The body of literature on the impact of food intake on GH is variable. Generally, carbohydrate decreases GH levels due to increases in glucose levels. Low blood sugar, on the other hand, appears to increase GH levels. Blood levels of fatty acids, which increase after a high fat meal, also tend to lower GH levels. Protein, and more specifically certain amino acids, seem to augment GH levels.
One amino acid that has received a lot of attention is arginine. When arginine is infused directly into a vein, GH levels increase dramatically. In fact, arginine infusion is used clinically as a diagnostic test when GH deficiency is suspected. With oral intake of arginine, the effects are less striking, but still, several studies show a significant increase in GH. The dose of arginine needed to increase GH levels appears to be at least 5 grams, with larger responses shown with 9 grams. Larger doses do not show a greater effect, indicating 9 grams is a threshold.
For perspective, exercise alone is a potent method to increase GH levels, even more so than arginine ingestion. Importantly, the effects of arginine and exercise are not additive. Thus, if you are considering trying arginine to boost GH, do it at some point removed from your exercise workout.
. van Vught AJ, Nieuwenhuizen AG, Brummer RJ, Westerterp-Plantenga MS. Effects of oral ingestion of amino acids and proteins on the somatotropic axis. J Clin Endocrinol Metab. 2008 Feb;93(2):584-90.
. Collier SR, Casey DP, Kanaley JA. Growth hormone responses to varying doses of oral arginine. Growth Horm IGF Res. 2005 Apr;15(2):136-9. Epub 2005 Jan 26.
. Collier SR, Collins E, Kanaley JA. Oral arginine attenuates the growth hormone response to resistance exercise. J Appl Physiol. 2006 Sep;101(3):848-52.