Amanda's Wellbeing Podcast - Protein Intake & Amateur Athletes

In today's episode, I look at protein requirements for amateur athletes (i.e. active people) and explain why they need more protein than sedentary people. I also discuss the best types of protein-containing foods to consume and when to do so for enhanced muscle protein synthesis.

Transcript

Hello and welcome to Amanda's wellbeing podcast, Five Minute Food Facts series. I'm Amanda Hayes, Your host, A lawyer turned nutritionist with a passion for wellbeing. I decided to do this series because there is so much conflicting information available about food and various diets. Some of it is credible and some of it is not. It can be time consuming, Not to mention confusing to try and sift through the noise and get to the heart of the matter. In this series, I will do all of that for you and present factual, Reliable information in a concise and easy to understand way. The content of my Five Minute Food Facts series is for information purposes only and is not a substitute for advice from your own health professional. Today I will be talking about protein intake and athletes. This will be the second of a four part series I'm doing all about protein. The first episode was an overview of protein, What it is and why we need to eat it. Today I'll look at protein intake and athletes, As I said. The next episode will be about protein intake on a plant-based diet. And finally, I'll talk about protein intake and people over 40 and the role of protein in healing from injury and trauma. I'll quickly apologise upfront because this episode will be significantly longer than five minutes. There is so much information available, It's been quite difficult to cut it down and honestly, You could write a book about it. Anyway, I'll dive deeper into the protein requirements for athletes and by athletes I mean active amateur athletes, Not professional athletes because they most likely have access to a sports dietitian. So my interest in this area stems from personal experience. I am by no means a talented athlete, But I do do a lot of training, Often in excess of 10 hours a week. Since my 20s on and off I've followed a vegetarian diet because there are so many things about this way of eating that I'm attracted to. Every time I've come unstuck at some point with either low iron or fatigue. Anyway, For about the last seven years I ate mainly a vegetarian diet with some fish. With my nutritional knowledge I thought this time I have the skills to get this right and do it successfully, Which I maybe didn't have the last few times I tried to eat in a vegetarian way. So to cut the story short, Even though I thought I was doing all the right things and eating adequate protein from mainly plant-based sources, I came up again against the same problems. I had low iron, Not a frank deficiency and extreme fatigue. So on the advice of several health practitioners, I introduced some animal protein into my diet. I struggled a bit to do this because I really didn't want to and there are so many examples of people out there who can manage, Like my idle rich role, So why couldn't I? What was wrong with me? But at the end of the day I did take their advice, I introduce a bit of animal protein and as reluctant as I am to admit it, I do feel a lot better. I am less exhausted and I feel stronger. So the way I have made peace with it is to still follow a mainly plant-based diet and to eat meat sometimes. To recap from episode 1, According to the National Health and Medical Research Council, The recommended dietary intake of protein for men ages 19 to 70 is 0. 84 grams per kilogram of body weight and for women it is 0. 75 grams per kilogram of body weight per day. So for a 60 kilogram woman this would be about 45 grams per day of protein. The amount is greater for children, Adolescents, Pregnant and lactating women due to growth requirements. The first question is, Do athletes need more protein and if so, Why? So historically it was believed that because muscles are made up of protein, High dietary protein intakes were required to maximise muscle growth and it's easy to understand how this belief was arrived at. As the role of carbohydrate and fat oxidation in muscle metabolism became increasingly understood, The intense focus on protein waned but now I would say protein is centre stage again. So exercise breaks down protein, People doing high amounts of exercise need more protein than sedentary people just to prevent the loss of muscle tissue. It's widely accepted that consuming protein post-workout induces a significant rise in muscle protein synthesis and it helps recovery. Therefore this is another reason athletes do require more protein than the average person. However like so many things in nutrition, How much they need is not a clear cut issue and it depends as you can imagine on many factors such as how much an athlete eats in the first place, The duration and intensity of the exercise they do, Their training status, Their body size, Their gender and their age. So the range is from 1. 2 to 2 grams per kilogram per day and as you can see that is higher than the 0. 84 and 0. 75 recommended for men and women respectively. So the next thing to look at is the difference between strength or resistance athletes like weightlifters and endurance athletes. If we look at the strength athletes first, After resistance training there is an upregulation that means increase of muscle protein synthesis with an increased sensitivity to dietary protein. So that is why the timing of protein is important. To maximise the adaption to training it should be consumed within a two hour period post training. For strength athletes research also supports protein ingestion pre-workout as beneficial but I won't go into that here. Scientific studies looking at the dose response of high quality protein intake post exercise have shown that between 15 to 25 grams of protein, Depending obviously on the size of the athlete, Is sufficient to elicit a maximal response in muscle synthesis. So in this case more is not necessarily better. Protein ingested in excess of that amount that can't be utilised is oxidised rather than used in muscle synthesis. Scientific evidence also shows that adding carbohydrate to post exercise snacks enhances the effect of muscle synthesis and the reason for this is because leucine which is an essential amino acid and found in whey protein can help promote maximum protein synthesis. But in order to do so it requires the presence of insulin and carbohydrate is the macronutrient that causes the body to release insulin. Therefore an ideal snack contains both protein and carbohydrate. Then if we have a quick look at endurance athletes, To date most research has been done in relation to strength athletes as these are the ones that are trying to bulk up their muscles. So it's interesting to look at endurance athletes for example distance runners, Triathletes, Cyclists or cross country skiers. During endurance exercise the majority of energy is derived from the oxidation or burning of carbohydrate and fat and a much smaller proportion from protein oxidation. And of this it's mainly the amino acid leucine that is oxidised. And the more you use up your carbohydrate or glycogen stores the more that leucine is oxidised. So generally sports dietitians recommend endurance athletes aim for 1. 4 to 1. 6 grams per kilogram of body weight of protein per day. One recently published study looked at the dose response effects of dietary protein on muscle protein synthesis during recovery from endurance exercise in young male athletes. And actually I think that's important, The study group here. Without going into details of the study the findings included that protein ingested after endurance exercise was efficiently digested and absorbed. There was a dose response relationship in relation to whole body net protein balance, So that means the more protein they ate up to a point stimulated more protein synthesis. And they also found that 30 grams of high quality protein is enough to maximise skeletal muscle myofibrillar protein synthesis rates, That is the synthesis of contractile proteins and really think strength there. But as I mentioned these were trained endurance athletes and it's probably more useful to look at the amount of protein per kilogram of body weight than a set number. A small frame woman would obviously need less than a tall male athlete. I think what's important to note here is that protein intake post exercise is important for both resistance and endurance athletes and the best results come if that post exercise snack also contains carbohydrates. So that's probably the message at the end of the day. Causes of protein. Milk based proteins have been widely studied and are effective in increasing muscle strength and promoting favourable changes in body composition. The reason for this is that they are well digested and absorbed due to their leucine content. And milk also contains carbohydrates so you're getting a good combination to promote optimal recovery plus importantly it's inexpensive. I'll just note that in the endurance world there is quite a lot of focus on carbohydrates so it's interesting to know that the consumption of carbohydrate and protein together produces better improvements in performance than consumption of carbohydrate alone post workout. Milk protein is made up of 80% casein and 20% whey. Whey is highly soluble and absorbed quickly and casein is absorbed more slowly. Examples of good milk based recovery snacks include chocolate milk, A smoothie or Greek yogurt with fruit. However some people are lactose intolerant, They don't like cow's milk or they follow a vegan diet so soy protein is another high quality protein that is a good option so a soy milk based smoothie for example. Other examples of good recovery snacks that are dairy free could include a whole wheat tuna and salad sandwich, Whole wheat bread with peanut butter and banana or a handful of almonds and an apple. And if whole foods are not available so for example if you're at a trail race in a remote place you obviously don't want to leave a carton of milk festering in your car for 6 hours so protein supplements and powders can certainly have a role to play in those situations. And now for a note on the timing of your post exercise snack including protein and hopefully carbohydrate as well, The generally accepted window is within 2 hours after exercise. Although many scientific studies look at the timing of protein intake and timing can and does have an impact, It is actually important not to lose sight of the fact that the most important contributor to protein synthesis or muscle adaption is of course training that is stimulating the muscles and when it comes to dietary roles, Protein intake over the long term is the crucial factor. Ideally moderate amounts of high quality protein should be spread across the day so don't worry if you don't nail your post exercise snack every time. And now I think we can't talk about protein and athletes without mentioning food versus supplements because athletes are always striving for optimal performance it can make them susceptible to marketing claims about some protein and amino acid supplements. In 2015 protein powder sales were valued at $4. 7 billion in the US. To be honest I was shocked when I saw that figure, That's massive. So I'll just make a few quick observations here, Whole food is almost always a better option than supplements because protein when it's found in whole foods is bound up with other nutrients like vitamins and minerals. So if you replace food with supplements you might miss out on some of these other crucial nutrients. Also you should be cautious about taking single amino acids at levels significantly higher than found in normal food because this is just not what the body is used to. Supplements are expensive especially if you end up consuming excess protein that the body doesn't utilise for muscle growth. And just a quick note about branch chain amino acids like leucine. Branch chain amino acid refers to the molecular structure of the amino acid molecule by the way. So there are many claims about the amazing effects of branch chain amino acids on muscle synthesis, Decreased soreness etc. Yet the evidence in well controlled human studies is often weak or lacking. Leucine does stimulate the pathway, Called the mTOR pathway that turns on muscle protein synthesis. But this is only one step in a chain of necessary processes. And if the branch chain amino acids consumed on their own without the other essential amino acids, Muscle protein synthesis is not enhanced as all the essential amino acids are necessary for new proteins to be made as I referred to in episode 1 of this series. And just to wrap all that information up. Recreational athletes like many of us eating a balanced diet are more than likely consuming adequate protein. Athletes need to ensure that, In addition to protein, They are consuming adequate carbohydrate and fat as it is the synergistic effect of eating all the macronutrients that has the best overall effect. Protein consumption is best spread throughout the day. And post exercise for both resistance and endurance, Take on a snack that combines protein – 15-30 grams depending on your body size, The length and intensity of your exercise bout and carbohydrate for the best adaptive response. I do hope that was useful. I did find it quite a challenge to try and summarise all the information because there is a lot out there. Thank you very much for listening to my podcast today and I hope you have a wonderful day. Eat well, Move well, Think well.

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