ANALYSIS - The rise in obesity in the UK has been primarily caused by a decline in physical activity at home and in the workplace, not an increase in sugar, fat or calorie consumption.
These are the findings of a new report The Fat Lie by Christopher Snowdon published this month.
The report says that the rise in obesity in recent decades is popularly believed to be the result of increased consumption of calories in general and sugar in particular.
And the belief that diet is the cause of obesity has led campaigners to call for product reformulation, fat taxes and other policies to reduce calorie consumption at the population level.
The report’s author describes the popular cries for a reduction in consumption of various aspects of the diet as “anti-market”.
He says that all the evidence indicates that per capita consumption of sugar, salt, fat and calories has been falling in Britain for decades.
The report says that according to the British Heart Foundation “overall intake of calories, fat and saturated fat has decreased since the 1970s. This trend is accompanied by a decrease in sugar and salt intake, and an increase in fibre and fruit and vegetable intake”.
Mr Snowdon said “This statement may come as a surprise to some people, but it is factually correct.”
He said that the Department for Environment, Food and Rural Affairs (DEFRA) has carried out annual surveys of the British diet since 1974 based on diet diaries compiled by a cross-section of the public and are supported by till receipts.
He said that the data indicate a significant decline in daily calorie consumption per capita in the UK over the last 40 years, from 2,534 in 1974 to 1,990 in 2012.
Consumption of protein, cholesterol, sodium and carbohydrates (of which sugar is one) have all declined since 1974.
The consumption of almost all of the nutrients in the British diet have either declined or held steady since the DEFRA study started.
“This represents a decline in energy consumption of 21.5 per cent,” said Mr Snowdon.
Per capita sugar consumption has fallen by 16 per cent since 1992 and per capita calorie consumption has fallen by 21 per cent since 1974.
“If people are ‘being bombarded every day by the food industry to consume more and more food’, as some claim, then the industry has failed (Peretti, 2012),” the report says.
“Consumption of calories - and of sugar and fat - has fallen significantly while obesity rates have risen.”
Mr Snowdon adds that since 2002, the average body weight of English adults has increased by two kilograms.
“Obesity is caused when individuals repeatedly consume more calories than they burn off. Many public health campaigners portray Britain’s obesity ‘epidemic’ as being caused by the increased availability of high calorie foods, sugary drinks and larger servings in restaurants,” the report states.
Other surveys started in the 1990s including the National Diet and Nutrition Survey indicate that that average calorie consumption has fallen by 9.8 per cent for 19-64 year olds since 1986/87.
The NDNS study also shows that consumption of fat (including saturated fat) has declined amongst all age groups and consumption of carbohydrates (including sugars) has fallen amongst all age groups except pensioners.
Mr Snowdon admits in the report that measuring the diet of the nation is not an exact science, because researchers rely on individuals keeping track of what they eat over a period of several days and it is well known that people tend to under-report the amount of food they consume due to a desire to deceive or - more commonly - a tendency to forget.
The report says that the reasons for an increase in obesity and even many of those who are not obese are overweight, is down to a change of lifestyles.
While there has been a trend for some to take part in regular physical activity, the changes to more sedentary occupations has had the greatest effect on the weight of the population.
“The transition from manual labour to office work saw jobs in agriculture decline from 11 to two per cent of employment in the twentieth century while manufacturing jobs declined from 28 to 14 per cent of employment (Lindsay, 2003),” the report says.
“Britons are walking less and cycling less. Only 18 per cent of adults report doing any moderate or vigorous physical activity at work while 63 per cent never climb stairs at work and 40 per cent spend no time walking at work
“Outside of work, 63 per cent report spending less than 10 minutes a day walking and 53 per cent do no sports or exercise whatsoever.”
The report concludes that the weight of evidence strongly suggests that the rise in obesity since 1980 has not come about as a result of increased energy consumption, rather it has come about despite a marked reduction in energy consumption.
It says that there is also a tendency to import evidence from the US and draw conclusions from it for the British situation.
However, the report says that in contrast to the UK, calorie consumption in the US rose in line with obesity rates for many years.
The report concludes that there is a deeply rooted belief that obesity stems from sugar and/or calories consumption but now the role of chronic physical inactivity is beginning to be acknowledged as the driver of rising obesity.
You can view the full report by clicking here.