Welcome to Straight Talk on Health, I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Nutrition. Exercise. Diet. Supplementation. If there’s something new, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
One of the basic tenets in sports nutrition is that we shouldn’t consume more than 25 grams of protein in a drink product. It's not a hard and fast rule but it has been a guide ever since I've been in the exercise physiology arena. It is based on prior research decades ago. The reasoning has been that taking any more won’t help you to add more muscle after a workout. This has trickled down over the years to the point that it applies to anyone who drinks a protein shake. Based on a recent study, that may not necessarily be true. It may be time to reconsider protein intake.
I think that there are at least three reasons why protein intake is important. The obvious in this study is the use of protein to build muscle and possibly, as you will see, to examine whether energy can be produced from amino acid residues. Amino acids are the building blocks of proteins. If they are used to make energy, that may interfere with the muscle building process. But I think there are at least two more reasons. One would be the manufacturer of protein enzymes which catalyze many chemical reactions in the body. Those chemical reactions often result in a manufacture of proteins that have distinct functions in our body such as insulin.
The third reason why I think that protein intake is important is for protein loss in the elderly. You can define elderly as over 50 but when I talk about it, it generally means someone over 70. There seems to be, either a decline in protein intake which has been somewhat verified in research studies, or a decline in the ability to digest protein. The net effect is the loss of muscle mass, also known as sarcopenia. While this research paper deals with sports nutrition and protein utilization, it may have implications that carry over into other areas as well.
First, let’s review why you want to build muscle, regardless of age. Obviously, more muscle helps you do more with your body: lift heavier objects or move your body more easily. Muscle is more dense than fat, so it takes up less space; when you are more muscular you look slimmer as well as more fit. Maybe most important, more muscle burns more calories than fat does; you can use that fact to lose weight or to eat more food.
Researchers wanted to test how long muscle synthesis would continue after an hour-long intense weight training session. The study was simple in design: take 36 young men who were physically active, test their initial exercise capacity, and then subject them to an hour-long weight training session in a laboratory setting. Afterward, in a randomized way, 12 of them got 100 grams of a protein in a drink, another 12 got 25 grams of protein in a similar tasting drink, and the final 12 got a placebo that had no protein.
That’s where the simplicity stopped. The protein had specific quantities of carbon-labelled amino acids including leucine, the amino acid responsible for initiating protein building in muscle. That means the labelled amino acids could be tracked to see where they went. The objective was to monitor whether protein synthesis lasted more than four to six hours, the previous conventional thinking. The other question is whether the excess protein would be broken down and used for making energy.
The short answer is that protein synthesis lasts at least 12 hours (and perhaps longer) at the highest intake, 100 grams. The 25 grams lasted about 6 hours but even no protein still caused some protein synthesis.
This study demonstrated that there seemed to be a dose-response to protein intake after intense exercise; that is, the more protein the person ate, the more muscle synthesis. And it lasted at least 12 hours instead of the prior four to six hours for a lower dose. Also, the excess protein intake wasn’t used to make energy to any great degree as previously thought; that means less strain on the kidneys, because when protein is broken into individual amino acids, the nitrogen group won’t have to be eliminated via the kidneys.
As always, there are more questions to be answered before this study becomes the new normal. The obvious issue is that the subjects were all young men from 18 to 40. They were specifically chosen because they were not chronic exercisers. The results may be different in people who were regularly training with weights or even cardiovascular exercises at a high level. Would the same results happen in women? And would the same result happen in older subjects, such as those in their 50s or 60s?
Next question: would the extra protein be absorbed and used the same way without the intense exercise session? The subjects did four different exercises using the legs and chest with four sets of ten reps, pushing the subjects to failure on the final three sets. Pushing yourself that hard can be challenging and even dangerous without help. Could someone with known cardiovascular disease push themselves as hard without causing a cardiovascular event? Would metabolic diseases such as type 2 diabetes impact how protein was utilized?
I could go on, but you get the point. One study with fewer than 40 young subjects, using testing procedures that will not be easy to duplicate, isn’t a basis for changing protein intake after exercise for everyone.
What does it mean in the real world, the world we live in now? The obvious answer is that it provides a new area of research. I would be most interested in how the use of essential amino acids could impact the protein synthesis in addition to additional protein intake. But can how this can impact you right now.
On the days that you lift weights, add an additional 10 or 25 grams of protein to your post-workout shake. Milk protein was used as the source in this study, but other sources of protein powders would probably obtain the same result. Although some people may argue the point, the composition of protein powders doesn’t vary much, so choose whatever appeals to you.
The men began drinking their shake after they completed the exercise session. I would also recommend drinking extra water for a couple of hours after the shake. Again, these were relatively young men. As we age, we may see a decline in kidney function. Excess nitrogen, a byproduct of breaking down the amino acids, could build up and turn into ammonia and, as you might expect, that would be bad. Try increasing protein for a specific number of weeks and see what happens. Track whether you’re able to increase body weight or add muscle. You can test your 1-Rep Max on the bench or squats if those are the muscle groups you trained.
If you don’t do resistance exercise, you can see how you respond to the additional protein after a long walk or a yoga session. You might feel better with the additional protein.
Nutrition is a constantly changing field. Some basic assumptions that developed can now be reconsidered with better technology to test benefits or pitfalls. While it may take years or even decades before we have answers, what’s really important is how you respond. Adding some additional protein such as 10 or 25 grams to your morning or post-workout shake is not unreasonable to see how it benefits you. All the research in the world still comes down to how it affects you and your unique body. As long as you’re reasonably healthy, you are your own subject.
Just remember: keep track of what you do and find a way to assess the outcome. That’s the only way we ever really know how it affects you. Our time is up so I’m out of here. This is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.
Reference: Cell Reports Medicine https://doi.org/10.1016/j.xcrm.2023.101324
