Growing evidence suggests that overall cancer incidence and mortality resulting from overweight and obesity is increasing, potentially thwarting other prevention and treatment efforts aimed at reducing these dire statistics.
A number of recent academic studies, presented at the recent AACR International Conference on Frontiers in Cancer Prevention Research, provide worrying reading for the food industry, and present regulators with another headache.
"Given the trends in obesity and the increasing evidence of a broad range of cancers caused by excess energy balance, the projected burden of cancer over the coming years is worrisome," said Graham Colditz, professor of epidemiology with the Harvard School of Public Health.
The food industry is already taking a lot of the heat. The recent introduction of nutritional guidelines in the UK has led to the banning of soft drinks and high-fat snacks from vending machines in schools, while France has banned such machines from schools altogether.
And figures released in March by the International Obesity Task Force (IOFT) showing that the number of overweight European kids is still rising by 400,000 a year has piled on yet more pressure. more than 200 million adults across the EU may now be overweight or obese.
What is especially worrisome is the fact that the latest projections represent a departure from an earlier report prepared in 2002 by the International Agency for Research on Cancer Committee on Weight Control and Physical Activity (IARC), based on European estimates for cancer prevalence.
That report concluded that overweight and obesity are related to cancers of the colon, endometrium, kidney and esophagus, as well as postmenopausal breast cancer. "Given the trend to increasing prevalence of obesity, these estimates are conservative," said Colditz.
It is not all bad news however. A MORI survey commissioned by the National Consumer Council (NCC) suggests that two-thirds of adults - 63 per cent - in Great Britain have changed their family's eating habits or activity levels in the past year, in order to lead a healthier lifestyle.
Top actions range from eating more fruit and vegetables, to increasing physical activity, cutting down on fat or switching to reduced fat products, and eating less convenience food. There is also greater awareness of the importance of consuming fatty oils from sources such as fish corn and vegetables.
The survey showed that social class, gender and marital status are all significant factors affecting diet and lifestyle. "People want to be provided with important information on diet and health - that is relevant for them - and choose their diet for themselves," noted the report.
In addition, it is clear that scientists are now more ready to accept that obesity is linked to cancer. This could lead to more research in this particular area and help raise consumer awareness.
The fact remains however that unless the issue is dealt with, the projected burden of cancer resulting from obesity may thwart other efforts to reduce cancer incidence over the next couple of decades. For example, poor eating patterns, generally referred to as the "Western diet," may contribute to increased incidence of breast cancer among African-American women, according to a large study presented at the AACR meeting.
"The epidemic of obesity will run counter to the improving trends, such as a decrease in current smoking, that may suggest the incidence of cancer can be reduced," warned Colditz.