Protein powders decoded: why and when you should consume protein
Protein promotes faster muscle rebuilding after a high-intensity or long workout – which tears down muscle tissue. The combination of fast-acting whey and slow-release casein found in milk prevent muscle breakdown, particularly during fasting windows, which is why it tends to be used overnight. The general counsel is to consume protein up to one hour after a workout – particularly resistance training – to induce muscle hypertrophy (read: muscle growth).
Powder v food
While many dietetic experts favour wholefood protein sources, protein powder prevails in the convenience stakes. It also beats high-fat protein sources such as fatty meat.
"For trainers who don't have time to prepare wholefood meals on the run or immediately after exercise, a protein shake may be preferred for practical as well as performance reasons," says Fighting Fit PT Sara Kratz.
Protein powders typically include a combination of carbohydrates and fats in ratios varying from 90 per cent protein to a 50-50 split of protein and carbohydrates. The shake format can, however, make it easy to overshoot caloric needs as unlike with food, there's no visual portion cues.
Pre- and post-workout
Best Protein: Whey protein
Look for: 100 per cent whey protein isolate and whey protein concentrate blend post- and pre-workout (24 g protein per serve).
How much and when?: Mansfield recommends a serve of protein pre- and post-workout. Pre-workout, "the protein shake will help preserve muscle breakdown and provide a small amount of energy. Post-workout, consume a whey-based protein immediately, as it is critical after exercising that your muscles rebuild and repair themselves." For ultimate results in building muscle, Mansfield advises "to have a casein protein shake or meal replacement shake at bed time".
kJ guide: 925
Best Protein: A low-protein blend of soy isolate and whey protein is optimal for fat burning according to Mansfield.
Look for: Some powders may also have added ingredients that claim to aid fat burning and support metabolism – think green tea and acai, although it's difficult to gauge whether ingredients shown to be effective in isolation increase the efficacy of host products.
How much and when?: "The best time to have a protein drink is within 30 minutes of finishing exercise like a full-body workout or weights," Hunter says. "If it is an easy walk, it is best just to go for a wholefood snack or just eat your next scheduled meal if it is within the next hour or so."
kJ guide: 480
Meal replacement/Weight Loss
Best Protein: Whey-based protein.
Why?: "Weight loss is one of the most popular reasons for using of protein powder, even being used as total meal replacement shakes. Proteins have a 'thermic' effect, meaning they create heat in the body through the process of digestion. Since proteins take a lot of energy to digest, you burn more calories after eating a meal high in protein," says Mansfield.
Look for: Both protein and carbohydrate content over the type of protein, says Hunter. Many pharmacy programs sell off-the-shelf DIY-style VLCDs (fewer than 800 calories), but many cheaper programs' products are high in sugar, so check the labels. Look for a product higher in protein and fibre and lower in carbohydrate and sugars.
How much and when?: Whey-based, low carbohydrate (3g), high protein (20g), Mansfield advises.
kJ guide: 504
Best Protein: 100 per cent whey-based protein
Why?: According to nutritionist Zoe Bingley-Pullin, whey is the Swiss Army knife of protein. "The great thing about whey-based proteins is they are not just a meal replacement, they are great as part of your everyday eating plan, and a great way to add some extra protein into your meals," she says. A fringe benefit is that protein powder can lower the glycaemic index of a meal, leading to greater satiety.
Look for: "Read the label and look out for synthetic sweeteners and emulsifiers, which are often added to protein powders. You want a high-quality protein which is both healthy and delicious and provides you with everything you need."
How much and when?: "We should be consuming one gram of protein for every kilogram of body weight. For example, a 70 kg female would require 70 g of protein a day," says Bingley-Pullin. "Taking into consideration that you are consuming a healthy and balanced diet, containing protein and other nutrients, you should aim for 25 to 50 g of protein per serve of protein powder."
kJ guide: 670.
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