DemonicMaster's blog: "vet"

As if clashing with your partner weren’t awful enough, new research suggests that hostile relationships could actually affect your fat metabolism—especially if you’ve ever dealt with depression.

In the study, 43 healthy couples married for at least three years filled out surveys on marital satisfaction, past mood disorders, and symptoms of depression. Then, researchers served them high-fat meals designed to mimic the nutritional profile of a typical fast-food meal.

Every 20 minutes for seven hours after the meal, researchers measured how many calories each participant burned. They also took a few blood samples to assess insulin (which regulates fat storage) and triglycerides, blood fats that could increase your risk of heart disease when present in large amounts.

In the midst of all this testing, researchers asked the couples to privately discuss and try to resolve at least one contentious issue in their relationships. The researchers recorded and assessed the discussions, and looked for verbal and nonverbal signs of hostility, like attributing actions to bad intentions, eye-rolling, and criticizing one another. “The arguments tend to be really reliable in assessing marriage hostility,” says study lead author Jan Kiecolt-Glaser, Ph.D., a psychiatry and psychology professor and the director of the Institute for Behavioral Medicine Research at The Ohio State University.

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Hostile partners who also had symptoms or a history of mood disorder burned an average of 31 fewer calories per hour, which could amount to up to a 12-pound weight gain in a year. They also had higher insulin levels for up to two hours after the meal, which stimulates food intake and increases the likelihood of obesity, according to study authors. The hostile, depressed group also had elevated levels of triglycerides.

Kiecolt-Glaser says the culprit here appears to be stress: Researchers already know that elevated levels of stress hormones can also affect your heart rate, blood pressure, immune system, and even slow wound healing. It’s no wonder stress slows down your fat metabolism as well.

If you think you’re in the clear because you’re not clinically depressed, not married, or because you eat super-healthy, think again: Kiecolt-Glaser says the results could apply to anyone in a hostile relationship, with or without a diagnosis of depression. “The idea is that if your primary relationship is going badly, what should be your major source of support becomes your major source of stress,” Kiecolt-Glaser says. Also: “A hostile relationship could certainly affect health even among people who eat healthier meals,” she adds.