 Middle-age-spread is a real issue for both men and women who step into their 40s. As the metabolism slows down with age, and the muscle mass is reduced as well, it's increasingly difficult for the body to burn fat and stay fit. Although some handle it better than others, middle age is far from a breezy walk through the park for most people. Under these stressful circumstances, some people find comfort in food or alcohol, both of which also tend to show around the waist. But it's not all hopeless for those trying to fight the dreaded middle-age-spread. According to a new study of large proportions published in the journal BMJ , a minor change in diet can actually help you stay slim throughout your 40s. Here's how. The BMJ study on flavonoids and weight changes The BMJ study was the largest of its kind so far. It involved more than 124,000 middle aged and older people, who self-reported their weight once every two years, and their diet once every four years. The researchers analyzed this data over 24 years and, after adjusting for smoking and fitness activities, discovered that people who ate more flavonoid-rich foods maintained their weight better or even lost a few pounds. Flavonoids are natural compounds found in plants, where they perform a number of important roles. For instance, they are responsible for the proper communication between plant cells, as well as for creating attractive colors for bees and butterflies, which can help with pollination. Some flavonoid-heavy foods are strawberries, bananas, grapes, pears, onions, prunes, peppers, green tea and many others, but also chocolate and wine. It seems that with human beings, flavonoids might prevent unwanted weight gain. While most adults between 18 and 49 tend to gain one or two pounds every year, those involved in the study who adhered to a flavonoid-rich diet gained an average of 0.16 to 0.23 fewer pounds every four years. Berries showed the best results Different foods contain different types of flavonoids. The flavonoids that showed the best results in relation to weight gain were the anthocyanin, which can be found in strawberries, blackberries, blueberries , cherries, grapes, radishes and blackcurrants. Flavonoid polymers found in apples and green tea also showed promising results, as did the flavonols commonly found in tea and onions . While the results of the study might not seem impressive to those looking to lose weight fast, they are nevertheless extremely promising for people dreading the middle-age-spread. For them, it was outstanding news that something as simple as eating a handful of their favorite berries can help them maintain their weight throughout their 40s. <='' h1=''>The study published in the journal BMJ was only observational, but its authors had more in mind than the weight of the participants. As it is today, most Americans don't even eat one cup of fruit or two cups of veggies per day. By showing that some fruits like berries can be linked to weight loss, the researchers hoped to encourage people to eat more fruit overall. What's more, earlier studies on flavonoids indicated potential health benefits other than maintaining a desirable weight. Indeed, flavonoid-rich foods were shown to increase energy expenditure and therefore decrease fat absorption, while also working as efficient anti-inflammatories. The intake of flavonoids has been associated with a decreased risk of certain cancers, as well as with the support of the cardiovascular and nervous systems. At the end of the day, you just can't go wrong by eating a few more of your favorite berries. Not only will they help you maintain your desired weight through middle age, but they're also likely to help you fight a score of other life-threatening diseases. Sources include: TheTimes.co.uk BMJ.com Edition.CNN.com 