Metabolism (i.e. the process in which food is converted to provide energy and to produce and maintain cells and tissues) is a key concept for achieving a full comprehension of body physiology and being able to improve your bodybuilding program with this knowledge. This post exposes the basic issues for understating your metabolism.
Metabolism is mainly controlled by two hormones: insulin and glucagon. The most important role of these hormones is to regulate blood glucose levels, but also the fat storing/releasing process into/from the adipose tissue. Both insulin and glucagon are produced by the pancreas, but they have opposite biological functions. If one is secreted, the opposite hormone secretion is inhibited and vice versa.
All of the carbohydrates you eat are converted to glucose by the liver before being released into the bloodstream. After a meal your blood glucose level rises as carbohydrates are absorbed. In order to avoid reaching dangerous glucose levels, this rise in blood glucose triggers a release of insulin. Insulin decreases blood sugar by moving glucose into the muscle cells to be used as an energy source or to be stored as glycogen and also by storing glycogen in the liver. When the muscles cells and the liver are full or when a great amount of insulin has been released (because blood sugar levels have risen too quickly), insulin converts and stores as fat some of the glucose instead of storing it as glycogen. This occurs because insulin shuts down your fat burn capacity and activates your fat storage capacity.
Moreover, if insulin levels get too high, this causes too much glucose to be moved into cells, producing hypoglycemia (low blood sugar). This occurs, for example, when eating high GI carbohydrates. Initially your blood sugar level spikes, and then paradoxically insulin decreases it to a lower level than before. Normally, the body would compensate this by mobilizing some stored fat, but since insulin has switched off your fat burning capacity, this is not possible. Body solves this by breaking down muscle protein for energy, because it is the tissue that consumes more calories. In addition, maintaining high insulin levels over a long period of time (e.g. eating too many carbohydrates) reduces insulin sensitivity. This motivates releasing more insulin to reinforce the reduction of blood glucose level. This is very dangerous, since keeping in this state can lead to diabetes.
You can prevent muscle breakdown and increase your insulin sensitivity by limiting high GI carbohydrates from your diet (except just after your workout) and by training, because training depletes the stored glycogen in the muscle, so when glucose enters the bloodstream, you're not force-feeding the muscles, you're just feeding them something they want and need. This also justifies why it is good to eat high GI carbohydrates just after training.
Insulin is highly anabolic. It facilitates amino acid transport into muscle cells, and also blocks many catabolic processes and due to this it is one of the key factors determining your muscle growth. Hence it is advisable to create an insulin spike just after training in order to gain mass.
Glucagon is released when blood glucose levels become too low. This hormone aims to raise the glucose levels back to normal by preparing glycogen stores to be used for energy. In addition, glucagon has the effect of stimulating breakdown of body fat to be used for energy. Glucagon also shifts the metabolism from carbohydrate burning to fat burning.
You can complement the metabolism information in this post by reading the article “Blood Sugar & Insulin” by Matt Danielsson, the article “The Blood Sugar Hormones” by Derek Charlebois and the “Metabolism” section of Muscle 101 site.
Metabolism is mainly controlled by two hormones: insulin and glucagon. The most important role of these hormones is to regulate blood glucose levels, but also the fat storing/releasing process into/from the adipose tissue. Both insulin and glucagon are produced by the pancreas, but they have opposite biological functions. If one is secreted, the opposite hormone secretion is inhibited and vice versa.
All of the carbohydrates you eat are converted to glucose by the liver before being released into the bloodstream. After a meal your blood glucose level rises as carbohydrates are absorbed. In order to avoid reaching dangerous glucose levels, this rise in blood glucose triggers a release of insulin. Insulin decreases blood sugar by moving glucose into the muscle cells to be used as an energy source or to be stored as glycogen and also by storing glycogen in the liver. When the muscles cells and the liver are full or when a great amount of insulin has been released (because blood sugar levels have risen too quickly), insulin converts and stores as fat some of the glucose instead of storing it as glycogen. This occurs because insulin shuts down your fat burn capacity and activates your fat storage capacity.
Moreover, if insulin levels get too high, this causes too much glucose to be moved into cells, producing hypoglycemia (low blood sugar). This occurs, for example, when eating high GI carbohydrates. Initially your blood sugar level spikes, and then paradoxically insulin decreases it to a lower level than before. Normally, the body would compensate this by mobilizing some stored fat, but since insulin has switched off your fat burning capacity, this is not possible. Body solves this by breaking down muscle protein for energy, because it is the tissue that consumes more calories. In addition, maintaining high insulin levels over a long period of time (e.g. eating too many carbohydrates) reduces insulin sensitivity. This motivates releasing more insulin to reinforce the reduction of blood glucose level. This is very dangerous, since keeping in this state can lead to diabetes.
You can prevent muscle breakdown and increase your insulin sensitivity by limiting high GI carbohydrates from your diet (except just after your workout) and by training, because training depletes the stored glycogen in the muscle, so when glucose enters the bloodstream, you're not force-feeding the muscles, you're just feeding them something they want and need. This also justifies why it is good to eat high GI carbohydrates just after training.
Insulin is highly anabolic. It facilitates amino acid transport into muscle cells, and also blocks many catabolic processes and due to this it is one of the key factors determining your muscle growth. Hence it is advisable to create an insulin spike just after training in order to gain mass.
Glucagon is released when blood glucose levels become too low. This hormone aims to raise the glucose levels back to normal by preparing glycogen stores to be used for energy. In addition, glucagon has the effect of stimulating breakdown of body fat to be used for energy. Glucagon also shifts the metabolism from carbohydrate burning to fat burning.
You can complement the metabolism information in this post by reading the article “Blood Sugar & Insulin” by Matt Danielsson, the article “The Blood Sugar Hormones” by Derek Charlebois and the “Metabolism” section of Muscle 101 site.
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2 comments:
I have read almost every article up to just now. I've enjoyed very much. Very sensible and well documented stuff. Keep on writing!
Thanks for your kind words!
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