Beginner’s guide to carbs vs protein in sports nutrition

With the rise of protein-packed diets over the past decade, it’s no surprise that protein-laden sports nutrition is now similarly in vogue. But can protein ever parallel the importance carbohydrates play in assisting you reach your desired fitness levels?

Dietary requirements vary for different age groups, genders and activity levels, and sports nutrition is no different. But in order to remain healthy we all need carbs (carbohydrates), protein, fat, vitamins, minerals and water. What separates the diet of the recreational “keep-fitter” from the professional or competitive athlete is in the quantities and proportions in which those six are consumed.

Carbs, protein and fat provide energy, unlike vitamins, minerals or water. Carbs, followed by fats, are the main fuel for exercising muscles. But whereas even the most stick-thin of athletes have sufficient stores of fat, reserves of carbs are limited, so need replenishing before, and sometimes during, exercise. Protein’s strength, on the other hand, is in the growth, maintenance and repair of body tissue.

“Nutrition is everyone’s business and everyone has an opinion on it, but it is a science. I think it’s a testament that fad diets come and go, whereas if they were any good they’d actually stay,” says head of nutrition at the Irish Rugby Football Union (IRFU), Ruth Wood-Martin.

“A lot of these eating patterns being promoted at the moment are exclusively on protein, and that’s not necessarily the way to go. Nowadays, some nutrients get glorified while others are demonised. At the moment, protein is glorified and carbohydrates demonised, whereas there needs to be a balance of both.”

A clinical dietitian with more than 25 years’ experience, Wood-Martin has specialised in sports nutrition since 2007.

“The key job of carbohydrates is as an energy provider. It is muscles’ preferred source of fuel for exercise, especially at high intensity.

“On the other hand, protein’s job is not as a fuel provider but it is critically important to allow muscles to repair and recover post-exercise and for muscles to grow, particularly for young people.”

Carb-loading the day before an event is recognised as being a particular help to an endurance athlete exercising for three or more hours, but less relevant for the duration of your standard team sport (90 minutes or less).

Carb sources range from less-nutritious, sugar-based sweet foods – such as cakes, biscuits, muffins, fruit squash, jam, honey or jellies – which offer limited value as energy fuel, to higher-fibre forms that are more slowly absorbed. Such nutritious, high-carbohydrate forms include wholegrain breads and scones, oats, breakfast cereals, pasta, rice, potatoes (including sweet potatoes) and other root vegetables, beans, peas, lentils, fruit and low-fat yoghurt.

Carbs are stored in the body as glycogen and during exercise this is broken down into glucose, which feeds the working muscles with energy.

‘Enhances recovery’

“An optimal dietary carbohydrate intake enhances recovery and optimises glycogen stores for the next training session,” says Gillian McConnell, clinical dietitian and sports nutritionist at Inside Out Nutrition in Stillorgan and Greystones.

“One of the problems that I see is when people become carb-phobic, so they restrict calories, because they are very weight-conscious. People are afraid to eat carbohydrates because they have a fear of gaining weight and slowing down. This can be the farthest from the truth, as carbohydrates can help fuel the body and improve the speed and performance of exercise,” says McConnell.

“A nutritionally complete, balanced diet should provide ample amounts of energy, carbohydrates and protein to ensure optimal nutrition to support exercise performance.

‘Endorsed by celebrities’

“There is no one food that is a ‘super food’ and no one type of food should be consumed in abundance. Watch out for diets endorsed by celebrities; the chances are it is the latest fad diet. We need to be asking, is there any research behind this diet? What implications will it have for my health? How will it affect my exercise performance and lifestyle?”

But what of post-exercise? How soon after exercising should we be refuelling? While within hours is preferable, McConnell says the window of opportunity for optimal recovery to replenish carbohydrate stores is within one hour after intense exercise. This will help prevent stiffness and soreness and allow good energy levels for the next training session. However, if you’re not planning on exercising again for another two or three days, the relevance of that window shrinks dramatically.

And while protein plays a greater role in post-exercise nutrition, carbs are still king.

According to Wood-Martin, “If you’ve run 10km, for example, the main fuel you’ll have used is carbohydrate, so that’s what you need to refuel with. However, there will be perhaps some damage done to muscles, so some protein should be in there – ideally about 2:1 carbs:protein. But if someone’s particular focus is to lose fat weight, then that person may take less carbohydrate.

“Then if you take a gym session, your energy expenditure is not going to be as high as a 10km run and your recovery nutrition should reflect that. So you may concentrate more on protein rather than carbohydrate.”

According to the Irish Nutrition and Dietetic Institute, athletes taking part in strength and endurance sports have higher protein requirements than the standard, twice-a-week "keep fitters", but even those athletes can attain that through a varied, balanced diet.

“The key is to focus on protein quality,” says McConnell. “Use wholefoods where possible and ensure that if you are using supplements for convenience, that they are safe.”

High-quality dietary protein sources include milk – casein and whey – eggs, fish and lean meat (chicken or turkey), as well as beans, peas, lentils, cheese and nuts. So, even a large glass of fresh milk (containing carbs, protein and electrolytes in abundance) post-exercise will help with recovery.

But be it carbs or protein, all the fuel in the world will be of only limited use if you do not sufficiently hydrate. As the delivery system of fuel to the muscles, drinking water during and after exercise is of crucial importance.

According to McConnell, studies have shown that as little as 2 per cent dehydration can cause poorer performance, ball skills and concentration.“You need to drink water regularly every day and then step up on days of exercise to the degree that you will sweat,” says Wood-Martin. “Some people are big sweaters, while others don’t sweat so much.” For more articles on fitness, see irishtimes.com/health