Updated: Jan 29, 2019
With companies keen on selling you their protein powders and protein shakes, it is often difficult to know if nutrition advice on the internet is grounded in solid research or is just a ploy to get more sales.
The advice provided by popular magazines like Men’s Health have also been shown to often be pseudo-science. They cherry pick results that sound more exciting (why let the facts spoil a good headline?) or to support what the author wants you to believe, instead of presenting a balanced view of the benefits of protein supplements.
In this article I'll discuss what the current research says about:
How much protein is needed after exercise to best stimulate muscle growth?
Is there any benefit in taking protein supplements during exercise?
Is there a “best time” to ingest protein to help build muscle?
What is the best source of protein for athletes?
Should high-protein diets be consumed when trying to lose weight?
When recovering from injury, can a high-protein diet prevent loss of muscle mass?
Protein intake and your immune system
Are protein supplements better than food sources of protein?
DISCLAIMER: I do not sell, endorse or even use any protein shakes, powders or other protein supplements and hope that this article provides a balanced view.
1. How much protein is needed after exercise to best stimulate muscle growth?
We know that exercise is a potent stimulus to build muscle, but this can only happen if you have the right nutrients available. Your muscles first go through a break down phase after exercise and then has to use the proteins that you have eaten during the day to rebuild themselves stronger.
It turns out that the average person only needs about 20 to 25 g of high quality protein after an exercise session, but this should be consumed within 2 hours after exercise to get the most benefit. If you are classed as a masters athlete (above 50 years of age) you may have to take on higher doses of protein to allow your muscles to recover at the same rate as your younger self.
This does not have to be in the form of a protein shake or bar. It can simply be whatever protein you are eating with your next meal (see the list below for natural protein sources). This is good news for me since I really struggle with consuming anything with the word "supplement" in it – I think my brain files it in the same category as medicine ☺.
The more the better, right? Well, actually no. Research has not found any extra benefit if you take greater amounts of protein supplements within that period of time (see the following section for more details on how to use protein supplements throughout the day).
Endurance athletes may be interested to know that protein intake after exercise can also help to increase mitochondrial proteins. Your mitochondria can be seen as the battery boxes of your cells. Eating enough protein after exercise may allow your muscles to become better at using the oxygen that is available to them during your next exercise bout.
Foods and Beverages Providing 20 g of High-Quality Protein
You can check the protein content of different food sources on the USDA website. I've calculated the most obvious ones below.
Fluid 1% low-fat milk (plain or flavoured) - 591ml
Low-fat yogurt (plain) - 454g
Low-fat Greek style yogurt (plain) - 227g
Soy milk, plain - 680ml
Lean beef or pork - 85g
Lean ground beef patty - 85g
Poultry - 85g
Eggs, whole - 3 large
Eggs, white - 6 large
Cheese, cheddar - 85g
Cheese, low-fat string cheese - 85g
Cottage cheese - 43g
Tuna, light canned in water - 85g
Salmon, farm-raised - 85g
Broadbeans (raw) - 80g
Red Kidney beans (raw) - 80g
Lentils (raw) - 85g
2. Is there any benefit in taking protein supplements during exercise?
Not unless you are an endurance athlete! Research has shown that athletes are unlikely to experience performance benefits from consuming protein during events, but that they may recover better if they consume protein during events that are longer than 3 to 5 hours.
Ultra-endurance athletes may be less able to digest and absorb protein after exercise of this duration, because of the blood being shunted away from the gut to the muscles. Taking on some protein during endurance events can help them reach the optimal levels within the right time frame and may thus hold an advantage for their recovery, especially in multi-day events.
Protein supplements may be a better choice in these situations, because they are easier to digest.
3. Is there a “best time” to ingest protein to help build muscle?
The current research seems to suggest that the average person should aim to consume about 30 g of high-quality protein in 5 small meals (or if you're not average size 2.5 g/kg bodyweight divided into 5), spaced evenly throughout the day to get the most benefit. Researchers also found that consuming an additional 40 g of protein before bedtime allows your body to continue building muscle while you sleep.
If you are over the age of 55, you may have to follow a slightly different approach. Older athletes require more protein and should take it at different times to get the same benefits as younger athletes.
4. What is the best source of protein for athletes?
When you eat protein, your stomach and gut breaks it down into various amino acids (the basic building blocks of protein). Your body then uses these amino acids to rebuild your own muscle proteins.
So it makes sense that the best protein to eat is protein that provides all of the essential amino acids. The research has shown that milk protein may have the advantage over single source proteins, like soy, because milk contains both whey and casein. Whey protein appears to be more effective than casein alone and soy is slightly less effective than whey.
Whey protein’s superior effect is thought to be due to it containing the amino acid Leucine (1.8g of Leucine post exercise appears to give the best results). Do take care when you buy whey protein, since not all preparations contain the same amount of protein.
Milk may be a cheaper and better option, since 600ml of the white liquid not only contains 20g of protein (whey and casein) and plenty of leucine, but also other vitamins and minerals that the body needs.
5. Should high-protein diets be consumed when trying to lose weight?
The short answer is yes, but as usual it is a bit more complicated than that. It may really be worth discussing your diet and exercise volume with a dietitian to get the best results.
If you want to preserve your lean muscle mass while enhancing fat loss, the research currently suggests the following recipe:
A 500 calorie deficit per day. This means that you should work out how many calories you burn through your exercises etc. in a day and your total intake should be 500 less.
Eat 1.8 to 2.7g/kg/bodyweight of protein per day (or at the higher end of the Acceptable Macronutrient Distribution range of 30% to 35%).
30% of your calories should come from fat and the remainder from carbohydrates (total calories – calories from protein – calories from fat = how much carbs you should eat).
And finally, combine this diet with resistance training.
6. When recovering from injury, can a high-protein diet prevent loss of muscle mass?
Remember that you need a combination of exercise and enough protein in your diet to gain muscle mass.
Exercise + Protein = More Muscle
This unfortunately means that you will lose muscle mass if you cannot exercise that muscle, despite eating adequate amounts of protein. You may be worried about getting fat when you can’t train and restrict your calories during injury. Your body can, however, only repair if you actually provide it with all the nutrients it requires to get the job done.
While consuming protein will not stop you from losing muscle, it still plays an important role in your healing and recovery. The research suggests that you should aim for 1.6 to 2.5g protein/kg bodyweight, spaced evenly throughout 4 to 6 feedings a day.
And all is not lost! There may be a way of getting the "exercise" component in without causing further harm. Neuromuscular electrical stimulation (NMES) is a very effective tool that we use in practice to exercise muscles when the joints, ligaments or tendons do not allow us to do traditional strength training. We use the Compex machines in our clinic. They are small and portable and stimulate strong muscle contractions that produces the same results as you get from lifting heavy weights, but with no pressure or force in the joints or ligaments.
If you are worried about losing muscle mass while injured, my advice would be to eat adequate amounts of protein and get a Compex machine to exercise the muscles around your injured body part. Also continue your strength training programme for the rest of the body as normal.
7. Protein intake and your immune system
A high protein diet (3 g/kg body weight per day) in atheletes has been shown to help restore their immune systems after training. Athletes who undergo high volumes/intense training programmes reported fewer upper respiratory illnesses (headcolds, coughs and sinus infections) when they ate high amounts of protein during the day.
8. Are protein supplements better than food sources of protein?
There is no evidence that protein supplements are superior to food sources.
Using protein powders and bars may be more convenient than lugging food around, but it is important to realise that protein supplements are not policed by any quality commission. As a result these products have been shown to:
Sometimes not contain the active ingredients stated on the label;
May contain harmful substances including toxic agents and prescription-only pharmaceuticals;
Another advantage of eating regular food proteins is that they also contain other essential nutrients that aren't present in supplements. Eggs, for instance, contain Vitamin D which has been shown to be essential for healthy bones and muscles.
My advice would be to eat whole foods most of the time and buy your protein supplements, shakes and bars from reputable brands.
Let me know if you have any questions. Need more help with an injury? You can consult me online using Skype video calls. Feel free to join my Facebook group where you can watch livestreams on different training and injury related topics.