Carbohydrates need to be present in order to burn fat? However, Jack I thought carbs made me fat! Simply, carbohydrates need to be present in order for fat to be utilized as energy. If a low level of carbohydrates exists, a substance known as pyruvate begins to build up. Pyruvate is formed during glucose metabolism and if glucose is not present, pyruvate cannot do its job in the energy process.1 Therefore, fat has nowhere to attach in the body’s mitochondria, which in turn slows the metabolism, and will halt or extremely lessen the body’s fat-burning capabilities1. Furthermore, when the body lacks carbohydrates, critical amino acids are stripped out of muscle tissues as the body turns against itself (effecting amino acids such as branched-chain amino acids and alanine, as carbohydrates spare proteins). The moment the amount muscle tissue is decreased, the body’s metabolic rate is lowered substantially.
In 1994 at Tuffs University, Campbell et al2 used progressive resistance training three times per week over a 12 to 16 week period in order to study its effects on metabolism. Each session lasted only 30 minutes and on average the participants’ overall metabolic rate increased 34 to 35 additional calories with each newly formed pound of muscle.
This proves that an inverse relationship exists and that muscle burns more calories than fat, meaning that if muscle tissue is lost, metabolism will slow down.
Although several other studies conclude that muscle tissue only increases your metabolism by 4 to 10 extra calories per pound of muscle, it still points to muscle being more metabolically active. Wolfe et al3 determined that “the decreased availability of hepatic glycogen with fasting to decrease in the availability of plasma glucose, causes decrease in glucose oxidation, thereby inhibiting fat oxidation.” Furthermore, carbohydrates are the only one of three macro nutrients that produces ATP in the anaerobic cycle. Without this proper energy function, no muscle will be built. Therefore, while there is no such thing as an essential carbohydrate, carbohydrates are critical to an overall healthy metabolism.1
- McArdle WD, Katch FI, Katch VL. Exercise Physiology Nutritional. Energy, and Human Performance seventh, edition. 2010
- Campbell WW, Crim MC, Young VR, Evans WJ. Increased energy requirements and changes in body composition with resistance training in older adults. Am J Clin Nutr 75
- Wolfe RR. Metabolic interactions between glucose and fatty acids in human. Am J Clin Nutr