Protein, essential fats and micronutrients are primarily used as building materials. Carbohydrate is really only used as fuel. To get lean, we want to burn up our supplies of excess fat, but to get consistently good performance, we need to give our bodies the right kind of fuel at the right time.
During exercise, we use ATP (adenosine triphosphate) which our bodies can get more easily from muscle glycogen and blood glucose than from stored fat. Muscle glycogen comes from blood glucose, which comes from the carbs that we eat.
You want your muscles to have a good supply of glycogen before you start exercising. Glucose in the blood still needs to be processed before it can be used, while glycogen in the muscles is ready to go. No amount of topping up during your ride will work as well as having a full tank to start with.
As soon as you finish one exercise session, you want to start preparing for the next. So, when you finish a ride, you want to rest, rehydrate and refuel. Your muscle glycogen stores replenish most efficiently straight after exercise - the first 4-6 hours is the best, especially the first 2, then it continues at a slower rate for about 24 hours. Straight after your ride, Michael Colgan
After that, you need to keep your carbohydrate intake steady, to keep your glycogen levels increasing. So it's better to eat your carbs in a series of small meals than in large ones that are widely spaced.
Before your next ride, you need to make sure your levels are topped up. 100-150 grams of an easily digested carbohydrate drink about 3 hours beforehand is the optimum.
You're ready for your ride. The question is : what shall I snack on during my ride? If you're only riding for an hour or so, and you've refuelled sufficiently beforehand, you probably don't need anything extra during. Just make sure you've got plenty of water. But if you're off for a longer session, it can be of benefit to keep the carbs trickling in. Colgan recommends 70-90g of a drink containing 5-10% of a solution that contains glucose polymers or glucose, plus a little fructose. Drink this at a rate of about 1 litre per hour.
Experts differ how much carbohydrate do we need. Training intensity and duration, as well as differences in your biochemical makeup, determine your carbohydrate requirements. The following table taken from "Optimum Sports Nutrition" by Michael Colgan gives a rough guide to the grams of carbohydrate you might need :
Bodyweight | Amount of training (hours per day) | |||||
kg | 2 | 3 | 4 | 5 | 6 | 7 |
40 | 200 | 300 | 400 | 500 | 600 | 700 |
50 | 300 | 400 | 500 | 600 | 700 | 800 |
60 | 400 | 500 | 600 | 700 | 800 | 900 |
70 | 500 | 600 | 700 | 800 | 900 | 1000 |
80 | 600 | 700 | 800 | 900 | 1000 | 1100 |
90 | 700 | 800 | 900 | 1000 | 1100 | 1200 |
100 | 800 | 900 | 1000 | 1100 | 1200 | 1300 |
110 | 900 | 1000 | 1100 | 1200 | 1300 | 1400 |
120 | 1000 | 1100 | 1200 | 1300 | 1400 | 1500 |
This allows for a small amount of overfeeding - if you start putting on weight, reduce this. If you are doing very high intensity exercise, you might need to increase this allowance. Let's look at our 80kg cyclist from the protein page. Riding for 2 hours a day, he'd need approx 600gms of carbs, riding for 4 hours he'd need approx 700gms.
Barry Sears (the Zone) recommends a lower level of carbohydrate. Work out your protein requirement, then add a third on to get your carbohydrate requirement. Our 80kg man cyclist with 20% body fat needed 112gms of protein - his carbo allowance would be about 150gms. Our leaner cyclist who needed 120gms protein, would need 160gms. This is vastly different from Colgan's recommendation for two reasons - the Zone has a higher % of fat intake, and it is reputed to allow you to burn stored fat more efficiently, which reduces your calorific needs.
Peter D'adamo (Eat Right For Your Blood Type) recommends different ratios for each blood type. His rough guidelines are 72% for A, 60% for AB, 56% for B, and 38% for O types. The metabolic diets range from minimal carbs for extreme Hunter-Gatherers to high carb for extreme Agriculturists. Traditional nutritionists and naturopaths tend to favour high carb diets.
You've already decided whose protein advice you're going to take, so stick with that expert and see how it goes. The acid test is how you feel, how well you ride and how lean you get. Give it a bit of time, as your body takes time to adjust to a new routine. If you don't get an improvement in performance, have a rethink.
The best kinds of carbohydrates are those that release sugar into your system at a steady rate. Dr David Jenkins developed the Glycaemic Index to help diabetics control their sugar levels. The GI of a food measures how quickly and how much it increases your blood sugar level. If the level goes up too much or too quickly, you get that "sugar rush" high, but then your body pumps out insulin to balance out the sugar & your energy levels drop again. Proteins and low GI carbs will help keep your blood sugar levels steadily within the right range.
So how do you know what foods are low GI? Here is a table showing a sampling of common foods. This listing uses glucose as the "standard" food with a factor of 100. (On the links page, there is a site will give you a much more comprehensive listing. It uses white bread as a standard, however. To convert the factors to the same scale as the table below, x by 0.7)
| Low GI Foods (below 55)/td> | Medium GI Foods (55-70) | High GI Foods (over 70) |
| Cereals | ||
| All Bran - 30 | Vita Brits - 61 | Weet-bix - 75 |
| Porridge - 42 | Nutrigrain - 66 | Cornflakes - 77 |
| Sultana Bran - 52 | Sustain - 68 | Rice bubbles - 89 |
| Grains/Pastas | ||
| Egg fettuccine - 32 | Basmati rice - 58 | Brown rice - 76 |
| Bulgur wheat - 48 | Pizza - 60 (av) | Sunbrown quick rice - 80 |
| Buckwheat - 54 | Taco shells - 68 | Calrose rice - 83 |
| Breads/Crackers | ||
| Mixed grain bread - 45 (av) | Pita bread - 57 | Wholemeal bread - 77 |
| Oat bran bread - 47 (av) | Ryvita - 69 | Rice cakes - 77 |
| Pumpernickel (rye) bread - 50 | White bread - 70 | Water crackers - 78 |
| Legumes | ||
| Kidney beans - 27 (av) | ||
| Lentils - 29 (av) | ||
| Chick peas - 33 (av) | ||
| Baked beans - 48 (av) | ||
| Vegetables | ||
| Green peas - 48 | Sweet corn - 55 | Pumpkin - 75 |
| Carrots - 49 | New potato - 62 (av) | Baked potato - 85 (av) |
| Yam - 51 | Beetroot - 64 | Parsnip - 97 |
| Sweet potato - 54 | ||
| Fruit | ||
| Cherries - 22 | Sultanas - 56 | Fruit leather - 70 |
| Grapefruit - 25 | Rock melon - 65 | Watermelon - 72 |
| Peach - 28 (av) | Pineapple - 66 | |
| Apple or pear - 36 (av) | ||
| Grapes - 43 | ||
| Kiwifruit - 52 | ||
| Banana - 53 (av) - note that ripe bananas have a much higher GI than starchy ones | ||
You also want carbs that are high in micronutrients. So make sure a high proportion of your carbs come from fruit, vegetables, unrefined grains and legumes. The more vitamins and minerals you get in your food, the less likely you are to need a supplement. If you are committed to health, you might like to try eating only whole foods and no refined carbohydrates.
If you are following a metabolic or blood type diet, consult the detailed lists for the specific carbs that will suit you best.
More: Macronutrients. Protein , Macronutrients. Fat (We Like It, Don't We?)
