myCircadianClock

Name: myCircadianClock
Author: Salk Institute for Biological Studies

Salk Institute for Biological Studies

CLINICAL GRADE

Validated in clinical trials

For:Researchers & Academics

Free

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App Summary

myCircadianClock is a research tool for study participants to log the timing of their diet, exercise, and sleep, enabling researchers to investigate the effects of daily rhythms on health. The associated research reveals that many people have erratic eating patterns spanning over 14 hours a day, and a study of overweight individuals found that shortening this eating window to 10-11 hours resulted in weight loss and improved sleep. Based on these findings, the authors conclude that tracking and modulating the timing of food intake can be a viable strategy for producing sustainable health benefits.

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Detailed Description

Functionality & Mechanism

myCircadianClock is a data collection platform developed for clinical research investigating circadian rhythms. The system captures longitudinal data on nutrition, sleep, and physical activity. Its core functionality facilitates the logging of all food and beverage intake via time-stamped photographs, reducing participant reporting burden. Additional modules capture sleep duration and exercise events. The platform visualizes dietary patterns for participants and researchers via a "feedogram," and integrates HealthKit data to provide a comprehensive view of daily behaviors for research analysis.

Evidence & Research Context

Research utilizing the app found that free-living adults often have erratic daily eating durations exceeding 14 hours, with over 35% of caloric intake occurring after 6 p.m.
A preliminary study documented that overweight individuals using the app to facilitate a 10–11 hour time-restricted eating window reduced body weight and reported improved sleep and energy.
In a small randomized trial (N=20) of adults with a BMI ≥25, the app was used to track intake, showing that a time-restricted eating intervention significantly reduced eating occasions and snack consumption.
The platform is designed as a research tool for capturing high-resolution, real-time temporal data on chrononutrition, addressing a key limitation of traditional dietary recall methods.

Intended Use & Scope

This platform is designed exclusively for use by clinical researchers and participants within approved studies. Its primary utility is as a research instrument for high-fidelity, longitudinal data collection on diet, sleep, and activity. The app is not a standalone health intervention or diagnostic tool and requires an activation code from a research coordinator to function.

Studies & Publications

3 publications

Peer-reviewed research associated with this app.

Development/Design Paper

Assessing temporal eating pattern in free living humans through the myCircadianClock app

Manoogian et al. (2022) · International Journal of Obesity

Describes the research-driven development of this app

The quality and quantity of nutrition impact health. However, chrononutrition, the timing, and variation of food intake in relation to the daily sleep-wake cycle are also important contributors to health. This has necessitated an urgent need to measure, analyze, and optimize eating patterns to improve health and manage disease. While written food journals, questionnaires, and 24-hour dietary recalls are acceptable methods to assess the quantity and quality of energy consumption, they are insufficient to capture the timing and day-to-day variation of energy intake. Smartphone applications are novel methods for information-dense real-time food and beverage tracking. Despite the availability of thousands of commercial nutrient apps, they almost always ignore eating patterns, and the raw real-time data is not available to researchers for monitoring and intervening in eating patterns. Our lab developed a smartphone app called myCircadianClock (mCC) and associated software to enable long-term real-time logging that captures temporal components of eating patterns. The mCC app runs on iOS and android operating systems and can be used to track multiple cohorts in parallel studies. The logging burden is decreased by using a timestamped photo and annotation of the food/beverage being logged. Capturing temporal data of consumption in free-living individuals over weeks/months has provided new insights into diverse eating patterns in the real world. This review discusses (1) chrononutrition and the importance of understanding eating patterns, (2) the myCircadianClock app, (3) validation of the mCC app, (4) clinical trials to assess the timing of energy intake, and (5) strengths and limitations of the mCC app.

RCT

Time-Restricted Eating Alters Food Intake Patterns, as Prospectively Documented by a Smartphone Application

Dong et al. (2020) · Nutrients

Time-restricted eating reduced eating occasions by 28% and decreased snacks and caffeinated beverages.

Time-restricted eating (TRE) can facilitate weight loss, yet its effect on eating patterns remains unknown. Twenty adults with BMI ? 25 kg/m2 underwent a 12-week randomized trial, examining the effect of an 8-h, time-restricted eating intervention on dietary patterns. Oral intake was documented using a smartphone. Dietary patterns, assessed as frequency of eating occasions (EOs) and types of meals/snacks and beverages, were compared between baseline (T0), early-intervention (T1), and end-intervention (T2). At T1 and T2, both groups had less EOs compared to T0, with greater reduction seen in the TRE group (?28%) than the non-TRE group (?12%) at T2 (p = 0.01 vs. non-TRE). Comparing T1 to T0, the TRE group documented less incomplete meals (?32.5%: p = 0.02), high quality snacks (?23.6%: p = 0.03), and low quality snacks (?36.6%: p = 0.004). Comparing T2 to T0, the TRE group documented less incomplete meals (?33.9%: p = 0.03), high quality snacks (?28.1%: p < 0.001) and low quality snacks (?51.2%: p < 0.001). Caffeinated beverage intake was reduced in the TRE group at T1 (?20.2%) and T2 (?28.8%) vs. T0, but remained unaltered in the non-TRE group. By using a smartphone application to document dietary intake, TRE significantly reduced the number of EOs, snacks, and caffeinated beverages, relative to baseline and relative to the non-TRE.

In the Media

Study: Time-Restricted Eating May Improve Health of Adults with Metabolic Syndrome

UC San Diego School of Medicine and the Salk Institute developed myCircadianClock to help patients with metabolic syndrome track their meals during a time-restricted eating study, using the mobile app to monitor customized 10-hour eating windows. All 108 participants in the TIMET clinical trial logged their meals using the myCircadianClock mobile app, which researchers then reviewed to ensure compliance with personalized eating schedules. The study demonstrated significant improvements in blood sugar, cholesterol, and hemoglobin A1c levels after three months of time-restricted eating.

UcsdRead article

Time-restricted eating improves health of firefighters

Salk Institute and UC San Diego Health developed myCircadianClock to improve cardiovascular health in shift workers, using time-restricted eating within a 10-hour window. "Our study showed that shift workers with high blood pressure, blood sugar, or cholesterol can benefit from a simple lifestyle intervention called time-restricted eating," says Salk Professor Satchidananda Panda. The clinical trial with San Diego Fire-Rescue Department firefighters demonstrated significant health improvements without adverse side effects.

SalkRead article

Clinical study finds eating within a 10-hour window may help stave off diabetes, heart disease

Salk Institute and UC San Diego researchers developed myCircadianClock to help metabolic syndrome patients manage their disease by implementing time-restricted eating within a 10-hour window combined with traditional medications. "Unlike counting calories, time-restricted eating is a simple dietary intervention to incorporate, and we found that participants were able to keep the eating schedule," says Satchidananda Panda, co-corresponding author from Salk's Regulatory Biology Laboratory. The pilot study published in Cell Metabolism found participants experienced weight loss, reduced abdominal fat, and improved blood pressure and cholesterol levels.

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Could when you eat be as important as what you eat?

Researchers have identified that the body's suprachiasmatic nucleus (SCN) serves as a central timekeeper that coordinates appetite and metabolism with natural 24-hour cycles, creating optimal eating times in the morning and early evening. The SCN works alongside secondary clocks in peripheral tissues and organs that respond to external cues called zeitgebers to regulate digestion, absorption and metabolic processes. Emerging evidence suggests that overriding this natural eating schedule can have severe consequences for health and weight management.

NewscientistRead article

Mobile app records our erratic eating habits - Salk Institute for Biological Studies

Salk Institute scientists developed myCircadianClock to objectively study the effects of timing food intake in humans, using a mobile research app to collect daily food and beverage intake data. The app revealed that over 150 participants ate for 15 hours or longer, with less than a quarter of daily calories consumed before noon and over a third after 6 p.m. Researchers used this data to test whether reducing daily eating duration could prevent "metabolic jetlag" and improve health outcomes.

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