Fruit and vegetables such as apples, pears, blueberries, strawberries and radishes - that are high in a key compound - may help prevent weight gain.
Research from Harvard University and the University of East Anglia has found that even a single serving per day of fruit and vegetables with high levels of flavonoids can help maintain a healthy weight.
Flavonoids are plant compounds found in foods and drinks, including a wide range of fruit and vegetables, tea, chocolate and wine.
They have long been celebrated for their antioxidant effect, thought to help prevent cell damage.
In the study, published in the British Medical Journal, experts examined data for 124,086 men and women in the US over a 24-year period.
The research focused on three large groups - women with an average age of 36 at the start of the study, women aged 48, and men with an average age of 47.
Professor Aedin Cassidy of 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.
"We found that an increased consumption of most flavonoids was associated with weight maintenance, and even a modest weight loss.
"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."
Prof Cassidy said the strongest links were found for foods containing anthocyanins, found in blueberries, strawberries, cherries, blackberries, grapes, radishes and blackcurrants.
"We also found that flavonoid polymers - found in tea and apples - were particularly beneficial, along with flavonols, found in tea and onions," he said.
The experts found that consuming just a small amount (a standard deviation) of flavonoids was linked to maintaining a healthy weight, and even a very small weight loss (0.1kg or 0.22lb).
However, they said many fruits provided more than one standard deviation increase - for example a single serving of blueberries contains up to 121mg of anthocyanins and tea contains a range of flavonoids, including flavonols, flavan-3-ols and their polymers.
This meant that choosing flavonoid-rich fruits and vegetables could help people shed up to 1lb or 2lb.
Prof Cassidy said:
"We hope that the results will help refine previous dietary recommendations and provide guidance on which specific fruits and vegetables to choose for preventing obesity and its potential consequences.
"Losing or preventing even small amounts of weight can reduce the risk of diabetes, cancer, hypertension and cardiovascular disease."
BEST FRUIT AND VEG FOR MAINTAINING HEALTHY WEIGHT:
Raspberries
Blueberries
Blackberries
Strawberries
Blackcurrants
Cherries
Grapes
Plums
Radishes
Tea
Cocoa
Pears
Apples
Citrus fruits such as oranges and grapefruits
Onions
Peppers
Aubergines
