We are a nation of gym junkies and thanks to our collective pursuit of leaner bods and bigger muscles the protein supplement market is booming.

The Australian nutrient product market is estimated at $805 million, with protein bars accounting for $105 million.

Globally, the whey protein – one of the most effective forms of protein for muscle building – market is projected to reach $US9 billion by 2022.

The trouble is that most people get more than enough protein from whole food sources like milk, meat, soy products and eggs as part of a normal, healthy diet.

For the average gym-goer who hits the weights room once or twice a week, protein powder is at best superfluous and at worst a health risk.

More than enough

Associate Professor Tim Crowe from the School of Exercise and Nutrition Sciences at Deakin University says there’s no doubt the combination of strength training and sufficient protein stimulates muscle growth.

But, because most people eat enough whole food sources of protein to fuel even an athlete’s training schedule, protein powders are usually unnecessary.

“The recommended amount is about 1.2g of protein for every kilo of body weight,” he says.

“The average Australian diet already gives that and even that’s recommended for athletes not just regular gym-goers who need much less.

“Protein powders promise additional benefits that potentially your diet won’t be able to give you, but that’s completely false.”

Gabrielle Maston, an accredited practising dietitian and spokesperson for the Dietitians Association of Australia, says the only exception may be people undertaking intensive training for more than one hour per day on five or more days per week.

“If someone is doing a lot of weight training or really high-intensity athletic training, that may warrant the use of protein powder,” she says.

“But if you’re just turning up to the gym and doing regular aerobic classes and occasionally lifting weights you will get enough protein out of your diet from following the healthy guidelines – having a few pieces of animal products during the day and your servings of dairy, or vegetarian alternatives.”

The high-protein diet

Protein can aid weight loss because it improves satiety, requires more energy than fat or carbohydrate to process and store in the body, and helps reduce the loss of muscle mass, which burns fat.

Indeed, studies have shown that a high-protein, low-GI carbohydrate-based diet is one of the most effective for weight loss.

However, Ms Maston says protein bars and shakes are often higher in calories than whole food sources of the nutrient, which can have the opposite effect on weight-loss efforts – especially if you’re consuming too many.

“I’ve seen it happen – people have a lot of the powder, two to three scoops in each shake several times day, then wonder why they start to put on body fat,” she says.

“So it’s not just about building muscle but also keeping your energy intake matching what you’re expending in terms of your exercise levels.”

The risks

Plus, Ms Maston says low-quality protein powders that haven’t been lab tested may pose health risks.

“Different brands of protein powder have different impurities in them, and we have to be careful using supplements in general because it’s not a regulated industry – it falls within the grey area as it’s not a food or a medicine.

“There have been studies to show that there’s a lot of heavy metal contaminants in some protein powders. If you’re using quite a lot of those supplements you could cause health problems from impurities that are in poor-quality protein powders.”

Ultimately, Associate Professor Crowe says it’s best to concentrate your efforts on clocking up more time in the gym – which, unlike protein consumption, is an area where most Australians are lacking.

“The biggest thing people should focus on is working harder in the gym to get that muscle growth in the first place,” he says.