A lot of people struggle to maintain their ideal weight, but repeatedly losing and regaining pounds – known as yo-yo dieting – probably won't do your heart any favours.
A new study found that women who lost at least 10 pounds, but then put that weight back on within a year, were more likely to have risk factors for heart disease. The more times someone went on a yo-yo diet, the worse their heart health.
Yo-yo dieting also wasn't helping women keep their weight in a healthy range. The study found that yo-yo dieters were 82% less likely to be at an optimal weight.
"Weight cycling is extremely common – the range was zero to 20 cycles – and a history of one or more episodes of weight cycling was associated with a poorer health score," said study author Brooke Aggarwal. She's an assistant professor of medical sciences at Columbia University Medical Center in New York City.
The study included almost 500 women in the New York City area. Their average age was 37. Nearly two-thirds were from racial or ethnic minorities.
The average body mass index (BMI) of women in the study was 26 – slightly overweight. BMI is a rough estimate of a person's body fat based on height and weight measurements. A normal BMI is between 18.5 and 24.9, according to the US National Heart, Lung, and Blood Institute. Overweight is between 25 and 29.9, and over 30 is considered obese.
Almost three-quarters of the women reported yo-yo dieting at least once.
Yo-yo roller coaster
The researchers checked the women's heart health using the American Heart Association's "Life Simple 7" recommendations. These seven factors are thought to be a measure of how well people control their heart disease risk factors. The seven measures include eating healthily, exercising regularly, losing weight, quitting smoking, and managing blood pressure, cholesterol and blood sugar levels.
Women who had ever yo-yo dieted were 51% less likely to have a moderate total score on Life's Simple 7. They were 65% less likely to have a score that rated optimal, the study found.
The more a woman had dieted and quickly regained the weight, the worse her Life's Simple 7 score. Women who had never been pregnant seemed to be more impacted by the effects of yo-yo dieting.
"These women were likely younger, and the younger you start yo-yo dieting, the worse it may be for you. If you get on that yo-yo roller coaster early, your cardiovascular risk is increased," Aggarwal said.
So how might yo-yo dieting be bad for your heart health?
Aggarwal said this study didn't prove a cause-and-effect relationship. But she noted that when you lose weight, you tend to lose lean muscle, and when you regain it, it's often fat. And, she said, it's often fat that settles in the abdomen, which is linked to a higher risk of heart disease.
Keeping the body alive
Samantha Heller is a nutritionist with NYU Langone Health in New York City. She was not involved with the study, but commented on the findings.
"Our bodies don't understand why we do or don't have food. Our bodies just know when they get enough nutrients to survive," she said. "If you've been on a restricted diet, and then you start eating again, your body may start saving what it can because it doesn't know when food will come back. Your body is just trying to keep you alive, and over time, the body gets more efficient at this."
Heller said your body will drive you to get food if it thinks you need it. "Doesn't food taste much better when you're really hungry? That's the body driving you to eat and keep it alive."
What that means, Heller said, is it's best to "try to adopt a dietary pattern that we can keep forever". She suggested a mostly plant-based diet, such as the Mediterranean diet.
Aggarwal said she recommends "making small changes that are sustainable. Small changes don't cause a rebound effect."
Aggarwal is to present the findings at an American Heart Association meeting, in Houston. Findings presented at meetings are typically viewed as preliminary until they've been published in a peer-reviewed journal.
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