Eating an extra 100 calories a day can cause someone to put on almost a stone in a year and increase their risk of cancer, campaigners have warned.
The World Cancer Research Fund (WCRF) said just this small amount – the equivalent of around a biscuit or two – could be potentially damaging.
To mark the start of Cancer Prevention Week today, the charity has launched the “100 Calorie Challenge” to encourage people to make changes to their diet to cut their risk of serious diseases.
Research has found that rather than making big alterations to lifestyle, an effective way to combat rising obesity levels is for people to make small changes in the amount of calories they consume and energy they use.
The numbers of adults and children classed as overweight or obese has soared in Scotland in recent years, with little evidence to suggest levels of obesity have yet to start falling.
Last month, figures revealed that one in seven five-year-olds in Scotland is clinically overweight or obese. They also showed that the number of Scots expected to develop cancer now stands at two out of five, compared with the previous estimate of one in three.
WCRF said an extra 100 calories a day could cause an 11lb increase in body weight in a year. Being overweight or obese is second only to smoking as the biggest risk factor for several types of cancer, including bowel, breast, pancreas, womb and throat cancer.
In the UK, 18 per cent of cancer cases are linked to being overweight or obese and could be prevented if everyone were a healthy weight – amounting to about 22,110 cases of cancer a year.
Kate Mendoza, head of health information at WCRF, said: “Anyone who’s ever tried dieting will know how difficult it is to lose weight, so we’re proposing the 100 Calorie Challenge so people can avoid putting on that extra weight in the first place.
“Cutting 100 calories from your daily diet is relatively simple – equal to cutting out one-and-a-half digestive biscuits – but the cumulative effect of such a small daily amount could prevent nearly an extra stone in body weight over a year.
“This strategy of small changes could prevent additional weight gain and help reduce cancer risk. Small sustainable changes are easier for people to follow and better than larger ones that can’t be maintained.”
The campaign has been backed by diet and fitness guru Rosemary Conley, who said: “The 100 Calorie Challenge is a great way to help people achieve a healthy weight and reduce their risk of getting cancer.”