It's a no brainer - athletes that train heavily need more protein than sedentary people; but how much do they really need?
The Australian Institute of Sport has published guidelines for evidence-based supplementation for athletes in training. This information is a useful resource for anyone who engages in moderate to intense physical exercise.
Evidence suggests there is no benefit of eating more than 0.3g protein per kg of body weight, per meal. For a 70kg adult, this equates to an upper limit of around 20g of protein per meal. However, the recommended protein intake is 1.2 - 1.6g per kg of body weight, per day. For a 70kg person, this equates to around 100g protein per day!
The only way for athletes in training to get enough daily protein is to spread out their protein intake with several meals (or supplements) per day to meet the daily requirement. For a 70kg adult: 20g per serving, with 5 servings spread throughout the day would meet the general requirement. There is no benefit from taking this protein all at once.
In other words, adding 30g of whey protein isolate to supplement your evening steak is of benefit.
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