting calories, Kay Alexander exercised more. She started out wearing a pedometer. Over time, her steps increased from 3,500 per day to about 17,000.
"(The amount I now walk) almost makes me like an Amish person," she jokes.
Exercise significantly increased Kay Alexander's energy level, says Taylor Rose, 19, who calls the Alexanders her grandparents. She describes her grandmother as a health nut, and says she enjoys going shopping with her now because the older woman doesn't have to stop every few minutes to catch her breath.
"We can share clothes now," she says. "I love that."
Kay Alexander is retired; her husband will join her in about six years. He's glad he chose to drop the weight slowly because it is more indicative of a successful lifestyle change than a diet. He knows retirement will expose him to more chances to eat poorly and excessively.
"I'm trying to develop how I'm going to keep (the weight) off," he says.