circadian rhythms

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You Are When You Eat: Study Explores Body Clock Effects On Blood Sugar

(Macro Mondays/Flickr Creative Commons)

(Macro Mondays/Flickr Creative Commons)

You know the old saying (or maybe you should): “Eat breakfast like a king, lunch like a prince and dinner like a pauper.”

A new study in the journal PNAS looks into some of the underlying biology: that our bodies tend to regulate blood sugar better after breakfast than after dinner.

Led by researchers at Brigham and Women’s Hospital, it also helps explain why night shift workers tend to be at heightened risk for Type 2 diabetes.

Says the study’s senior author, Frank A. J. L. Scheer of the Brigham, on Radio Boston today: “What we wanted to explore was whether the biological clock — the internal clock — is playing an important part in this day/night variation, or that it might just be due to the sleep/wake and feeding/fasting cycle.”

The study pinpoints two separate mechanisms at work:

• Our basic body clocks, also known as circadian rhythm, have major influence on our blood sugar regulation: our glucose tolerance is naturally higher in the morning than the evening.

• And, independently, when our clocks are misaligned — when we’re forced to flip our days and nights — that, too, lowers our glucose tolerance.

Bottom line, for those of us who are not shift workers: The same exact meal can lead to more of an increase in blood sugar when eaten at night than when eaten in the morning (and higher blood sugar is considered a risk factor for developing diabetes.) Chalk one up for the writers of old sayings.

On the study: Continue reading