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Mobile app records our erratic eating habits

Satchidananda Panda

Breakfast, lunch and dinner? For too many of us, the three meals of the day go more like: morning meeting pastry, mid-afternoon energy drink and midnight pizza. In Cell Metabolism on September 24, Salk scientists presented daily food and drink intake data collected from over 150 participants of a mobile research app over three weeks. They showed that a majority of people eat for 15 hours or longer, with less than a quarter of the day's calories being consumed before noon and over a third consumed after 6 p.m.

The purpose of the app is to pilot a way to objectively study the effects of timing food intake in humans. Primed with evidence of how long people eat each day, senior author Satchidananda Panda—an associate professor in the Salk Institute's Regulatory Biology Laboratory—along with first author Shubhroz Gill, a former postdoctoral researcher, were able to test whether reducing this daily duration impacts health. In addition to cutting out some bad habits, the authors hypothesized that a timed feeding schedule could prevent "metabolic jetlag"—when differences in day-to-day or weekday/weekend meal times cause metabolic organs to become out of sync with the body's overall circadian rhythms.

Past experiments in mice from Panda's lab have shown that changing eating duration could protect against obesity and disease.

To begin to explore these implications in people, Gill and Panda designed a mobile app that could be used to collect, analyze and interpret patterns of food intake in humans. They kept the app simple, only requiring users to send pictures of everything they ate or drank, whether it was an entire water bottle or a few bites of a cookie. Each click also captured metadata (such as the location where food was consumed) and recorded a timestamp. Food data were not stored in the app, and reminders were sent about once a day to sustain compliance.

The data revealed cultural food practices, such as Americans' consumption of coffee and milk in the morning, alcohol in the evening, and tea throughout the day. Yogurt was a morning food, sandwiches and burgers were primarily reserved for lunchtime, while vegetables and ice cream were saved for the evening. Photos of chocolate and candy were recorded from pretty much 10 a.m. onward. Larger studies that collect data from patients, shift workers, and different socioeconomic groups will be necessary to offer a more complete picture and to study socio-economic variations.

The researchers also tested whether the app could assist people who wished to adapt to time-restricted feeding, for example, eating for fewer and consistent hours every day. Eight overweight individuals who used to eat for more than 14 hours every day were selected to eat for a 10—11 hour period each day without any recommendation for altering their normal diet. After 16 weeks, assisted by a weekly "feedogram" showing their dietary intake patterns, each lost an average of 3.5% of their excess body weight and reported feeling more energetic and having slept better.

"The study is about developing methods and offers some preliminary insight into what and when people eat," Panda says. "One should not take away the message that changing the eating duration is the only method to improve health. This may also be risky for individuals with undiagnosed fasting hypoglycemia."

The smartphone app is available for anyone willing to contribute his/her data to a Salk Institute IRB-approved study at www.mycircadianclock.org.