A study found those with more muscle mass earn more than underweight men.

Researchers from the universities of Strathclyde in Glasgow and Potsdam, Germany, analysed data from nearly 15,000 working men.

They found those classed as underweight on the Body Mass Index earn around 8 per cent less than their peers in the upper end of the healthy bracket.

The effect was most prominent in blue-collar industries, which are more reliant on physical strength, but there were echoes of it in white-collar jobs too.

The study, published in the journal Economics and Human Biology, says: ‘[The data] provides evidence for wage penalties against men who are deemed too light.

‘Even men in the lower bounds of the normal weight range are subject to wage penalties. Such a result is consistent with the “portly banker” effect, the notion that higher weight might reflect power and authority.

‘Consequently, underweight men might lack such an aura. This explains wage differences of 7 to 8 per cent between underweight men and those with BMIs [that attract the highest wage rates].’

It adds: ‘A higher BMI might well reflect more muscle mass, which tends to be productivity raising in blue-collar occupations.’

The study – which also examined 15,000 German women – confirmed the findings of previous research showing that among female blue-collar workers, the slimmest earn most and the obese the least.

In more middle-class occupations, rewards peaked at a BMI of around 21 – the lower end of healthy – and dropped off significantly on either side of this figure.

The study said: ‘Even women of normal weight are subject to wage penalties and thus it might be misleading to refer to this effect as an “obesity penalty”. [Instead] we find that a “slimness premium” exists.’

Jonny Gifford, of the Chartered Institute of Personnel and Development, said: ‘It is depressing that, in this day and age, looks are in any way a factor in how much people are paid.’ He added organisations should eliminate any ‘unconscious bias’ in the recruitment process.

More about: