Nutrition 101

Nutrition is an important piece of the performance jigsaw. If you don’t eat well, your performance will certainly suffer – both in training and in racing. You may have different nutritional goals at different time. You goals may include: to lose or gain weight, recover quickly from training, or to optimize you race performance.

Background.

There are 3 basic macronutrients – carbohydrate, fat, and protein. All of these can be used as fuels by the body. You have limited stores of carbohydrate (approximately 2500-3500 calories), and this is your high-octane fuel. This is the primary fuel source for high intensity exercise, and carbohydrate stores are a limiting factor for endurance events.

Even very lean people have huge energy reserves in fat. However fat is a “slow burning” fuel, it takes a while to kick-in, and is only used in conjunction with carbohydrates. Optimizing fat burning, as an energy source, is essential for endurance events, to spare the valuable carbohydrate stores.

The body does use protein as an energy source, but it is not very efficient, and it is not considered good to use your muscle mass to fuel your body!

Your energy requirements are based on your base metabolism, and any activity on top of that. Your base metabolism is the energy you require to stay alive (breathing, eating, thinking etc). Any physical activities you do on top of basic daily functions burns further energy. Energy expenditure depends on your size, efficiency and how fast you go. This is true for both your base metabolism and physical activities.

Weight gain/lose.

In weight bearing exercise, such as running and cycling (particularly hills), your weight affects your performance. If you are carrying extra non-functional weight – such as fat, your performance will be reduced. In these circumstances, an easy way to improve your performance is to lose weight! However, becoming very lean does have its disadvantages. It is harder to gain strength, and power output maybe somewhat reduced. There are also immune system and recovery factors to be considered if you get too lean. Determining your “ideal” race weight will have to take these factors into account. To minimize strength losses, and general health considerations, weight loss should be gradual. Rapid weight loss plans will usually put the body into starvation mode – reducing your metabolism, losing muscle mass, and making weight loss (from fat stores) more difficult.

When you want to lose weight, it is usually fat that you want to lose, and conversely if weight gain is an aim, it is usually in the form of muscle. For weight lose, in a very basic sense, your output needs to be greater than input. If you consume less than you require – you will lose weight. To achieve this you can either decrease your input (eat less), and/or increase your output (exercise more). Of course it is not that easy – but that is the basic strategy.

Practical strategies for weight loss:

  • Keep your metabolism up. If you tend to starve yourself, your body goes into starvation mode, and reduces your base metabolism. To keep your metabolism high (and burn more calories), it is better to eat many small meals, rather than a few large meals. This also helps avoid the binge eating and keeps hunger at bay. A higher protein diet will also help, as it is difficult and inefficient for the body to convert protein to energy (and then to fat).
  • Eat more in the mornings and less at night. Eating less in the evening, particularly carbohydrates, gives the body less chance to convert all of that evening meal to “reserves”. Have more in the morning’s gives you the energy to get through the day as well.

Recovery

Your glycogen stores are what limit you to keep performing. After a hard training session your glycogen stores are very depleted. Eating high carbohydrate foods soon after the training session can optimize replenishing your glycogen stores. If you eat within the first 30 minutes after training your replenishment will be fastest, if your delay eating over one hour – your recovery maybe significantly delayed (by 1 to 3 days!). If you have a sweet tooth, post exercise is the best time to have those higher sugar foods. The sugar is quickly absorbed into the blood stream, and then to the muscles.

Protein replenishment also needs to be considered after hard training and racing. The body does not store protein for further use later. If protein is not available to repair muscle when needed – it cannot be repaired! After a hard training session (or race), it is also important to have reasonable protein intake to help the body repair any muscle damage that may have occurred.

An idea solution is a post training/racing milk shake – which included protein and carbohydrates. There are a number of replacement drinks and powders that you can use, and add in bananas, yogurt, low fat milk, and any other favorite or secret ingredient you wish.

Eating while training

You have a couple of competing objectives when training (apart from getting fitter!). You want to make the body more efficient at burning fat, and you also want to get use to eating plenty while under exercise pressure. To make the body more efficient at burning fat, you need to deplete your carbohydrate reserves somewhat, to put the body in glycogen sparing mode. Obviously you do not want the reserves to get too low or you will “hit the wall” or “bonk” (this is when you run out of carbohydrate stores). When you are starting out you will need to eat more, and as your body gets more efficient at burning fat as a fuel you can get by on less (at lower intensities, as you burn more fat). As a very rough guide, you should be consuming 100-200 calories per hour (more if you are larger and quite fit).

You also need to train to tolerate eating on the go. One problem when racing is that it is difficult to tolerate eating much food. You need to train the body to tolerate eating and digesting food (and water) while under exercise stress. For some key training sessions, it is a good idea to try and eat at least (if not more) than you plan to in the race. This is to ensure you can cope with eat the required amount. It will usually be more difficult in race conditions, than in training.

Energy of some common training/racing foods:

  • Squeezy – 100 kcal (25gm CHO)
  • Large banana – 90 kcal (22gm CHO)
  • Powerbar – 240 kcal (45gm CHO)
  • Power gel – 110 kcal (28 gm CHO)

Drinking

You need to replace your body’s fluid and electrolytes that are lost from sweat. If you lose 10% of your body weight (in sweat) – you are in extreme health danger in warm conditions (heat stroke and death!). A 5% loss will result in approximately a 50% decline in performance. If you weigh 70kg that is 3.5kg weight loss (or 3.5 liters of water). Maintaining fluid levels is therefore important for both health and performance reasons!

It is a good idea to work out your sweat rate. Weigh yourself before a training session (no clothes) and then after (no clothes). The weight loss is pretty much going to be your fluid loss. If you go for a 1 hour run, and lose 1.5kg, you need to drink 1.5 liters per hour to maintain hydration. The stomach can only process so much fluid (1-1.5 liters per hour) – and learning to tolerate drinking while exercising is also important.

For longer events, and if you do sweat a lot, you also need to consider your electrolytes. Taking large volumes of water only can lead to a large loss of sodium for the body (through sweat), and without replacing the sodium, can lead to hyponatremia. For events over 4 hours, and those in warm to hot conditions you will need to take on electrolytes – usually through an electrolyte drink or possibly with salt tablets. You may also need to add salt to your regular food.

Eating when racing.

This is an article in itself. However, as a basic rule the more carbohydrates you can tolerate, the faster you can go. Tolerating your food and fluid intake is very important, and very individual. You also need to practice and train on what you are going to race with. The golden rule is “nothing new on race day”. This also means that for longer events you will need to train on (at least some of the time) what is going to be available in the aid stations in the event as well as what you are going to use.