They are sold as a magic bullet for building up muscle, but are protein powders and bars a waste of your money?
Lunchtime for John Davis, a risk management executive at Colonial Asset Management, is often a run from Sydney's Martin Place across the Harbour Bridge to Balls Head, near Waverton.
All up he covers a 14 kilometre City-to-Surf distance within an hour because he finds that the exercise clears his brain, making the afternoon in the office more productive.
Although he is "seriously sceptical" about the claims from companies that make protein supplements, he concedes that they do have a certain convenience factor for fuelling his fitness activities.
“I can't sit all day at my desk eating after I have exercised, so I eat a sensible lunch then follow it with a protein bar or shake", he said.
“I do see guys who take protein shakes two or three times a day, which I don't see the benefit in. But I have seen the difference between snacking on protein and eating something like a chocolate bar, which gives you a sugar hit then a deflated feeling afterwards".
Pam Stone, a naturopath for natural health company Blackmores, said protein supplements were one of the fastest growing sectors in the health market.
Last year, according to sales data collection agency AZTEC, Australians spent $80 million on sport food, an increase of 27.7 per cent on 2011.
Even so, fitness experts advise consumers to venture cautiously.
Dr Louise Burke, the head of sports nutrition at the Australian Institute of Sport (AIS), said that while protein supplements were an everlasting favourite in sports nutrition, many people were wasting their money in the types they chose and the way they took them.
“Everybody who goes to the gym these days thinks they need an ultra expensive super-scientific sounding protein supplement but it's often unwarranted" Burke said.
"You can get great amounts and types of enough protein from regular food and this would save you money. High quality protein can be easily found in animal sources such as dairy products, eggs and meats.
"There is no doubt recovery after a weights or cardio session is improved if you consume good quality protein within an hour of working out. But the benefits top out at a dose of about 20-25 grams of protein."
Protein supplements were more beneficial when used as convenience products, she said.
"They are practical and convenient in that you don't have to refrigerate them and shakes are easy to take. But my advice is that if you are buying them, go for either a simply whey protein powder without any other fancy ingredients, or if refuelling is also important, choose a liquid meal supplement with carbohydrates as well as the protein."
Nutritionist Joanna McMillan agreed, saying many male athletes overused protein supplements.
“There is a place for whey protein supplements immediately before or in the half hour window after strength training,” McMillan said.
“Otherwise they are completely overused by most men. They drink them at all times of day as if they will magically build muscle. It's crazy.
“At the end of the day protein supplements are a processed food product and many of the ridiculous claims made on the ones with a whole load of extras added have no scientific backing. Often a glass of milk would be just as good.”
So what's the science behind protein diets and muscle?
The AIS recommends consuming protein soon after exercise to provide building blocks that can take advantage of the increased rates of muscle protein synthesis for up to 24 hours after a workout. When carbohydrate is needed for refuelling, or additional energy for maximum weight gain, this protein can be combined into choices such as flavoured yoghurt and milk, fruit smoothies, liquid meal supplements such as Sustagen Sport, sandwiches, cereal and milk and sports bars. “
Marathon trainer Sean Williams, who trains runners at Sweat Sydney, said protein supplements were most popular among those wanting to bulk up.
“These supplements are very popular in bulking diets as they help your muscles grow,” Williams said.
“It is not the actual protein in these supplements, often coming from a food like whey, which will increase your weight. It is the total number of calories in the supplement. The problem is that the supplements are often loaded with piles of sugar.
“It is great to take protein mixed with carbs immediately after a run to aid in a fast recovery. But I recommend runners do it the natural way in the form of a fruit smoothie. If your diet is low in protein then some extra protein is not going to hurt and will probably help your metabolism.
But for runners who don't want to increase muscle bulk or weight, he warned supplements may actually handicap performance, in much the same way a race horse is handicapped with extra weight.”
So how much protein does a person need?
According to the AIS, recreational endurance athletes who exercise four to five times a week for 30 minutes need 1.2 grams of protein per kilogram of body weight a day. So a 75 kilogram man would need to consume about 90 grams of protein a day. But the important message is not just how much you consume, but the way you consume it.
The best idea, the AIS said, was to consume some just after exercise, and to spread the rest out over meals and snacks during the day. This is different to our typical patterns where we eat enough over the day in total, but most of it is consumed in the evening meal.
Professor Ingo Froboese, from the Centre for Health at the German Sport University in Cologne, said that anyone consuming more than 0.8 and 1 gram of protein per kilogram of body weight could be damaging their metabolism, which can affect the kidneys.
“The best thing to do is to eat a balanced diet. Ordinary food will have enough protein in it,” Professor Froboese said.
Ray Klerck, a fitness writer for Men's Health magazine, claims the best option is to buy cheaper no-name whey protein, add a banana and berries and a couple of egg whites.
“So many protein supplements have many additives, sugar and preservatives to add a point of difference,” Klerck says.
“You don't need them. It's important to eat 30 grams of protein before and after exercise – both cardio and weight training – as protein helps your muscles build size and strength and hormone changes after exercise mean after a workout is the time when the body can absorb the most protein.”
Estimated protein requirements (g/kg/day)
Sedentary men and women - 0.8-1.0
Elite male endurance athletes - 1.6
Moderate-intensity endurance athletes (exercising about four to five times a week for 45-60 min) - 1.2
Recreational endurance athletes (exercising four to five times a week for 30 min) - 0.8-1.0
Football, power sports - 1.4-1.7
Resistance athletes (early training) - 1.5-1.7
Resistance athletes (steady state) -1.0-1.2
(Female athletes - 15% lower than male athletes)
Source: Burke and Deakin, Clinical Sports Nutrition