The effects of carbohydrate intake before rugby games

Carbs are a controversial nutritional subject. On the one hand, carbs are often blamed for the current obesity crisis. Sugar, in particular, is considered to be very unhealthy. On the other hand, without carbs, you won’t have the glucose and glycogen you need to power you through your rugby games and workouts. It’s all very confusing.

The truth is that the more active you are, the more carbs you need and can tolerate. In contrast, if you are mostly sedentary and want to lose weight, cutting carbs is a very effective strategy.

In short, carbs are neither good or bad and blanket media statements like “carbs make you fat” are very unhelpful. As a rugger, your nutritional requirements are very different from a couch-surfer who never walks further than the fridge and back.

Carbs and rugby

Rugby, like most team sports, involves a lot of starts and stops. It’s an anaerobic sport which means most of your energy comes from the creatine-phosphate and the lactate energy systems as much or more so than the your oxidative system. The CP system uses chemical energy whereas the lactate system involves the breakdown of glucose and glycogen in an oxygen-free environment.

Glycogen is a limited resource; you can only store so much. The amount of glycogen in your body depends on several factors including how well trained you are, the size of your muscles, and your nutritional status. An average-sized male should have around 500 grams of glycogen in their muscles, and an additional 100 grams in their liver. This is equal to approximately 2,400 calories of usable energy.

2,400 calories is a lot of fuel. In theory that amount of energy should keep you going for at least a couple of hours – definitely longer than a rugby match even with overtime. However, there is a problem. Glycogen is stored locally. This means the glycogen in your quads can only be used by your quads, and the glycogen in your pecs can only be used by your pecs. Once depleted, performance will decline significantly. This goes for the gym, the rugby field or anywhere else. 

To avoid this problem, it’s crucial that you start your training session or rugby match with full glycogen stores. If you run out of glycogen, your performance (like a cheating soccer player) will take a dive. Your limbs will feel heavy, and you’ll lose power and strength.

Consuming carbs at half-time can help, but even carbs with a high glycemic index take time to be digested and assimilated – typically 15-30 minutes. By this point, your declining performance may be beyond saving.

Research confirms the fact that ruggers need carbs prior to activity to perform at their best. In one study, test participants were given either a high carb or low carb diet and tested using a 60-min intermittent-sprint exercise (ISE) protocol that included 15-meter maximal sprints every minute and self-paced efforts of varying intensities. The test participants were not told if they were in the high carb or low carb group; the carbs were administered in the form of a drink.

While both groups reported the same rating of perceived exertion, the high carb group performed 4-8% better than the low carb group. Post-test strength was also significantly higher for the high carb group.

Getting the most from pre-activity carbs

Now you are hopefully sold on the need for carbs before rugby, make sure you follow the following rules so that you get the best results from what you eat.

1. Increase your carb intake the day before your game

It takes time to convert carbohydrate into glycogen. Chowing down a lot of carbs the day of a game may be too late. Increase your carb intake the day before a game to make sure your glycogen stores are topped up. Avoid training on this day, other than some light cardio and stretching, to make sure you do not use these stores too soon.

2. Avoid high-fiber carbs when you are trying to increase glycogen stores

Fiber is an essential nutrient. It’s good for the health of your digestive system. Most ruggers should eat at least 25-30 grams of fiber per day. However, high fiber carbs like veggies and wild rice are not a good choice for glycogen replenishment. Fiber slows the digestive process which means you may delay glycogen conversion and storage. This is particularly true on game day.

Eat plenty of fibrous carbs throughout the week but, on the day before and the day of your game, make the switch to low fiber carbs like white bread, white rice, skinless potatoes, and white pasta as they are digested more quickly.

3. Eat fewer carbs on non-training days

Because carbs are such an important source of energy for ruggers, it makes sense you should be a carb-fiend seven days a week, but that could be a mistake. If you eat more carbs than you need, they are more likely to be converted to and stored as fat. Eating fewer carbs on non-training days will prevent this problem. Getting to Ketosis isn’t essential to see the benefits of a low-carb, healthy fat diet. 

Also, sporadically lowering your carb intake increases insulin sensitivity. This means that, when you increase your carb intake again, more of those carbs will be converted to and stored as glycogen. In short, a brief carb hiatus will help you store more glycogen than normal.

4. Consume fast-acting carbs an hour or so before your game, and during half-time

To get the most from carbs, you need to consume them the day before your game. However, consuming fast-acting carbs (specifically glucose) shortly before and midway through your game will ensure your glycogen stores are as full as possible.

Good choices include candy, energy bars, energy gels, sports drinks, cereal bars, and even non-alcoholic beer or flat soda. Learn more about halftime nutrition, it’s the lowest hanging fruit in amateur rugby. Remember though, this is like putting the icing on the cake. Consuming fast-acting carbs at this point will only have a small impact on your glycogen stores.

The more active you are, the more carbs you can and should eat. Leave the low-carb diets to sedentary, overweight people. Ruggers need carbs for energy and performance. If you want to play at your best, for the entire 80-minute game, make sure you eat adequate amounts of carbs.


Patrick Dale

Patrick Dale

Pat is an ex-Royal Marine and owner at fitness qualifications company Solar Fitness Qualifications Ltd. Pat has authored three exercise books and thousands of articles. Pat has competed at a high level in several sports including rugby, triathlon, rock climbing and powerlifting.