In our society, grazing and eating small, frequent meals has become standard practice.

But did you know that snacking comes with a cost?  Eating between meals interferes with the process of digestion. Let me tell you about the physiology of digestion, specifically about the Migrating Motor Complex.

What is the Migrating Motor Complex?

Simply put, the Migrating Motor Complex (MMC)  is the housekeeper of the small intestine, sweeping bacteria, indigestible food remnants, and debris into the large intestine.

It starts automatically when no food is in the stomach. About two to three hours after eating, the stomach and small intestine are mostly empty. Then the MMC can start. A cyclical, recurring sweeping action flows through the stomach and small bowel.

Did you catch that? The MMC can only do its housekeeping when the stomach is empty.

What Makes Your Stomach Rumble

When functioning adequately, this cleansing process occurs every 90 to 120 minutes when there is no food in the stomach—about three hours after eating and while sleeping. There are four phases to each cycle:

  • Phase 1: little or no activity—resting
  • Phase 2: increased frequency and strength of contractions
  • Phase 3: most active phase with the strongest contractions and the most movement as it sweeps through about 23 feet of small intestine. This is what makes your stomach rumble.

What Interrupts the MMC

The cleaning cycle repeats until interrupted by:

  • food entering the stomach—which happens often in our society of grazers
  • stress—why it’s important to stay out of the fight-or-flight mode and stay in the rest-and-digest mode as much as possible.

When the MMC is Impaired

Have you ever ended up with moldy smelling laundry because bacteria grew in the dampness of a front-loading washing machine?

Something similar can happen in the body. When the cleansing cycle of the MMC is impaired or interrupted, bacterial overgrowth can happen in the small intestine. In the body, small intestine bacterial overgrowth (SIBO) can occur and cause troublesome gastrointestinal symptoms, such as:

  • Abdominal bloating or pain
  • Feeling like food is just sitting in the stomach
  • Heartburn, nausea, burping
  • Constipation or diarrhea

Embrace the Space Between Meals

In order to optimize the 90-minute cleansing process of the MMC and allow the stomach a chance to rest before the next meal, begin to embrace the space between meals. Work up to spacing meals five to six hours apart. It will take time to adjust to a longer span between meals, but your stomach will thank you.  Your mother was right–don’t eat between meals.



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Ohno, T. & Mochiki, E. & Kuwano, H. (2010). The roles of motilin and ghrelin in gastrointestinal motility. International Journal of Peptides.

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Romanski, K. (2009) Characteristics of the migrating motor complex in man and animals. Journal of the Faculty of Veterinary Medicine, Kafkas University. 15 (2): 315-322. DOI:10.9775/kvfd.2009.037-D

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For Additional Information:

Small Intestine Bacterial Overgrowth website by Allison Siebecker, MD