Why do some people crave more sugar than others?
The sugar industry has long claimed that its products have a high caloric content, but some nutritionists have questioned whether the claims are true.
Dr Chris Ragan of the University of York says he has been asked by the industry to review studies that purport to show the effectiveness of certain diet products.
“It’s the biggest industry I’ve been involved in in my career and it’s a huge industry,” he says.
“I don’t think it’s right to say these are safe and effective.”
“The scientific evidence is now showing that there’s no evidence that sugar is good for you.”
The American Academy of Pediatrics has also long warned against the harmful effects of sugar.
But Dr Ragan says his work has found evidence that consuming a diet rich in fruits and vegetables does not increase the risk of obesity.
He says that’s because fruit and vegetables are rich in fibre, antioxidants and other nutrients.
The World Health Organization recommends that people limit the amount of sugar they consume.
A spokesperson for the World Health Organisation says its health experts are working to find new scientific evidence to support its recommendations.
The International Food Information Council, an industry body, says it has a number of sources that it looks at when evaluating the health effects of food.
These include the National Institutes of Health (NIH), which is one of the government agencies that fund the World Food Programme, and the European Food Safety Authority, which provides data to the Food Standards Agency.
“There are a lot of studies that we’ve seen that have looked at the impact of sugar on weight and obesity,” says Dr Rago.
“We’ve seen an association between sugar consumption and weight gain, which is quite strong.”
But the US National Institutes for Health (NIA) says its own scientific evidence does not support the health claims made by the sugar industry.
“Research by the National Institute of Health is clear that the health benefits of sugar-sweetened beverages and sweetened foods are not as strong as advertised,” the spokesperson says.
The NIA says it supports the science and is not endorsing the claims of sugar companies.
“The NIA is working to provide the most comprehensive science on the health risks of added sugars,” the organisation says in a statement.
It says studies that have examined the health impacts of sugar have concluded that consuming added sugars is not associated with a higher risk of diabetes, cardiovascular disease, type 2 diabetes, stroke or certain cancers.
It also says that a substantial body of research is now suggesting that sugar does not cause obesity.
The American Heart Association says the evidence shows sugar is not linked to a higher level of risk of heart disease, heart attack or stroke.
It recommends limiting your intake of sugar, fruit and vegetable juices, as well as processed foods, and reducing the amount you eat in meals.