Is eating meals at irregular times unhealthy?

Question

Best Time to Eat Meals

Skipping meals or eating meals on a random schedule can drain your body of energy

I tend to eat whenever I feel like it. I pretty much ignore breakfast, lunch, and dinner times. Is this unhealthy, as opposed to eating a set number of times per day at set times, and why? My parents tell me "it's healthier" to eat during set times of the day.

Answer 1

I thought that we would have evolved with irregular meal-times, and the evidence would demonstrate the desire for regular meal-times was an "old wive's tale". I was surprised by the evidence, which does support the idea of regular meal-times.

Energy after Eating

• H R Farshchi, M A Taylor and I A Macdonald, Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women, International Journal of Obesity (2004) 28, 653–660. doi:10.1038/sj.ijo.0802616

Nine lean women were given regular meals and irregular diet with up to 9 meals per day.

CONCLUSION: Irregular meal frequency led to a lower postprandial energy expenditure compared with the regular meal frequency, while the mean energy intake was not significantly different between the two. The reduced TEF with the irregular meal frequency may lead to weight gain in the long term.

(Note: The last sentence is speculation. They did not observe weight-gain during the trial.)

The same authors tried it again with obese women:

• Hamid R Farshchi, Moira A Taylor, and Ian A Macdonald, Beneficial metabolic effects of regular meal frequency on dietary thermogenesis, insulin sensitivity, and fasting lipid profiles in healthy obese women, Am J Clin Nutr January 2005 vol. 81 no. 1 16-24.

Ten obese women were put on regular and irregular meal times for two weeks:

Conclusion: Regular eating has beneficial effects on fasting lipid and postprandial insulin profiles and thermogenesis.

Some other studies show some less directly related, but still interesting, results:

In Your Head

• This study shows that "dinner time" hunger may be more about what time your head thinks it is, rather than the state of your stomach.

Regular Family Meals

• Related to the idea of regular meals, is the idea of regular family meals. There are a number of positive social effects related to regular family meals.

• In Finnish children, not having a regular family dinner is correlated to eating more sweets, more problematic behaviour and a lower socio-economic class. I would tentatively suggest the causation is more likely to flow from the socio-economic class towards the other items.

• In Minnesotan children, regular family meal times was associated with healthier eating five years later. Again, I suspect socio-economic class and education to be a confounding factor. (Same authors)

Meal Frequency - Nibbling versus Gorging

Just because you have regular meal times, doesn't mean there aren't a lot of them throughout the day.

• Increased frequency (with the same total intake) may reduce cholesterol.

• Increased frequency may affect insulin secretion.

• However, this study argues some of the weight-loss claims associated with increased frequency eating may be experimental artefacts.

• Increased frequency eating helps athletes consume high-calory diets