When’s Mealtime?

Mealtime matters. It matters to people with grumbling stomachs, as well as this pup, but it also matters for regulation of your body weight. A new study in the International Journal of Obesity finds that the timing of a meal can have a big effect on your metabolism and thus potentially on your weight.

In two randomized crossover-controlled trials, Marta Garaulet and colleagues tested the metabolic effects of eating an early lunch at 1:00 (this was in Spain) or a late lunch at 4:30. Everyone in the studies got standardized meals for breakfast, lunch, and dinner, and everyone followed each schedule for a week. In one study, the endpoints were metabolic — measures like resting energy expenditure and glucose tolerance. In the other, they were measures related to circadian rhythm — like salivary cortisol and wrist temperature.

They found significant reductions in resting energy energy expenditure, glucose tolerance, and other indicators of metabolic activity when people ate the late lunch. They found that the late lunch significantly altered markers for circadian rhythm. In other words, eating a late lunch appears to slow down your metabolism and put your body into a state of conserving energy.

Sorting out the effects of different timings and sizes of meals can quickly morph into a problem of bewildering complexity. Don’t even get us started on the arguments about skipping breakfast. People who offer glib advice about the ideal eating regimen should be heard with caution.

But it’s worth figuring out what works for you, perhaps with the help of a good dietitian.

Click here to read the study of early versus late lunch times. Click here to read a recent study of the effect of meal timing on daily caloric intake.

mmmmm suppertime, photograph © judith whelan / flickr

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