In recent years there’s been a growing awareness of the role of protein in the diet, especially for weight loss, but also for increasing or maintaining muscle mass. No longer the sole preserve of body builders, commercial protein supplement powders and bars are filling shelves in supermarkets, pharmacies and health food stores. But do you really need a special supplement, or would a healthy diet suffice?
In this article we look at the protein needs of the three main groups targeted by protein supplement marketing, and weigh up whether they're necessary, helpful or a waste of money. These groups are:
Protein supplements are often promoted for athletes – from your average gym junkie to professionals and elite level athletes. While it’s true athletes have higher protein needs than more-sedentary people, whether they really need a supplement is debatable. Protein is said to have several key benefits for athletes: providing speed and stamina, aiding recovery and building muscle.
Athletes attempting to gain muscle size and power need more protein at the beginning of an intensive strength-training program, but the muscles adapt to the new regime and subsequently less protein is required so that they only need slightly more than a typical active person. And because people who exercise heavily tend to have a greater appetite, their protein requirements are generally met without the need for a special high-protein diet or supplements – even body builders.
Some pre-workout protein supplements claim to help increase speed and stamina, but is there any evidence for this? A 2010 review of studies found that consuming protein before or during exercise doesn’t help people go faster, but it does help with endurance. However, in studies that found this, the protein drink contained more kilojoules than the drinks it was compared with, so it could have been the extra energy rather than the protein that made the difference. More studies comparing preparations with similar energy value are needed.
After training or competing, athletes need to refuel, rehydrate and repair muscle. This is particularly important for athletes who need to perform again soon after, but it also helps alleviate muscle soreness after a hard workout. Sweetened liquid protein drinks are ideal because the carbohydrate helps restore glycogen to muscles, the liquid helps rehydrate and the protein helps prevent muscle tissue breakdown and stimulates muscle tissue synthesis, which is further assisted by the insulin resulting from the carbohydrate.
Timing and amount
The optimal amount of protein for a post-workout snack is thought to be about 20 grams (g) of high-quality protein (from meat, eggs and dairy) – any more than this will not be used. Protein supplements marketed for post-exercise recovery may contain the required elements, but there's a growing body of evidence in favour of flavoured low-fat milk, which has protein, fluid, electrolytes and carbohydrate, and is cheap, effective and readily available. Whey protein found in milk is considered an ideal choice because it's high an important muscle-building amino acid called leucine, and is digested quickly so it’s available when muscle tissue synthesis is at its peak. Flavoured yoghurt, smoothies and breakfast cereal with milk are also recommended. However, protein supplement drinks and bars may be a convenient alternative for some people – they can be kept in a gym bag, or taken when travelling for example.
There’s a large body of evidence showing that consuming protein immediately after training (within an hour) enhances muscles' uptake of amino acids from the protein, and therefore maximum benefit can be gained. However, muscle repair continues for 24 hours so regular consumption of protein thereafter is also important.
Commercial protein supplements (drink powders and bars) may be a convenient source of protein to have on hand post-workout for serious athletes, but aren't necessary for recreational athletes who are likely to get plenty of protein from their normal diet. They may be also be more expensive per gram of protein than other sources such as milk, eggs or meat, and depending upon how they’re used may provide more protein than can be usefully used by the body.
Protein for weight loss
Another major target for protein supplements are people trying to lose weight. Visit a pharmacy, health food store or supermarket and you’ll find a huge range of protein powders, bars and snacks aimed at people trying to lose weight. Increasing the amount of protein in the diet can help with weight loss and maintenance of weight loss because it keeps you feeling fuller and less hungry for longer, and kilojoule for kilojoule it requires more energy than fat or carbohydrate to process and store in the body. Having adequate protein when reducing kilojoule intake also helps reduce the loss of muscle mass, especially when combined with resistance training, and this also contributes to weight control because muscle tissue consumes energy.
But do you need special supplements?
According to Dr Rosemary Stanton, when it comes to weight loss, the evidence is really only that kilojoules count. However, she acknowledges, “Some people have found it easier to reduce their kilojoule intake by omitting foods high in carbohydrate or fat – and that leaves protein.” With concerns raised by some studies about the long-term effects of a diet high in red meat, protein shakes, snacks and supplements have been marketed as a better source of protein than red meat. Stanton argues, though, “that this is an expensive way to get extra protein and with no evidence that such diets are of any special benefit for long-term weight loss, it seems a fairly useless exercise.”
Most Australians get plenty of protein in their diet and don’t need protein supplements to achieve weight loss. A diet featuring vegetables, fruit, whole grains, low-fat dairy and lean protein is consistently linked with successful weight control. For snacking, try replacing high sugar and/or high-fat manufactured snack foods with whole foods such as low-fat plain yoghurt, a handful of nuts and seeds or a hard boiled egg.