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Carbohydrates & Weight Training

Carbs For Muscle Fuel

Glucose, the simplest form of carbohydrates (carbs) is an important fuel for human muscle stored primarily as glycogen in the muscles but also available in the blood. Muscle glycogen is used up quickly during short, high intensity exercises and moderate repetitions. Lactate is also formed from anaerobic respiration to fuel muscle contractions, which gets recycled in the liver to glucose and transferred back to muscles. During rest and more prolonged exercise, fatty acids become the more preferred fuel.

Carbohydrates are basically of two types:

  • Simple Carbohydrates - These kinds of carbohydrate have simple molecular structure and release instant energy e.g. table sugar, dairy sugar. Too much of these kind of carbohydrates causes blood sugar peaks and valleys. Due to their "simple" molecular structure, they’re digested very quickly and they cause a rapid rise in blood sugar. Your body responds to blood sugar peaks by releasing large amounts of insulin. The over-secretion of Insulin activates fat storage enzymes and promotes the movement of triglycerides (fat) in the bloodstream into fat cells for storage. Insulin is an anabolic hormone that’s absolutely essential for getting amino acids into the muscles for growth and getting carbohydrates into the muscles where they're needed for energy. The problem is when there’s too much insulin and when resistance to insulin is produced by eating too many simple and refined carbohydrates. When your blood sugar and insulin levels are abnormally high, you're not in a fat-burning mode - you're in a fatstoring mode. The natural simple carbohydrates are "healthy," but ALL simple carbohydrates should be used in moderation during fat-reducing programs. Avoid all processed foods. Processed foods are ’empty’ calories that do nothing for your health or your fitness.
  • Complex Carbohydrates - The second major carbohydrate category is complex carbohydrates, also known as polysaccharides. Complex carbohydrates are formed when thousands of sugar molecules are linked together in long chains. They are again divided into two important categories:
  • Starchy Complex Carbohydrates - Starch is the storage form of energy in plants, much like glycogen is an energy storage form in human muscle. Starchy carbohydrates are found in potatoes, cereals, grains, bread, pasta, rice, oats, wheat and beans.
  • Fibrous Complex Carbohydrates (Fibre) - Fibre is the indigestible portion of the plant and therefore passes straight through your digestive tract without all the caloric energy being absorbed. Fiber gives bulk to the intestinal contents, promotes healthy digestion and elimination, speeds the transit time of food through the digestive tract and provides protection from gastrointestinal diseases and colon cancer. Fibrous carbohydrates (green vegetables) help you lose fat because they have a low calorie density.

Carbohydrate Tips For Bodybuilders

  • As glycogen is crucial to weight training, it is important to maintain optimum levels of muscle glycogen stores to maximise workout performance. Each individual varies in their training regime and total energy requirements thus requiring varying amounts of carbs. The suggested guidelines however are 5-6g carbs/kg/day, approximately 55-60% of total daily energy intake.1 However, if you were consuming a large amount of calories in a day, you should be using the 5-6g carbs/kg/day as a guide rather than a percentage of total daily energy intake.2

  • Contrary to popular belief especially restrain diets, carbs are not entirely bad and consuming the right amounts and type of carbs post-workout can maximize the rate of glycogen replenishment, thus improving performance in the subsequent session. It is proposed that the ideal levels are 1.2g carbs/kg/hour every 30 minutes, for 4 hours post-workout of high to moderate glycaemic index (GI) carbs. GI is a measure of the rate glucose enters the bloodstream after consumption. For even better replenishment of glycogen stores, it may be beneficial to combine the carbs with other nutrients3 – to be discussed in a future article.

Post-Workout Carbs For Muscle

It should be noted that the foods listed by GI are based per 50g carbs of food. Since different foods have different serve sizes, the glycaemic load (GL) has been established to gauge the impact of the amount of food on blood sugar. For example, a serving of pasta would provide 50 g carbs but not a serving of apple, thus pasta would have a higher glycaemic load. Proteins and fats, usually eaten with meals tend to lower the GL of a food. Essentially, it is crucial that nutrient rich foods be preferred in achieving our carb requirements.

High GI

Moderate GI

Sports drinks, juices, fruit (ripe banana, watermelon), potatoes, pumpkin, white rice, wholemeal bread, cornflakes, popcorn

Pasta, brown rice, wholegrain bread, wholegrain cereals, muesli bars, sultanas, honey, digestive biscuits

High GL

Moderate GL

White Rice, brown rice, raisins, baked potato, cous cous, sports drinks, white pasta

White bread, brown bread, spaghetti, bananas, oatmeal, rice cakes, fruit juice


1.Lambert, CP, LL Frank and WJ Evans, 'Macronutrient considerations for the sport of bodybuilding' (2004) 34(5) Sports Medicine 31
2. International Olympic Committee Consensus Statement. Journal of Sports Sciences 2004; 22: 1-146
3. Burke, LM, B Kiens and JL Ivy, 'Carbohydrates and fat for training and recovery' (2004) 22(1) Journal of Sports Sciences 15
4. Cardwell, G, Gold medal nutrition (Human Kinetics Publishers, 2006)
5. Insel, P et al, Nutrition (Jones & Bartlett Pub, 2010)


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