IT’S TOO MUCH OF EVERYTHING THAT REALLY CAUSES CANCER

CONSUMING too many calories – whether they come from sugar, bacon, potatoes, toast or blueberries – will eventually lead to you gaining weight. And being overweight or obese increases your risk of 13 different types of cancer, including bowel, stomach, pancreatic, liver and post-menopausal breast cancer.

In fact, it’s the single biggest trigger for the disease in the UK after smoking.

Naveed Sattar, professor of metabolic medicine at Glasgow University, says: ‘Sugar doesn’t cause obesity or cancer. But consuming excess calories will make you put on weight, and the extra weight will increase your risk of cancer.’

Mangesh Thorat, of the Centre for Cancer Prevention at Queen Mary University of London, adds: ‘We know the most important thing for most cancers is keeping your weight down. Other than that, relating to diet, there’s nothing specific or evidencebased as an intervention.’

Your risk increases the longer you remain overweight – but small changes, maintained over time, can make a huge difference.

An early sign that weight loss may have a protective effect comes from the work of Roy Taylor, professor of medicine and metabolism at Newcastle University. He pioneered a very low-calorie diet that can, in some patients, reverse type 2 diabetes.

Participants consumed 800 calories a day for 12 to 20 weeks by drinking low-cal shakes.

They then reverted to the Government’s EatWell plate, which allows a third of the diet to be carbs – and consumed plenty of wholegrains, fruit and vegetables, lean meats and pulses.

Their progress was monitored and compared with a group who didn’t follow the programme or any other weight-loss plan.

After a few months, the majority of those on the diet had normal blood sugar levels, and no longer needed medication for diabetes.

Two years later, many had maintained their health.

But there was a surprising additional finding. In the group who didn’t follow the plan, there were five weight-related cancer cases – and none among those who did diet.

Prof Taylor said losing weight may affect the speed at which cancer grows. Prof Sattar adds: ‘Why weight loss may protect against cancer is unknown, but in women, obesity can affect the sex hormones which can then accelerate the growth of certain types of cancer, particularly endometrial – cancers of the womb lining. Those who put on weight will accumulate fat in the liver, which drives inflammation, leads to scarring and, eventually, to liver cancer. ‘There are other drivers, but we just don’t know yet what they are. The only certainty is that there is a link with obesity.’

And don’t forget to consider alcohol as part of the weight-loss equation. An evening glass of wine or a pint of beer contributes to your daily calorie total – and alcohol itself is a risk factor for cancer, even independent of weight.

The World Cancer Research Fund reports that breast, bowel, liver, stomach, mouth and oesophageal cancers are all strongly related to alcohol.

In most cases, the risk begins to rise if you’re consuming two to three units every day – that’s just one medium glass of wine.