Data collected from members of Nuffield Health clubs show that seven out of 10 have shown significant increases in their overall health.

The figures come from the operator's Health MOT initiative, launched in 2009, which is offered to every new club member at point of joining. Follow up tests are then conducted to ascertain the progress of each member.

Speaking to Health Club Management, managing director Laura Kerby said that a total of 36,000 people have now completed a second MOT, giving a "strong body of evidence" for the charity to analyse and work with.

She said: "The evidence shows how the programmes we've designed for members have helped improve their health scores.

"For example, 30 per cent of people reduced their cholesterol; 58 per cent lost weight and reduced their BMI; 73 per cent improved their aerobic fitness. Meanwhile, Fifty per cent of men and 43 per cent of women reduced their waist size."

Kerby said the results prompted a nationwide marketing campaign with a tagline of "Seven out of 10 members got healthier and fitter with us. Fact."

"We could have said nine out of 10 members, as most people have seen a few areas of improvement," she added. "But this is proper clinical evidence ratified by our medical director and signed off by Nuffield Health."

"If the industry tries to copy our message, we will challenge them and ask for proof, because we're serious about what we're trying to do with this."

To read the full interview with Laura Kerby, click here to access Health Club Management.