In the quest for the perfect physique men are increasingly becoming reliant on workout supplements, a study has revealed.

But experts have warned a reliance on the over-the-counter protein powders is fast emerging as a new type of eating disorder.

They said as with anorexia, bulimia and other recognised eating disorders, men are using the supplements to replace meals, while others have been warned to cut down by doctors.

Protein is key to building and maintaining all types of body tissue, including muscle. It contains amino acids, the building blocks used for muscle growth.

Experts in California warned their research has shown a reliance on protein powders and workout supplements such as whey protein and creatine is 'becoming a new eating disorder'

And the claims made by manufacturers of increasingly popular protein products are numerous.

They include helping to boost the body's muscle growth, aid metabolism (helping with weight loss), help users reach peak physical performance, boost energy and fight the ageing process.

'Users may choose to take them before, during and after training to enhance performance and improve recovery, add them to meals to boost their protein or drink them between meals as a high-protein snack,' says Azmina Govindji from the British Dietetic Association told NHS Choices.

'And although protein shakes are convenient, not all of them are suitable to be used as a meal replacement, because they don't have all the vitamins and nutrients that a balanced meal would contain.'

There is also evidence that, in the long term, consuming too much protein can lead to an increased risk of osteoporosis and can also create liver and kidney problems.

In the new study, Dr Richard Achiro, from Alliant International University in Los Angeles, said the risky misuse of legal workout supplements is down to a number of factors.

Body dissatisfaction, low self-esteem and gender role conflict, where an individual perceives he is not living up to the strict limitations of masculinity dictated by modern culture, all play their part, he said.

Body dissatisfaction, low self-esteem and gender role conflict, are in part to blame for the increasing tendency of men to use the supplements

He said: 'Body-conscious men who are driven by psychological factors to attain a level of physical or masculine 'perfection' are prone to use these supplements and drugs in a manner that is excessive and which was demonstrated in this study to be a variant of disordered eating.

'As legal supplements become increasingly prevalent around the globe, it is all the more important to assess and treat the psychological causes and effects of excessive use of these drugs and supplements.'

He added: 'These products have become an almost ubiquitous fixture in the pantries of young men across the country and can seemingly be purchased anywhere and everywhere - from grocery stores to college book stores.

'The marketing efforts, which are tailored to addressing underlying insecurities associated with masculinity, position these products perfectly as a 'solution' by which to fill a void felt by so many men in our culture.'

Researchers recruited 195 men, aged 18 to 65, to take part in the study.

They had all consumed legal appearance or performance-enhancing supplements, for example whey protein, creatine or L-cartinine, in the past 30 days.

And they all told researchers they work out for fitness or appearance-related reasons at least twice a week.

Participants completed an online survey asking questions about a variety of subjects, including supplement use, self-esteem, body image, eating habits and gender role conflicts.

Dr Achiro and co-author Peter Theodore found more than 40 per cent of the men taking part indicated their use of supplements had increased over time.

Twenty-two per cent said they replaced regular meals with dietary supplements that are not intended to be meal replacements.

But most alarming, Dr Achiro said, was that 29 per cent of people said they were concerned about their own use of supplements.

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At the more extreme end of the spectrum, eight per cent of participants indicated that their doctor had told them to cut back on, or stop using the supplements because of possible adverse side effects.

And three per cent had been hospitalised for kidney or liver problems that were related to the use of supplements.

Dr Achiro and Dr Theodore developed the scale by which participants judged their use of the supplements.

It was found to correlate to well-established diagnostic indicators of an eating disorder, such as eating concern and restrictive eating.

'The most critical implication for these findings is to put risky/excessive legal supplement use on the map as an issue facing a significant number of men,' said Dr Achiro.

The research was at the American Psychological Association's annual convention.