Eating Tonnes of Fruit Could Stop You From Gaining Weight

In case you missed your mum's continual efforts to ply you with satsumas or those cheery public health posters reminding you to "get your five-a-day!", fruit is good for you and you should probably be eating more of it. As nice as it would be to survive off cream cheese bagels and Doritos, the potassium, dietary fibres, and cornucopia of vitamins found in fruit are kinda useful too.

And now, science has found yet another reason to mainline bananas. According to a new study from researchers at Harvard and the University of East Anglia (UEA) in Norwich, fruit containing flavonoids could help prevent weight gain.

A naturally occurring compound, flavonoids are found in a number of foods and drinks including chocolate and wine, but appear in high levels in blueberries, apples, and onions. They're rich in antioxidants and thought to help prevent cell damage, decrease fat absorption, and even increase glucose uptake in muscle.

The new study, published in the British Medical Journal this week, is one of the first to find an association between eating flavonoid-heavy fruit and vegetables and a reduction in weight gain.

Following 124,086 US men and women for up to 24 years, the study saw participants self-report their weight, lifestyle habits, and any recently diagnosed diseases via questionnaires every two years between 1986 and 2011. Every four years, they also gave information on their diet.

Using this information, researchers analysed the association between participants' intake of seven flavonoid subclasses and any changes in weight. Results were adjusted for dietary and lifestyle factors and were found to be consistent across men and women of different ages.

According to the study, the greatest association between diet and weight change was for anthocyanins (mainly found in blueberries and strawberries), flavonoid polymers (apples), and flavonols (onions). On average, men gained a kilo over a four-year period and women a couple of kilos, but those who ate more of these flavonoid-rich fruit and vegetables did not put on weight.

This led researchers to conclude that eating such foods could be an important tool in preventing obesity.

Professor Aedin Cassidy at UEA Norwich Medical School said: "There's a lot of interest in flavonoids with cardiovascular health and diabetes. We think the different subclasses [of flavonoids] have different effects. A lot of people, when they go on a diet, have to do something radical. This is basically saying that something which is good for you already may also be good for weight maintenance, particularly in middle age when weight gain is associated with increased chance of getting heart disease and strokes."

But those blueberries you've been topping your muesli with may not be a failsafe buffer against the middle aged spread. Other medical experts have warned that further trials are needed to fully understand the impact of flavonoids on long term health.

Speaking to the Guardian, Naveed Sattar, professor of metabolic medicine at the University of Glasgow warned: "In truth, individuals who eat more high-flavonoid foods have other habits which lead them to put on less weight—or other effects of high-flavonoid foods may be responsible, such as fibre content in fruits and vegetables. Hence, one must be very careful about recommending high-flavonoid foods as beneficial to health."

An apple may not be a sure fire way to keep the doctor away, but it's probably still worth eating one every now and again.