Blueberries are one flavonoid-rich food that could help you maintain a healthy weight Reuters

Food high in flavonoids can help people maintain a healthy weight, according to a study published in the British Medical Journal. The department of nutrition at the Harvard TH Chan School of Public Health and University of East Anglia's Norwich Medical School studied 124,086 people across the USA over 24 years.

Participants self-reported their weights every two years and their diet, lifestyle habits and health problems every four years between 1986 and 2011. After adjusting the data for factors that would otherwise affect results, the researchers found that consuming a small amount of flavonoids correlated with maintaining a healthy weight, or even modest weight loss.

Prof Aedin Cassidy, from UEA's Norwich Medical School, said: "Most adults gain weight as they age and even small increases in weight can have a substantial impact on risk of high blood pressure, developing heart disease, cancer or diabetes – so strategies to help individuals maintain a healthy weight in middle age are needed."

"We found that an increased consumption of most flavonoids were associated with weight maintenance, and even a modest weight loss. The results were found to be consistent across men and women, and different ages. However losing even small amounts of weight, or preventing weight gain, can improve health and these modest effects were seen with a small, readily achievable increase in intake of many of these fruits. Just a single portion of some of these fruits per day would have an important impact on health at a population level.

Flavonoid-rich foods

  • Blueberries
  • Strawberries
  • Cherries
  • Blackberries
  • Grapes
  • Radishes
  • Blackcurrant
  • Tea
  • Apples
  • Pears
  • Onions

"The greatest association was found for anthocyanins – which are found in blueberries, strawberries, cherries, blackberries, grapes, radishes and blackcurrant. We also found that flavonoid polymers – found in tea and apples – were particularly beneficial, along with flavonols – found in tea and onions."

The research team hope that eating fruits and vegetables rich in flavonoids could help people lose up to one or two pounds.

"We hope that the results will help refine previous dietary recommendations and provide guidance on which specific fruits and vegetables to choose for preventing of obesity and its potential consequences. Losing or preventing even small amounts of weight can reduce the risk of diabetes, cancer, hypertension and cardiovascular disease."

"In the US, for example, most people consume less than one cup (portion) of fruits, and less than two cups of vegetables daily. This is below the recommended daily intake and should be increased to two cups of fruits, and two and a half cups of vegetables – which equates to the UK's recommended 'five-a-day'."

"And people may be able to improve the health benefits of eating fruit and vegetables by choosing those including high levels of flavonoids, such as apples, pears, and berries."