You are what you eat, as the adage goes. But a growing body of evidence indicates that it’s not just what and how much you eat that influence your health. How fast and when you eat also play a role.
Research now indicates that these two factors may affect the risk for gastrointestinal problems, obesity, and type 2 diabetes (T2D). Because meal timing and speed of consumption are modifiable, they present new opportunities to change patient behavior to help prevent and perhaps address these conditions.
Not So Fast
Most people are well acquainted with the short-term gastrointestinal effects of eating too quickly, which include indigestion, gas, bloating, and nausea. But regularly eating too fast can cause long-term consequences.
Obtaining a sense of fullness is key to staving off overeating and excess caloric intake. However, it takes approximately 20 minutes for the stomach to alert the brain to feelings of fullness. Eat too quickly and the fullness signaling might not set in until you’ve consumed more calories than intended. Research links this habit to excess body weight.
The practice also can lead to gastrointestinal diseases over the long term because overeating causes food to remain in the stomach longer, thus prolonging the time that the gastric mucosa is exposed to gastric acids.
A study of 10,893 adults in Korea reported that those with the fastest eating speed (< 5 min/meal) had a 1.7 times greater likelihood of endoscopic erosive gastritis than those with the slowest times (≥ 15 min/meal). Faster eating also was linked to increased risk for functional dyspepsia in a study involving 89 young-adult female military cadets in Korea with relatively controlled eating patterns.
On the extreme end of the spectrum, researchers who performed an assessment of a competitive speed eater speculated that the observed physiological accommodation required for the role (expanding the stomach to form a large flaccid sac) makes speed eaters vulnerable to morbid obesity, gastroparesis, intractable nausea and vomiting, and the need for gastrectomy.
Two clinical studies conducted in Japan — a cohort study of 2050 male factory workers and a nationwide study with 197,825 participants — identified a significant association between faster eating and T2D and insulin resistance. A case-control study involving 234 patients with new onset T2D and 468 controls from Lithuania linked faster eating to a greater than twofold risk for T2D. And a Chinese cross-sectional study of 7972 adults indicated that faster eating significantly increased the risk for metabolic syndrome, elevated blood pressure, and central obesity in adults.
Various hypotheses have been proposed to explain why fast eating may upset metabolic processes, including a delayed sense of fullness contributing to spiking postprandial glucose levels, lack of time for mastication causing higher glucose concentrations, and the triggering of specific cytokines (eg, interleukin-1 beta and interleukin-6) that lead to insulin resistance. It is also possible that the association is the result of people who eat quickly having relatively higher body weights, which translates to a higher risk for T2D.
However, there’s an opportunity in the association of rapid meal consumption with gastrointestinal and metabolic diseases, as people can slow the speed at which they eat so they feel full before they overeat.
A 2019 study in which 21 participants were instructed to eat a 600-kcal meal at a “normal” or “slow” pace (6 minutes or 24 minutes) found that the latter group reported feeling fuller while consuming fewer calories.
This approach may not work for all patients, however. There’s evidence to suggest that tactics to slow down eating may not limit the energy intake of those who are already overweight or obese.
Patients with obesity may physiologically differ in their processing of food, according to Michael Camilleri, MD, consultant in the Division of Gastroenterology and Hepatology at Mayo Clinic in Rochester, Minnesota.
“We have demonstrated that about 20%-25% of people with obesity actually have rapid gastric emptying,” he told this news organization. “As a result, they don’t feel full after they eat a meal and that might impact the total volume of food that they eat before they really feel full.”