This is the third and final installment in the Animalbolics series. However, this article goes way beyond just what to eat and when. This is my own attempt to explain the very basics of how the components of this diet work. This is more or less a lesson into how hormones affect the way our body uses food.

There are 6 hormones that are chiefly responsible for determining whether the food we eat ends up as muscle, fat or just get burned as energy are: insulin, glucagon, growth hormone, thyroid hormone, cortisol and epinephrine.

Over 90% of people who lose weight by caloric restriction return to their original weight within two years. This is because there is a weight-regulating center in your hypothalamus, which tries to maintain a constant body weight. (The hypothalamus and pituitary gland together represent the master endocrine gland of the body, controlling all of your hormonal responses.) It works like a thermostat by controlling your hunger level and your body's metabolic rate. These effects are mediated by the nervous system and by hormones and enzymes involved in fat metabolism. If you want to change your body weight, or your body composition, you have to change the set point. The ratio of insulin to glucagon is perhaps the most important determinant of the set point and Animalbolics is the method to control this.

Obese people are very rarely overweight because they overeat, but rather because the way they eat and their lack of exercise raise the set point and act to channel calories to fat stores.

So how do you get control of your hormones and use this information to be a better bodybuilder? By careful control of your diet and exercise habits. The most important hormones involved in muscle growth are growth hormone (whose effect is largely mediated by the paracrine hormone IGF1), insulin and testosterone.

The most important hormones in fat loss are insulin (lack of insulin, that is), epinephrine, growth hormone, glucagon, thyroid hormone and cortisol. Most of these can be controlled by diet and exercise and will fall within optimal levels if you follow our nutrition and training guidelines.

As you can see insulin is a very important hormone to maintain control of when looking to lose fat. Insulin is a protein hormone, produced in the islets of Langerhans of the pancreas that regulates the metabolism of carbohydrates, fats, and starches in the body. The most important role of insulin is to regulate blood glucose levels. It does this by moving glucose into cells after a meal. It also increases the use of glucose for energy and increases glycogen stores. Too much insulin has the effect of promoting fat storage.

Both insulin and glucagon are produced by the pancreas, but have opposite effects. The concern of these hormones is blood sugar regulation. After eating a carbohydrate, it is digested and sent into the bloodstream as glucose. As blood glucose levels rise, so does the release of insulin, which is required to move glucose into muscle cells for use as energy or to be stored as glycogen. If blood sugar levels rise too quickly, a large insulin release results. When this occurs, some of the glucose can be converted and stored as fat instead of being stored as glycogen. Also, too much glucose can be moved into cells, causing hypoglycemia. Glucagon is released when blood glucose levels become too low. This hormone prepares fat to be used for energy as well as muscle glycogen stores. The net result is to keep blood glucose levels normalized. By manipulation of the diet, you can regulate the insulin to glucagon ratio. This is a basic premise of Animalbolics. By negating carbohydrates you force your blood glucose levels so low that glucagon is released. Glucagon must be released in great quantities to work effectively at fat burning. So an extreme lack of insulin is necessary.

When you eat carbohydrates they are digested and absorbed by the small intestine and transported directly to the liver via the portal vein. Essentially, 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 released. This rise in blood sugar triggers a release of insulin from the pancreas. Insulin is required to help move glucose into cells by a process called "facilitate diffusion." Once inside cells, the glucose is burned for energy or stored as glycogen. This is a normal body function. The problem arises when carbohydrates are released into the bloodstream too fast. This causes too much insulin to be released. When insulin levels get too high, some of the carbohydrate is converted to fat instead of being stored as glycogen. Also, if insulin levels get too high this actually causes too much sugar to be moved into cells. This results in "hypoglycemia," which means low blood sugar. If your blood sugar is too low you feel very tired. Simple sugars cause your blood sugar level to spike, then paradoxically to decrease to a lower level than before.

Glucagon is a 29 amino acid peptide hormone liberated in the A-cells of the islets of Langerhans. Glucagon-producing A cells represent one of the earliest populations of detectable islet cells in the developing endocrine pancreas. The key biological actions of glucagon converge on regulation of glucose homeostasis through enhanced synthesis and mobilization of glucose in the liver. It has the opposite effect of insulin. An increase in blood sugar triggers a release of insulin but inhibits glucagon release. Glucagon is released several hours after a meal when blood sugar levels drop. Glucagon has the effect of reducing glucose for energy and stimulating breakdown of body fat and the use of fat for energy. Glucagon also stimulates the glycogen breakdown. The net result of glucagon is to raise the glucose levels back to normal and to signal the body to begin using fat for energy since it's running low on carbs. This is how the insulin-glucagon axis acts to regulate blood sugar levels. Insulin decreases blood sugar by moving glucose into the cells, stimulating glucose burning for energy and increasing glycogen storage. Glucagon acts to increase blood glucose levels by stimulating glycogen breakdown, stimulating glucose synthesis by a process known as gluconeogenesis, and by shifting the metabolism from carb-burning to fat-burning.

Glucagon decreases phosphofructokinase and glycogen synthase, which decrease glycolysis and glycogen synthesis, respectively. Glucagon also increases the activities of fructose-1, 6-biphosphatase and phosphorylase, which increase gluconeogenesis and glycogenolysis, respectively. Regarding fat metabolism, insulin acts to stimulate aceytl-CoA carboxylase and lipoprotein lipase, the most important enzymes regulating fat synthesis and storage, respectively. Glucagon inhibits these same two enzymes. In addition, glucagon activates adenylate cyclase, which initiates a cascade of events resulting in mobilization of fatty acids from fat stores. The fats are then transported to the muscles and used for energy.

While insulin and glucagon are controlled entirely by diet, the most effective way to control growth hormone, testosterone and epinephrine is by exercise. This is why exercise is required to gain muscle and lose fat. If you try to lose weight by cutting calories, about half of the weight you will lose will be muscle. Conversely, if you gain weight simply by increasing calories without exercising; you'll just get fat. Exercise is required to set up the proper hormonal milieu allowing selective fat loss and muscle gain. The favorable effects of exercise in increasing muscle mass while decreasing fat stores are mediated largely through growth hormone, testosterone and epinephrine.

Growth hormone (GH) is the most important hormone responsible for normal growth during childhood. Human growth hormone (also called somatotropin) is a protein of 191 amino acids. The GH-secreting cells are stimulated to synthesize and release GH by the intermittent arrival of growth hormone releasing hormone (GHRH) from the hypothalamus. GH promotes body growth by:

• binding to receptors on the surface of liver cells
• this stimulates them to release insulin-like growth factor-1 (IGF-1; also known as somatomedin)
• IGF-1 acts directly on the ends of the long bones promoting their growth

Without growth hormone, a person will never attain adult stature. Growth hormone has profound effects on the growth of the skeleton as well as the muscles. Testosterone and estrogen produced during puberty cause the skeleton to mature and stop growing, but growth hormone still promotes muscle growth and fat loss in adults. Growth hormone is released from the pituitary gland when it receives the appropriate signals. One of these signals is "growth hormone releasing hormone" (GHRH) which comes from the hypothalamus.

There are several things you can do to naturally increase your GH levels. One is to get a good night's sleep. Growth hormone is released maximally during sleep, normally about three hours after you fall asleep. Trying to build muscle without getting enough rest is nearly impossible. Second, GH release is increased during and just after intense exercise. The most effective training style for increasing GH release is high volume training. Third, eat a high protein diet. This not only stimulates GH release, but also provides the building blocks you need to build new muscle tissue. Fourth, certain combinations of amino acids have been shown to increase GH release and result in increased lean body mass.

Insulin: Optimal concentrations of insulin are required for normal growth during postnatal life. Insulin stimulates protein synthesis and inhibits protein breakdown. Without insulin, normal responses to GH are not seen and protein breakdown is severe. Insulin promotes growth primarily by shuttling nutrients (glucose and some amino acids) inside cells, providing energy and the building blocks for protein synthesis. Note that insulin and GH must both be present at the same time for normal growth to occur. This is because insulin and GH each shuttle a DIFFERENT compliment of essential amino acids inside cells, and of course all of the essential amino acids must be present at the same time for protein synthesis (and thus growth) to occur. Neither insulin nor GH alone is sufficient to support normal growth - it takes optimal levels of all the body's hormones to produce optimal health and optimal gains. As noted in a previous bulletin, excess insulin cannot create muscle mass, but it will promote fat storage. It's not the calories in sugar that make you fat - it's the insulin response.

Glucocorticoids: Glucocorticoids (primarily cortisol) promote optimal function of a wide variety of organ systems, but do not have direct growth promoting actions. Excess GC's inhibit growth by the catabolic effects of cortisol (increased protein breakdown). Normal levels of GC's seem to be needed to permit optimal function of the other hormones. The concept here is that glucocorticoids act to stimulate (or maintain) optimal levels (amounts) of metabolic enzymes, whose activities in turn are regulated by the other hormones. GC's sort of set the stage and make sure all of the machinery is in place. Cortisol functions to make sure the key regulatory enzymes are present in sufficient amounts to allow allosteric regulation (enzyme regulation via small effector molecules such as metabolic intermediates) and enzyme regulation by other hormones. Also, cortisol is important in maintenance of glucose levels and resistance to stress, which intuitively would seem important for normal growth.

Thyroid hormone is present in two forms, known as T3 and T4 {triiodothyronine (T₃) and thyroxine (T₄)} T₄ and T₃ are derivatives of the amino acid tyrosine with three (T₃) or four (T₄) atoms of iodine. These two hormones have many effects on the body. Among the most prominent of these are:

• an increase in metabolic rate (seen by a rise in the uptake of oxygen)
• an increase in the rate and strength of the heart beat

Most of the circulating hormone is in the form of T4 that is converted to the more active T3 form inside target cells. Thyroidectomy (removal of the thyroid gland) has nearly as devastating an effect on growth as does hypophysectomy (removal of the pituitary gland - the body's source of GH). Restoration of T3 and T4 promptly reinitiates growth. T3 and T4 have little if any growth promoting effect in the absence of GH however. T3 acts to promote the actions of GH at three levels: GH synthesis, GH secretion and GH action. Plasma concentrations of GH are very low in the absence of T3 or T4. This action is independent of GHRH (growth hormone releasing hormone) and appears to be exerted directly at the level of gene transcription. In addition to its permissive effects on GH synthesis, T3 maintains normal responsiveness of somatotropes (the cells that make GH) to GHRH. Failure of growth in thyroid deficient individuals is largely due to GH deficiency. However, even large amounts of GH cannot sustain normal growth in thyroidectomized animals unless thyroid hormone is also given. Thyroxin decreases the amount of GH needed to stimulate growth (increases sensitivity) and exaggerates the magnitude of the response (increases efficacy). T3 and T4 seem to potentate the effects of GH on long bones and to increase its effects on protein synthesis in muscle and liver.

Controlling all of the above hormones is key when looking to maximize muscle gains and /or fat loss. The premise behind Animalbolics allows you to do this more effectively than most diets. Learning about these hormones and how they work and relate to each other is a good step in helping to plan your own diet and training regimen. For more information about the above topics I would suggest the following reading:

To quote Chris Thibaudeau:

"I suck at writing article conclusions so there is none to this one, good night and God bless!"

References:

1. Remington DW, Fisher AG and Parent EA. How to Lower your Fat Thermostat. Vitality House International, Provo, 1983.

2. de Castro JM, Paullin SK and DeLugas GM. Insulin and glucagon as determinants of body weight set point and microregulation in rats. J. Comp. Physiol. Psychol. 92: 571-579, 1978.

3. Guyton AC. Textbook of Medical Physiology. WB Saunders, 1991.

4. Westphal, SA, Gannon MC and Nuttall FQ. Metabolic response to glucose ingested with various amounts of protein. Am. J. Clin. Nutr. 52: 267-272, 1990.

5. Mathews CK and van Holde KE. Biochemistry. Benjamin/Cummings Publishing Company, Redwood, 1990.

6. de Castro JM, Paullin SK, and DeLugas GM. Insulin and glucagon as determinants of body weight set point and microregulation in rats. J. Comp. Physiol. Psychol. 92: 571-579, 1978.

7. 2. Remington DW, Fisher AG, and Parent EA. How to Lower your Fat Thermostat. Vitality House International, Provo, 1983.

8. Guyton, AC. Textbook of Medical Physiology. W.B. Saunders, 1991.

9. Johnson LR. Essential Medical Physiology. Raven Press, New York, 1992.

10. Kraemer WJ. Influence of the endocrine system on resistance training adaptations. Natl. Strength and Conditioning J. 14: 47-54, 1992.

11. Kraemer RR. Kilgore JL, Kraemer GR, and Castracane VD. Growth hormone, IGF-1, and testosterone responses to resistive exercise. Med. Sci. Sports Exerc. 24: 1346-1352, 1992.

12. Crist DM. Growth Hormone Synergism. DMC Health Sciences, Albuquerque, 1991.

13. Dr. Daniel J. Drucker, Toronto General Hospital, University of Toronto.

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