Growth Hormone and Blood Sugar
The most important point in regards to growth hormone (GH) and diet is that "Growth hormone levels increase significantly when insulin levels are low" (Jamieson, p. 85). "More precisely, the cause of growth hormone inhibition is not high insulin levels but rather high blood sugar (which, because insulin is secreted to bring down blood sugar level, overlaps in time with high insulin levels)" (Faigin, p.201).
To explain further, "… glucose inhibits the secretion of growth hormone by acting on specific areas of the hypothalamus. Consequently, during the day, when food is consumed periodically, growth hormone secretion by the pituitary is suppressed, and insulin release by the pancreas is increased" (Dean).
But it should be noted that it is not just any food that causes a rise in blood sugar and the consequent insulin release, but primary carbohydrates. And some kinds of carbs cause a greater blood sugar increase than others. This issue is discussed in the article *The Glycemic Index.
I won't repeat all the details of that article here, but the important point is that low glycemic foods will not increase blood sugar as much as high glycemic foods. And eating a large amount of carbs at once will cause a greater increase in blood sugar levels than eating a small amount of carbs. Also, eating fat with carbs will blunt the rise in blood sugar.
What this means is, consuming a large amount of high glycemic carbs by themselves could completely halt growth hormone release. Or more generally, a high carbohydrate, low fat diet is absolutely devastating to growth hormone levels. This is one of the reasons why many people trying to lose weight on such a diet "plateau" after a period of time. Their inability to continue to lose weight is partly due to suppressed GH levels.
Moreover, a study comparing a group of boys consuming meals composed of high-glycemic index (GI) foods verses low GI foods found, "There were higher levels of the hormones insulin, noradrenaline, and cortisol after the high-GI meals" (Brand-Miller, p.230). So a rapid rise in blood sugar and insulin can lead to a rise in cortisol, with its attendant catabolic and lipogenic properties.
However, "… we need insulin to promote the benefits of growth hormone. Studies show that GH fails to cause growth in animals lacking a pancreas and it also fails if carbohydrates are restricted from the diet" (Jamieson, p.56). The reason for his could be that a strict low carb diet would lead to chronically low insulin levels, and insulin, as indicated above, is needed to drive amino acids into the muscle cells.
Moreover, IGF-1 is produced in the body through the combined actions of GH and insulin. And IGF-1 "… is at least as powerful an anabolic agent as either of its parents" (Faigin, p. 90). But a low carb diet would lead to a reduction in IGF-1 levels. So a low carb diet is not the answer either. In fact, this relationship of insulin, growth hormone, and IGF-1 is one reason why those following a low carb diet also often plateau after a period of time.
There is a relationship with thyroid hormone here as well. "Raising GH has a profound effect on normalizing thyroid function … " (Jamieson, p.100). However, "Studies also show that diets that continuously restrict carbohydrate (like the Atkin's diet, for instance) cause a reduction in T3, and that administering carbohydrate can restore T3 levels after they have declined" (Faigin, p.139). This reduction in T3 is another reason people will often plateau on low carb diets.
So an ideal GH enhancing diet would include some carbs, but not an excessive amount. And the focus would be on low glycemic carbs.
RESOURCES: Sources:
Brand-Miller, Jennie, et. al. The New Glucose Revolution. Marlowe & Company: New York, 2003.
Creatine Newsletter. Issue 20. "Growth Hormone De-Mystified" -
**broken link removed**.
Dean, Ward M.D. "Neuroendocrine Theory of Aging Chapter 3; Part 1 Energy Homeostat Dysfunction" -
http://www.vrp.com/art/253.asp.
Di Pasquale, Mauro. The Anabolic Solution for Powerlifters. N/A. 2002. For details on this book and nutrition program, see the Metabolic Diet Web site:
The Metabolic Diet.
Faigin, Rob. Natural Hormonal Enhancement. Extique Publishing: Cedar Mountain, NC. 2000. For details on this book and nutrition program see the Extique Web site -
goto Hormonalfitness.
HGH Magazine.
Best HGH ? 10 best hgh supplements reviewed and ranked. "Fiber helps manage HGH, Insulin, and Cholesterol." "Potassium and HGH - What your doctor does NOT tell you." "Whey Protein Supercharges HGH Supplements."
Jamieson, James and Dr. L.E. Dorman. Growth Hormone: Reversing Human Aging Naturally. Published by J. Jamieson: St. Louis, MO, 1997.
Schuler, Lou. The Testosterone Advantage Plan. Rodale: USA, 2002.
Thorton, Jim. "Maximum Testosterone." Men's Health. April, 2005, pp. 146-155,182.