A new weight-loss method could be the simplest diet ever - as it involves replacing just one between-meal confectionery snack with a handful of berries.
Research showed that when people swapped a confectionery treat for a berry snack with the same energy content, considerably fewer Calories were consumed at their next main meal, the research found.
This suggested that the simple change in habit alone could reduce a person's Calorie intake by nearly 1,000 Calories a week.
The reduction in Calories - the same as 20 WeightWatchers points - would be expected to produce a loss of around 1lb of body fat per month, and much more if alongside exercise and other healthy-eating choices, according to researchers.
Seasonal Berries commissioned Loughborough University to conduct the research and has also launched the Snack Smart berry challenge, in an effort to help change Britain's snacking habits and improve the nation's health.
Dr Lewis James, from the School of Sport, Exercise and Health Sciences at Loughborough University, who conducted the research, said that anyone who does the simple swap could feel the effects on their health and waistline.
He said: "Our research shows that an afternoon snack of mixed berries decreases energy intake at dinner. It's a simple method that might help people control and lose weight.
"There are a number of potential health benefits of consuming berries, but this is the first time that consuming them as a snack has been shown to reduce how much people eat during the next meal of the day. The cumulative effect of the reduced Calories could help people lose the extra pounds without them having to make an effort, or even noticing."
He added that current data suggests that only about 30 per cent of British adults are meeting the Department of Health recommendations to consume at least five portions of fruit and vegetables a day.
The new research comes after a separate study revealed that most people who make a New Year's resolution to eat more healthily fall off the diet wagon by the middle of February.
The survey of 1750 people who began a new diet regime in the first week of January found that most had ended by February or March, with the average date of February 15.
Laurence Olins of Seasonal Berries which commissioned both studies said: "Most of us have tried to lose weight by following the next diet craze, but they often demand huge sacrifices. This study shows that by giving up just one snack and replacing it with a handful of delicious berries, we could shed up to a stone in a year.
"I would challenge anyone to give it a try and see how they feel in a month's time. We're not promising miracles but I'm sure you'll be surprised by the results."
In the research trials, which were carried out over four months, 12 participants tested the effects of swapping a confectionery snack with a handful of berries - strawberries, blueberries, blackberries and raspberries - with the same energy content.
An hour after the snack, participants were told to eat a pasta dinner until they were "comfortably full and satisfied".
When participants had eaten the sugary snack they were found to consume nearly 20 per cent more food at dinner than those who had eaten a handful of berries, according to the results.
When volunteers snacked on berries they consumed, on average, 134 Calories less at dinner.
From the results, the academics from Loughborough University estimated that people switching from an afternoon confectionery snack to mixed berries might expect to reduce their energy intake by 938 Calories a week on average.
Given that 1lb of body fat is equivalent to around 3500 Calories, this reduction in daily energy intake would probably produce a loss of approximately 1lb of body fat a month - or a stone in a year.
To sign up to the challenge and receive health tips and berry recipes go to: www.seasonalberries.co.uk/snack-smart