Yo-yo dieting could increase risk of sudden cardiac death by three and a half times, according to a study that looked into the link between the weight of post-menopausal women and heart health.

The study was led by Dr. Somwail Rasla of Memorial Hospital of Rhode Island, and presented to the American Heart Association earlier this week.

Researchers looked at 153,063 post-menopausal women, who reported their weight. The women were split into groups, those with a Body Mass Index (BMI) less than 25 (‘normal’), between 25 and 29.9 ('overweight') and over 30 ('obese'). The women also recorded their weight history – and were classed as 'stable', 'weight maintaining', 'steady gaining' or 'weight cycling'. The final term referred to those whose weight went up and down by more than 10 pounds – colloquially called yo-yo dieting.

The women’s health was followed for 11.4 years. In that time, 2,526 suffered coronary heart disease deaths and 83 died from sudden cardiac arrest.

The researchers looked at the categories that these women fell into. They found that overweight and obese women who ‘weight cycled’ did not increase their risk of heart disease-related deaths.

Those of ‘normal’ weight who were classified as ‘weight cyclers’, however, were 3.5 times more likely to die from sudden cardiac death than those who maintained a stable weight, and 66 per cent more likely to die from coronary heart disease.

‘Weight cyclers’ were 3.5 times more likely to die from sudden cardiac death, and 66 per cent more likely to die from coronary heart disease.

Head researcher Rasla said: "Normal-weight women who said 'yes' to weight cycling when they were younger had an increased risk of sudden cardiac death and increased risk of coronary heart disease, which can lead to heart attacks and other serious issues."

The more often the women lost and regained weight had an effect, too – Rasla said: "The more cycling [the more often weight was lost and regained], the more hazardous [to their hearts]."

According to Rasla, 20 to 55 per cent of the female population in the US is prone to weight cycling, compared to 10 to 20 per cent of women.

Rasla believes the harm may come as a result of sudden increases in weight raising blood pressure, cholesterol and body fat quickly. The levels drop when the woman loses weight – but they don’t return to ‘baseline’ or ‘normal’, and when the woman gains weight again they’re increase – and so on.

It is worth remembering, however, that this study asked the women to self-report their weight and history, and also didn’t look at outside factors that might be causing women of a normal weight to lose or gain weight. Stress, lifestyle, or illness (pregnancy was accounted for!) may have caused these women to yo-yo on the scales, and this could also have accounted for their increased risk of heart problems.

Read more about the study here.

Looking to lose weight sustainably? Check out our article 'How to Lose Weight through Cycling'.