Obesity figures are increasing despite the number of people signing up for gym membership rocketing, a new report claims.
The scale of Britain's obesity epidemic was highlighted last month in a Government report which revealed more than half of adults and a quarter of children will be dangerously overweight by 2050.
But Dr Jennifer Smith Maguire, from the University of Leicester, said private gyms are failing to reverse the trend as most are used by richer members of society - leaving the poor struggling to tackle weight problems.
She said: "The commercial fitness industry benefits from the scientific legitimacy and political urgency bestowed on population health issues such as inactivity and obesity. But it is ill-equipped to address those issues for a number of reasons.
"In the US, for example, half of commercial health club members are in the top 20% of income earners.
"At the top end of the market, high income earners can afford excellent services and an 'enlightened' approach to fitness but at the bottom end of the market, middle and lower income earners can afford fewer and lower quality services and a 'factory' approach to fitness.
"And at the very bottom, excluded altogether from the market, are those individuals most likely to be inactive and obese."
"Low-cost or budget health clubs are now entering the UK, following an established trend in Germany and the USA (McFit and Planet Fitness). These clubs are built around a very large, well-equipped gym only - no swimming pools and other facilities. They are also based on a self-service model, with very few staff. Consequently, membership rates can be offered from £14 per month for unlimited use. The trade-off is a less personalised service for a lower price" - Ray Algar, Brighton