Protein 101

Let’s start off with the basics. Proteins are essentially a chain (or several chains) of amino acids arranged in a certain structure, which perform a particular function in the body. The sequence of amino acids and the structure they form is defined by our DNA, which acts as the blueprint for the varying types of proteins. Proteins have a wide range of functions in the body. They form the structures of our body such as hair, skin and muscles, send signals around the body in the form of hormones such as insulin, and carry out a range of functional processes (eg. proteins form the enzymes that digest our food).

There are twenty amino acids that are used in the human genetic code, and are often described as the “building blocks” of the body. Of these amino acids, eleven can be produced by the body and are known as “non-essential”. Nine cannot be produced by the body and are only available by eating food sources , known as the “essential” amino acids.

When we eat plant or animal foods that contain protein, the protein chains are digested down into either individual amino acids or small chains (typically 2 or 3 amino acids long) called peptides. These are absorbed from the gut and into the blood, where they can be taken up by various parts of the body. Some peptides may be “biologically active” and play a role in the body beyond just being a source of amino acids, but as yet there’s very little research on “biologically active” peptides and sports performance. Excess protein in the diet (beyond what the body needs for these processes) is used as an energy source – one gram of protein produces about 4 calories.

What does sport science tell us about protein for cyclists?

In the last ten years science has moved forward in leaps and bounds in protein research, and now we have the ability to measure the effect that training (and nutrition) has on muscles. We’ve always known that training brings about beneficial adaptations in the body, after all that’s why we put in the effort. But now we understand what’s actually going on.

The current consensus in scientific circles is that particular muscle proteins are produced in response to exercise. Different types of exercise stimulate different proteins to be produced. These proteins serve different purposes, such as increasing the size and strength of muscle fibres, but some also increase the number and function of mitochondria (which helps you produce more energy from fat, a great thing for endurance performance).

More recently the focus has turned to the interaction between nutrition and training in this process. It’s been shown that eating protein in the period after exercise amplifies the body’s response to that training, so more muscle proteins are built. In particular the presence of the amino acid Leucine in the blood appears to “trigger” the muscle to make more proteins. This effect has been shown following both weight training and endurance cycling training.

From proteins to performance

But does all this microscopic protein building in the muscle actually translate into meaningful benefits to cyclists? The majority of the science to date has focussed on consuming protein after weight training; it shows enhanced recovery from a single training session, as well as significant improvements to muscle size and strength gains over several weeks.

There’s much less research in cycling and other endurance sports, and what exists is only scratching the surface of measuring performance that actually matters to athletes. So far it looks like there may be benefits from post-training protein for cyclists, in terms of increasing muscle power generation and the number of mitochondria in the muscle. Studies that looked at recovery from a single strenuous cycling session have only been measured in terms of performance during sprint intervals in the following days. Results so far are mixed – a couple of studies suggest a benefit to recovery, whilst others don’t show any benefit from consuming post-training protein.

I can’t find a single study to date that’s measured the effect of protein on recovery of long distance time trial performance.  And the effect of post-training protein on cycling performance after several weeks of training has never been studied either.

Although the benefits of post-training protein for cyclists isn’t yet clear, there’s nothing to suggest it’s detrimental to performance.  So I would suggest that taking protein after training is probably worth doing after long or intense training sessions, unless you have a specific reason not to. The benefits after a short or social ride is likely to be minimal so don’t worry about it in these situations.

What type of foods will give me this protein?

As I mentioned the key here is the amino acid Leucine, which is thought to “trigger” the muscles to increase their response to training. It takes about 3-4 grams of Leucine to achieve this – any extra is simply used as an energy source. The muscles also require other essential amino acids to “build” new proteins, so just taking 4 grams of a pure Leucine supplement won’t do the job.

The food source with the highest amount of naturally occurring Leucine (and other essential amino acids) is milk protein, and in particular the whey component of milk. That’s why you see so many whey protein powders on the market. If you’re a soy fan, the bad news is that soy protein has been shown to have less effect on muscles compared to dairy. But if it’s lactose you’re avoiding then lactose-free cow’s milk is available in most supermarkets and still contains the whey. Other good sources of Leucine are eggs, meat, fish and chicken.

Plant sources of protein are unfortunately not a great source of Leucine, and larger quantities of food are required to get the same effect. Nuts in particular are not a great option – getting the desired amount of Leucine would require 1 ½ cups of raw almonds, which also comes packed with 915 calories and 84 grams of fat!

How much protein do I need?

This all depends on what you’re eating. The most concentrated source of Leucine is Whey Protein Isolate powder, with only 25-30 grams needed. If you’re drinking milk (plain or flavoured) you’ll need about 800mL, or you could go for 4-6 eggs, 175g of meat, fish or chicken or 2 cups of lentils or kidney beans.

When do I need to consume protein?

The ideal timing to take the protein is still not completely understood (there’s a PhD study going on in conjunction with the AIS as we speak), but it appears that the first hour after training is important. If that coincides with a meal it makes life easy. But if you finish training between meals, or you’re out in the middle of nowhere and can’t get to a plate of food for a couple of hours, than you’ll need to be organised with an alternative. This is where protein powders may become a convenient way of getting your post-training protein – it’s portable and non-perishable. It’s not always practical or convenient to have eggs, meat or milk on hand when you finish training.

Translating that into breakfast, lunch & dinner

Putting this all together into something meaningful, I would suggest taking 20-30g of animal based protein (or 40-50g of plant based protein) for recovery within the first hour after long or intense training sessions. Here’s a list of options of what you might decide to take, that all provide enough Leucine and other amino acids:

After an early morning ride

2 eggs on toast plus a large skinny latte

Cereal with 250mL milk plus 250g yoghurt

Lunchtime

1 sandwich with 2 slices of ham or chicken (plus salad) plus 600mL flavoured milk

2 curried egg sandwiches (1 egg in each) plus a large latte

1 small can tuna or 100g chicken with salad plus 300g yoghurt

Dinner

200g meat, fish or chicken with any combination of starch (rice, pasta, etc.) and vegetables/salad

150g tofu with 1 egg and rice/noodles and vegetables, plus 250g yoghurt

1 cup red kidney beans or lentils plus 500mL milk (plain or flavoured)

Convenient options/snacks

30g whey protein isolate with water

20g whey protein isolate with 200mL milk

65g PowerBar Protein Plus or Sustagen Sport (both available in supermarkets) with 300ml milk

DIY Protein drink – 60g skim milk powder, 300mL milk plus flavouring of your choice

80g beef jerky

1 sandwich with 2 slices of ham or chicken (plus salad) plus 600mL flavoured milk

How much total protein do I need over the day?

Guidelines for protein intake of endurance athletes suggest that cyclists need around 1-1.5 grams of protein for every kilogram of body weight for optimal health and performance. Many Australians eat well and truly more than this already, but if you’re not big on meat, fish, chicken, dairy or soy products then you can end up eating significantly less. If you’re in a period of weight loss, some recent research suggests that increasing the amount of protein in your diet (up to 2-2.5 grams per kg) may help prevent loss of muscle mass as your weight goes down.

There’s also a theory (not yet conclusive) that spreading your protein more evenly across the day (in 20-30g portions) will increase the number of times the muscles experience the “trigger” effect from Leucine, and therefore produce more proteins in response. Bodybuilders have been doing this anecdotally for years and dietitians working with rugby clubs are starting to recommend it based on some early research evidence, but whether this approach will also enhance training adaptations in cyclists remains to be seen

Summary

Protein is an often misunderstood nutrient for athletes. It’s still not completely clear how important post-cycling protein is for recovery and for maximising the benefits from training, but we do know that it certainly won’t reduce your performance. Ideally have a decent source of protein in the first hour after a hard training ride or race. It doesn’t have to come in a giant plastic tub to give you the amino acids you need, but there are some situations where that’s simply the most convenient way to get your post-ride protein. The exact frequency and timing of your protein is still not understood, but little and often may prove to be better than one or two large doses over the day.