Metabolic response to glucose ingested with various amounts of protein

Sydney A. Westphal, Mary C. Gannon, Frank Q. Nuttall

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Seven healthy, normal-weight subjects were fed breakfasts of 50 g protein, 50 g glucose, and 10, 30, or 50 g protein plus 50 g glucose in random sequence. Plasma glucose, insulin, C peptide, glucagon, nonesterified fatty acids, and α-amino nitrogen were then measured from samples obtained over 4 h. The postmeal net area of each response curve was calculated. Ingestion of 50 g protein alone did not change the serum glucose concentration. The various amounts of protein ingested with 50 g glucose also did not alter the serum glucose response compared with that observed with 50 g glucose alone. Ingestion of the various amounts of protein also did not result in a further increase in insulin concentration when ingested with glucose, except with the 50-g-protein dose. This increase was modest. Ingestion of glucose resulted in a decrease in α-amino nitrogen and glucagon concentrations whereas ingestion of protein increased them as expected. Additions of progressively larger amounts of protein to the glucose meal resulted in a progressive increase in the α-amino-nitrogen- and glucagon-area responses. The relationship was curvilinear for both the α-amino-nitrogen response and the glucagon response. The null point, that is, the protein dose ingested with 50 g glucose at which there would be no change in area response, was estimated to be 9 g protein for α-amino nitrogen and 5 g protein for glucagon.

Original languageEnglish (US)
Pages (from-to)267-272
Number of pages6
JournalAmerican Journal of Clinical Nutrition
Issue number2
StatePublished - Aug 1990


  • C peptide
  • Diet
  • Dietary protein
  • Glucagon
  • Glycemic index
  • Insulin
  • Relative glucose area
  • α-amine nitrogen


Dive into the research topics of 'Metabolic response to glucose ingested with various amounts of protein'. Together they form a unique fingerprint.

Cite this