Hunger contraction are peristaltic contraction that approach titanic contractions for periods of about 2-3 minutes. Low blood glucose levels create the contractions to increase and become sufficiently strong to create uncomfortable sensations called hunger pangs. Hunger pangs usually begin 12-24 hours after a meal or in less time for some people. If nothing is ingested, they reach their maximum intensity within 3-4 days and then become progressively weaker.