Two-thirds of teenagers were too fat to join the Army before rules on weight were relaxed, it has been revealed.
Obesity among the young may hit Army recruitment, says the NAO
The Body Mass Index of all recruits had to be below 28 under the old rules. Earlier this year, this was increased to 32, within the "obese" range.
Officials said the BMI requirement was being relaxed as it had been decided larger men could still be fit.
But now the National Audit Office has revealed that only a third of all 16-year-olds met the old target.
In its report on recruitment and retention in the armed forces, the NAO said increasing levels of obesity and resultant health problems among young people reduced the number of young people able to join the services.
There has been criticism over the use of the BMI scale to assess whether people are overweight. Celebrated Hollywood idols George Clooney, Brad Pitt and Matt Damon are all technically obese.
The scale compares height to weight and takes no account of people - like the Hollywood stars - who tip the scales because of their muscle mass.
"Increasing levels of obesity and resultant health amongst young people reduces the number of young people able to join the services," the NAO said.