The results offer significant support to Europe's sizeable health foods industry, suggesting that not only weight loss products but also those that help prevent weight gain, can play a role in protecting against heart disease.
Metabolic syndrome is a clustering of risk factors that increases a person's risk of heart disease. After 15 years, only 3.6 per cent of the study participants who had maintained their weight had developed metabolic syndrome, compared to 18 per cent of those whose weight had increased.
"Weight stabilisation may be easier to achieve than significant weight loss for many people, and there are clear benefits to maintaining stable weight," concluded Donald Lloyd-Jones, assistant professor of preventive medicine and of medicine at Northwestern University Feinberg School of Medicine.
Presenting the results at the American Heart Association's annual conference, Lloyd-Jones added: "Regardless of whether you are overweight or normal weight in young adulthood, it's really important, at a minimum, not to gain any more weight. That's a critical part of the message."
The Coronary Artery Risk Development in Young Adults (CARDIA) study, funded by the US National Institutes of Health, followed over 5,000 men and women for 15 years.
The new study selected 2,475 study participants who were initially aged 18 to 30. It examined the relationship over time between weight and several cardiovascular disease risk factors: high blood pressure, high glucose (sugar) levels which can indicate risk for diabetes, high triglyceride levels, low levels of good cholesterol, and a large waist.
Metabolic syndrome is defined as having at least three of these risk factors.
Investigators found that on average as body mass index, an indicator of obesity, increased, adverse changes in these cardiovascular disease risk factors occurred. Over the 15 years of the study, these changes produced substantial differences in risk factor levels.
Normal-weight men who maintained their weight had only a 1 mg/dL rise per year in triglycerides compared to a 4 mg/dL per year increase in those who had gained weight. After 15 years, that translates into a total increase in triglycerides of 60 versus 15 mg/dL in those who gained compared with those who maintained stable weight, said the researchers.
Normal weight women showed almost no increase in triglyceride levels when they maintained their weight, compared to an almost 2 mg/dL rise per year for those whose weight had increased.
Of the adults studied, more than 80 per cent had gained weight over the years and had negative changes in heart disease risk factors, compared to 18 per cent who had maintained their current weight and showed no significant change in risk factors for heart disease.