Kerri Waldron
Yo-yo dieting more than doubles the risk of dying young, warns recent research. Seesawing weight, blood pressure, cholesterol and blood sugar levels may be even more dangerous than staying fat, say scientists.
The study shows that heart attacks and strokes are more common among people who shed and regain the pounds repeatedly. The study of 6,748,773 people found those in the top 25 percent for variability were two and a quarter times more likely to die from any cause over the next five and a half years.
In particular they were 43 and 41 percent more vulnerable to a heart attack or stroke, respectively. It is the largest analysis of its kind and adds to growing body of evidence about the dangers of yo yo dieting.
Senior author Professor Seung-Hwan Lee said: “Healthcare providers should pay attention to the variability in measurements of a patient’s blood pressure, cholesterol and glucose levels as well as body weight. Trying to stabilise these measurements may be an important step in helping them improve their health.”
Earlier studies have suggested on-off dieting increases blood pressure – which can lead to heart attacks and strokes. Endocrinologist Prof Lee, of the College of Medicine of the Catholic University of Korea in Seoul, said maintaining the same figure may be healthier.
His team based their results on data from the Korean National Health Insurance system. The participants had no previous heart attacks and were free of diabetes, high blood pressure or high cholesterol at the outset.
All had at least three health examinations between 2005 and 2012 – with every two years being the recommended routine. This provided comprehensive records of body weight, fasting blood sugar, blood pressure and total cholesterol. It is the first study to find high fluctuations in weight or the other three risk factors is harmful in healthy people – especially when two or more are present.
As these could be caused by good as well as bad changes the researchers looked separately at those who were more than five percent improved or worsened on each measurement. There was a significantly higher risk of death in both groups, reports the journal Circulation.
Prof Lee said the study was observational so it cannot prove fluctuations in weight and other risk factors causes heart attacks, strokes and deaths. It also did not delve into the reasons behind the changes in measurements. But he added: “It is not certain whether these results from Korea would apply to the United States.
“However, several previous studies on variability were performed in other populations, suggesting it is likely to be a common phenomenon.”
People who yo-yo diet tend to have higher blood pressure, heart rates, cholesterol and blood sugar levels. And these don’t go back down when they lose weight. Studies on mice even show it can cause DNA damage which may affect the heart. Last year a US study of 4,630 people tracked for 25 years found those who yo-yo dieted were more likely to have high blood pressure.
It showed sticking to a stable and healthy weight combated hypertension more effectively than refraining from smoking, drinking little to no alcohol, exercising or eating plenty of fruit and vegetables. It was the first to examine the effects of yo-yo dieting over such a long time. High blood pressure, or hypertension, is known as the ‘silent killer’ because it can cause few symptoms.
About 16 million people in Britain – one in four adults – suffer from it. Approximately 62,000 unnecessary deaths from stroke and heart attacks occur due to poor blood pressure control – meaning that about 170 people die each day. Another American team who followed 158,000 post-menopausal women for more than 11 years found those who lost weight and put it on again were three and a half times more likely to die suddenly from heart abnormalities.
They were also 66 per cent more likely to die from clogged arteries. Fat women who stayed overweight, or women who piled on the pounds and did not lose it, saw no such increase in risk. The definition of yo-yo dieting is gaining or losing more than 10 pounds on four separate occasions regardless of time – whether in a year or in a few months.
Source: bing.com
