Office chairs, once designed for a modest 15 stone, are now being increasingly ordered with a breaking strength of 25 stone, and discreet arm-less chairs are being kept by some restaurants to cater for customers who just can't fit between the arms.
Cars are being designed for occupants who are assumed to be 18 pounds heavier than they were in 1961. One sports stadium in north America which replaced its seats with larger-size versions to fit its supporters' backsides found its capacity had shrunk by 5,000.
Obesity is becoming a major epidemic in the west and aircraft designers are now allowing extra weight for every passenger, according to a report in the British Medical Bulletin. Designers of beds, chairs, and cars have also had to acknowledge that their customers are bigger than they used to be, says the report, which adds that among some groups obesity rates are now greater than 50 per cent.
The report's author, Dr Richard Prentice of the Medical Research Council's Dunn Clinical Nutrition Centre at Cambridge, says that body mass index, the measure of obesity, has been increasing steadily in the UK and other affluent countries since the turn of the century.
"Such changes are graphically illustrated by the fact that Boeing's aeroplane designers have had to increase the assumed weight of each passenger by over 20 pounds since their first airliners took to the skies," he says. "Designers of clothes, and beds and chairs and cars, are all acknowledging that this increase in girth is not a temporary deviation: it is here to stay.
"They have gradually been hiking up allowances, but aircraft designers are not the only ones. Vehicle seats, restaurant seats and a lot of other things are also affected, particularly in the USA. It is a problem that is not going away."
Bill Gulliver, an expert on test methods and standards for the Furniture Research Association, says: "The European standard we use for chairs is a weight of 16 stone, but a lot of companies are now insisting on 24 stone. The reason why managements, particularly in the large companies, are asking for them is because it is embarrassing to have to tell larger people they must have a special chair. It is easier if everybody gets the 24-stone chair."
John Makepiece, one of Britain's foremost furniture designers, says: "We tend to design for special situations so we come across circumstances where the chief executive of a company may say that a regular visitor is very large and asks us to make sure that the chairs don't make them feel embarrassed or uncomfortable.
"Nowadays people all want to be in armchairs at the dining table and that can cause problems. One does come across situations in a restaurant where they will keep a side chair available for people who are too big to fit between the arms."
Roger Coleman, senior research fellow at the Royal College of Art and specialist in ergonomics, says: "Obesity is a major problem and raises a lot of design issues. The majority of men aged over 60, for instance, cannot get out of a chair without using their arms to push themselves up."
Most of the car industry uses data dating back to 1961 for its ergonomic design work, but Jaguar Cars commissioned a study which found that the average weight of occupants needed to be changed by 18 pounds.
"We carried out a major study on driver dimensions and we created a Jaguar mannequin which is larger than the industry standard that dates back to 1961. What we found is that the assumed average weight of the driver and passenger has increased by around 18 pounds for each person," says Mark Humphreys, Jaguar's senior ergonomist.
A Boeing spokesman in Seattle says: "We recognise that people are getting heavier. The weight allowance for passengers has increased for a number of reasons. We take into account a combination of factors including the passenger and also what they take with them. Weight may be one factor, but people also now take on more luggage."
With one in five middle-aged adults in Europe now classed as obese, the rush to cater for the larger body is not confined to aircraft designers.
While the designers take account of changing shapes, the Bulletin report points out that not all people regard obesity as a problem and says that health professionals tackling the problem need to be aware that some people have other views about obesity.
"In these days of political correctness, the gloomy tone of these predictions may appear hostile to the self-help and self- protective organisations such as Naafa, the North American Association for Fatness Acceptance, whose view is that the risk of obesity and the benefits of weight loss are grossly overstated by a tyrannous medical profession bent on making their life a mystery," says Dr Prentice.
The report warns how easily obesity can be achieved when it records that the world's fattest man died recently, weighing 73 stone and aged in his mid forties: "Even this enormous accumulation of fat required an excess equivalent to only a small bar of chocolate each day."Reuse content