Friday 1 February 2008

Nutrition Pt 3

There is much science on how much of what type of food athletes should eat, and it can get very confusing. However there are apparently some basic rules:
  • during periods of heavy training consume 8-10 grams of carbs per kg of body weight per day, if training mot so hard then 5-6 grams should be enough. Whilst tapering before an event, maintain the higher amounts.
  • consume about 1.5 grams of protein per kg of body weight per day
  • meet the remainder of your calorie requirements with fats and/or carbs.

During long rides expect to burn at least 2,000 calories. Riders on the Tour de France have been shown to burn over 5,000 calories a day.

Eating and drinking whilst riding can be critical to riding long hours day after day. On the big ride in the summer we should all be well fed at meal times, but we need to remain hydrated and with energy tanks topped up on the bike too.

What follows has been culled from various sources:

For the most part energy production during a long-distance ride happens at a relatively low rate, and it comes mostly from carbohydrate and fat with just a small contribution from protein. As you now know, carbohydrate is the preferred fuel for working muscles and is stored in the muscles and liver as glycogen. If you have not packed your muscles with glycogen (by consuming carbohydrate) before a ride, and replaced it during the ride and at the end of each day of a multi-day ride, the lack of carbohydrate can be a limiting factor on a long-distance ride.

Fat is also used, to a lesser extent than carbohydrate, but does not need to be replenished, as, unfortunately, your body's capacity to store fat is not limited in the same way as storage of carbohydrate is. The involvement of protein in energy production is never more than 10% of total energy expenditure, but it does result in a significant amount of protein being used from your body's protein stores. Protein is used as an energy source during the latter stages of a ride - when your body's carbohydrate stores have been depleted. During long exercise duration, if exercise continues beyond a certain point, it is more likely for protein to be used as an energy source. When protein is used as an energy source, it can exacerbate dehydration, as urine production is stimulated to speed the excretion of the waste products from protein (amino acid) breakdown. I have used recovery drinks after a long ride, such as REGO from SIS. I make up a big bottle before I go out and leave it in the fridge for when I get home.

It is advisable to eat some form of protein (meat, fish, and vegetarian alternative) twice a day, with lunch and dinner to meet your protein requirements. You do not need huge amounts of protein, even if you are trying to put on muscle mass. During exercise your body will actually attempt to keep its muscle glycogen stores intact and use some fat instead of burning carbohydrate whenever possible. However, during a long-distance ride at a steady pace, you will not be able to continue at the same pace if your carbohydrate stores run low. Fortunately, with training you can delay the point at which this occurs. Most cycling is aerobic and it uses both glycogen and fat but, perhaps when climbing a steep hill, anaerobic energy provision may momentarily replace it when the aerobic energy production is not quick enough in providing the necessary fuel. Anaerobic activity uses just glycogen.

Importance of hydration. During a four hour ride it is easy for you to lose 4-8 litres of sweat, which if not replaced will have a huge detrimental effect on your cycling performance. You may also suffer from cramp, which can be excruciating - believe me! Isotonic sports drinks (i.e. those 'in balance' with your body fluids) will provide fluid faster than any other type of drink. If you do not like these then you could alternate between sips of water and sips of a higher energy drink but you will also need a source of salt from a snack to facilitate fluid absorption. Don't wait until you feel thirsty before having a drink, you will already be dehydrated by then. The Race For Chase riders are all supported by LambdaSports and we will provide ZYM to those who want it. Zym is a lemon/lime flavoured hydration product in tablet form. Just pop one in a bottle and watch it fizz. It has vitamins and minerals lost in sweating and has certainly made a difference to my riding comfort.

Balanced diet. Fat intake needs to be kept low for two reasons: (a) it is not necessary to replace fat stores between bouts of activity; and (b) less fat in the diet means that you are more likely to eat more carbohydrate foods and avoid unwanted weight gain.

Unless you are following a vegetarian or low-energy diet, it is more likely that you are eating too much, rather than too little, protein. It is important that you do not consume an excess of protein over a long period since the excess protein calories are stored as fat it can easily lead to unwanted weight gain.
Do eat plenty of carbohydrate rich foods
Avoid too much fat
Eat 'normal' amounts of protein, i.e. not large quantities of meat, eggs and milk.

Suggested food & drink for training/riding. During our long training rides and the main event you have a greater choice of foods, as you will be consuming a greater proportion of your energy consumption for the day on the bike. Suitable foods include banana, jam or other low-fat sandwiches, cereal bars, flapjack, malt loaf, scones, bagels, low-fat cake bars, low-fat biscuits, currant buns and teacakes. Energy bars and gels from the big producers, such as TORQ, SIS, GO-BAR, POWEBAR etc are all OK, and you will have to experiment to find what suits you. There are some energy gels with caffeine to give you a boost. Bear in mind that with a gel you must drink water too, and after a day of energy drink and bars your teeth will need a serious brushing!! I used to make my own flapjacks, with fruit, seeds and nuts, and these had less chemicals than the commercial ones!

Timing of eating. Aim to take on an average of 30-60g of carbohydrate per hour, to maintain your performance level. This is equivalent to 1-2 cereal bars, or 1-2 large bananas, or 500-1000ml of an isotonic sports drink.

'Carb loading' is an eating regime, which aims to pack muscle glycogen stores to the brim before exercise. This involves tapering training over the days leading up to an event, to cut down on muscle glycogen utilisation. At the same time the amount of carbohydrate in the diet is increased to supply the muscles with glycogen. However, athletes do report mixed reports on its effectiveness.

Foods to avoid. Be careful with the amount of high-energy drinks you consume. These drinks do not cause problems in small quantities, or when interspersed with water but too much can dehydrate you and upset your stomach. When I did LeJoG in 2005 the one rider who dropped out was struggling on day 1 and when he felt tired would just drink another energy product - I think he got sick from it.

You may also consider drinks which are lower in carbohydrate, like fruit squash or an isotonic drink. These will not only provide fluid quickly, but will also supply some carbohydrate. However, you may find that your palate or your stomach doesn't like a particular drink. It's worth trying out different brands on shorter rides before you embark on a long ride to decide which ones you can tolerate. I used to use High5 neutral flavour and add my own squash. There are many energy drinks with electrolytes and/or protein on the market. FuelCycling does sample packs which may be worth trying out.

Foods such as pasties, sausage rolls, pork pies and Scotch eggs are not good choices for snacks, as they are high in fat and do not provide any carbohydrate.

Ultimately you will all need to find what suits you personally, as we are all different. One chap I know hardly ever carried anything on training rides, and when one day he had a small bottle of water we all thought that this was going to be a really tough day. It is nice to go for a training ride and stop for lunch or tea, and have a pot of tea and a cake!

For the moment I am sticking to High5 Energy Source, Zym and probably malt loaf for solids. I made the mistake recently of not eating but relying on liquid, and that is not enough for me. If I feel my stomach is empty I get grumpy at the best of times!

Happy riding!

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