Metabolic syndrome is a cluster of risk factors, including abdominal obesity, high blood pressure, high triglycerides, and insulin resistance, that increase the risk of developing type 2 diabetes and cardiovascular disease. The prevalence of this syndrome is rising in Mexico. Recent research suggests that when we eat is as important as what we eat. Therefore, chrononutritional strategies such as time-restricted eating (TRE), where food intake is confined to a specific daily time window, have been developed and shown promising benefits. However, there are documented barriers to maintaining this nutritional strategy over time. Therefore, this study proposes that combining TRE with a psychochrononutritional program (integrating psychological, chronobiological, and nutritional components) will improve adherence to the nutritional strategy and lead to better health outcomes than only prescribing a specific eating window.
To this end, 64 adults (18-60 years old) with metabolic syndrome will be recruited in Ciudad Guzmán, Jalisco, Mexico. The TRE intervention will last eight weeks and include two groups. One group will undergo a psychochrononutritional intervention, whereas the other will receive only instructions regarding the eating window. Within each group, two subgroups will be formed: one assigned to an 8-hour eating window, and the other to a 10-hour window. Before and after the intervention, anthropometric, biochemical (lipid profile and plasma glucose), clinical (blood pressure), and dietary assessments will be performed. We expect reductions in blood pressure, glucose, triglycerides, and waist circumference as well as better adherence in the psychochrononutritional intervention group.
Age 18 to 60 years
Both sexes
Feeding window ≥14 h/day
Usual sleep duration >6.5 h
(based on participant self-report unless medical records are available)
Pregnancy or lactation
Currently enrolled in a weight loss program
Current treatment with antidepressants, medications that affect glucose metabolism or appetite, or immunosuppressant therapy
Parallel
Time restricted eating
BehavioralBehavioral and dietary intervention in which participants are instructed to consume all their food and caloric beverages within a fixed window (8 or 10 hours, depending on arm assignment). Outside of this window, only water or non-caloric beverages are permitted. The intervention will last 8 weeks.
Psychochrononutritional intervention
BehavioralParticipants will receive a structured psychochrononutritional intervention consisting of eight weekly sessions. The program will cover the following topics: * Chrononutrition: The internal clock of eating. * Food groups and healthy menu planning. * Portion control: Learning to measure appropriately. * Effects of sugary drinks. * Sleep and its impact on eating habits. * Social and cultural factors in eating habits. * The relationship between physical activity and nutrition. * Making informed nutritional decisions.
Waist circumference
Waist circumference: A decrease in waist circumference is expected, ≤102 cm in men and ≤88 cm in women. Measured in centimeters using a measuring tape at the level of the navel, at the end of a normal exhalation.
Changes in Blood Pressure
Blood Pressure: A decrease in blood pressure of ≤130/85 mmHg is expected. Measurement of systolic and diastolic blood pressure using a digital blood pressure monitor.
Changes in Glucose
Glucose: A decrease in glucose level to \<110 mg/dL is expected. Measurement of fasting plasma glucose, measured through a venous blood sample obtained between 7:30 and 8:30 am and processed using an automated colorimetric method.
Changes in HDL cholesterol
HDL cholesterol: An increase in its values is expected, with a normal range of \>40 mg/dL in men and \>50 mg/dL in woman. The increase will mean better cardiovascular outcomes. Measurement of HDL cholesterol measured through a venous blood sample obtained between 7:30 and 8:30 am and processed using an automated colorimetric method.
Changes in Body weight
Body weight: An average reduction of 10% in initial body weight is expected at the end of the intervention. Measurement in kilograms using a digital scale. The participant should be barefoot, wearing as little clothing as possible, and preferably fasting.
Body composition analysis
It will be evaluated by electrical bioimpedance (InBody®), comparing the baseline measurement with the final measurement at week 8. A healthy body fat percentage will be taken as a reference point: ≤25% in women and ≤15% in men. Por otro lado, a healthy body muscle considering an increase in relation to healthy reference values: ≥35% in men and ≥25% in women.
Changes in visceral fat
Changes in visceral fat measurement performed by electrical bioimpedance (InBody®).
Mexican Diet Quality Index
The Mexican Diet Quality Index (IACDMx) will be applied, which classifies foods and beverages into 13 groups. One point is assigned to each component if its energy percentage meets the recommendation. The food classification and cut-off points are based on the energy percentage, considering the energy intake recommendation for each group, in relation to the total daily energy intake of 2,500 kcal proposed by the commission. The score is grouped into five categories: ≤5, 6, 7, 8, and ≥9 points.
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