SwissChronoFood - Study of eating patterns with a smartphone app and the metabolic effects of time restricted feeding in metabolic syndrome

The purpose of this study is to assess eating patterns among teenagers and adults with a new method, going beyond the pen-and-paper food diaries, and to investigate whether time restricted feeding leads to weight loss, improvement in lipid and glucose metabolism in individuals with components of the metabolic syndrome

The prevalence of the metabolic syndrome (MS) is increasing worldwide, due to the progression of its different components (central obesity, elevated blood pressure, impaired glucose tolerance and dyslipidemia), as well as the often associated liver steatosis. One way to tackle the obesity epidemic is to intervene early at the onset in childhood and teenage years - before cardio-metabolic complications have occurred. However, lifestyle programs targeting this age group had limited success in the current obesogenic environment. In particular, weight loss is a key factor in controlling all MS components, yet it is difficult to maintain over time.

Time restricted feeding (TRF) is an approach that emphasizes energy intake limited to certain windows of time within the 24-hour cycle without restrictions on calories or macronutrients. This has emerged as an appealing approach to reduce body weight while improving lipid profile and glucose metabolism. However, TRF has been mostly studied in animals and long-term prospective data on its efficacy and mechanisms in humans is lacking.

Prior to the intervention, the investigators will assess the eating patterns of participants with an innovative smartphone application ('app') which is less intrusive and more reliable than food diaries/questionnaires to assess eating behavior and patterns.

In this project, the investigators will assess eating patterns among teenagers and adults, and investigate whether a controlled TRF intervention leads to beneficial changes in MS components. Study Part 1 uses an epidemiological approach to establish baseline daily eating behavior, physical activity patterns and sleeping habits over 2 weeks (teenagers) and 4 weeks (adults) using the smartphone app. Those individuals meeting criteria for at least one component of MS and who have eaten for >14 hours per 24-hour cycle will be recruited for Study Part 2. In Part 2, participants will be assigned to TRF or active control groups, and followed in this pragmatic randomized controlled trial for 6 weeks (teenagers) and 6 months (adults) to assess the change in their weight and MS components, as well as liver fat deposits. Study Part 3 will investigate the underlying mechanisms of improved metabolic profile with TRF.

Key inclusion criteria for both observation and intervention phases (Part 1+2):

• Age ≥ 12 years
• Body mass index ≥ 20 kg/m2 and stable weight (previous 3 months) in adults; BMI ≥ 25th percentile in teenagers
• Smartphone compatible with the app (iOS or Android systems)

Additional inclusion criteria for the intervention phase (Part 2):

• Any component of the metabolic syndrome following the International Diabetes Federation consensus definition
• Eating duration >14h during the observation phase

Additional inclusion criteria for the mechanistic study (Part 3):

• Age 18-40 years, men and pre-menopausal women
• BMI 30-40 kg/m2
• In the fasting state (at least 8 hours)

Key exclusion criteria for both observation and intervention phases (Part 1+2):

• Pregnant and breastfeeding women, plans for maternity during the study
• Major illness/fever over the previous month, active cancer
• Eating disorder, on a diet / weight management, prior bariatric surgery
• Major mental illness, unable to give informed consent
• Current shift work or travel abroad planned in the next month

Additional exclusion criteria for the intervention phase (Part 2):

• Prior cardiovascular event
• Major liver, gastrointestinal, renal or endocrine disorder, diabetes mellitus with hypoglycemic drug(s)
• Major sleep disorder, centrally acting medication
• Lipid lowering drug, hypoglycemic drug, medication affecting the gut

Additional exclusion criteria for the mechanistic study (Part 3):

• Impaired glucose tolerance (pre-diabetes) or diabetes mellitus
• Positive pregnancy test

Anonymized dataset of selected variables that underlie results in a publication. Some data may not be amenable to complete anonymization and will not be shared to ensure appropriate confidentiality of participant's data.

Starting 6 months after publication

Upon appropriate data request by other scientists