Healthy Aging Through Time- Restricted Eating in Adults With Overweight/Obesity and Incipient Liver Disease: ENSATI

The goal of this clinical trial is to evaluate the effect of a time-restricted eating (TRE) regimen on hallmarks of aging, in comparison with traditional caloric restriction and an unrestricted diet in adults with overweight/obesity.

Investigators aim to assess:

1. If TRE is sustainable over 6-months.
2. If TRE positively affects metabolism and body composition
3. If TRE improves circadian rhythm/sleep.
4. If TRE benefits cognitive function, mood and quality of life (QoL).
5. If these beneficial effects are associated with changes in molecular hallmarks of aging.

Participants will be randomly allocated to:

* an unrestricted Mediterranean diet group (MedD)
* a energy-reduced Mediterranean diet group (MedD_RC)
* or to an unrestricted Mediterranean diet with TRE group (MedD_TRE)

Intervention will be maintained for 6 months, and there will be an additional 6-months period of follow-up to assess the maintenance of the intervention without supervision.

Changes from baseline in phenotypic and molecular hallmarks of aging, including: chronobiology, quality of life, cognition, metabolism and epigenetics among groups over the follow-up will be analyzed.

Aging has been defined as the time-dependent functional decline that affects most living organisms, and this biological process occurs with great variability from person to person. Healthy aging refers to developing and maintaining functional abilities to enable the well-being of the elderly. Therefore, promoting healthy aging strategies in the population would result in people living in a healthy state for most of their lifespan. This would have an important socio-economic impact, considering that aging is a risk factor for multiple diseases and that the proportion of older persons continues to increase. Interestingly, healthy lifestyle habits such as proper nutrition and physical exercise could attenuate the progression of aging-related diseases and ameliorate age-related decline. Among the lifestyle interventions that could improve healthspan, time restricted eating (TRE) is a promising candidate. TRE is a type of intermittent fasting that involves time-limited consumption of food during a specific time window. This dietary intervention has a demonstrated positive impact on some aspects of health both in pre-clinical models and clinical trials. The beneficial effects of TRE can occur at different physiological levels that are related to healthy aging, such as metabolism and body composition, circadian rhythms and sleep, and cognitive function. However, the mechanisms through which TRE may influence these aspects are not fully understood. Therefore, and considering current evidence pointing to a beneficial effect of TRE on health, the hypothesis is that an intervention with TRE in overweight/obese individuals has a positive impact on their aging determinants (metabolism and body composition, circadian rhythms and sleep, quality of life, and cognitive function) which is associated with favorable changes in cellular traits of aging (autophagy, immunosenescence, and biological age). This is a controlled, randomized, parallel group intervention trial to assess the effect of TRE, in comparison with traditional caloric restriction and unrestricted diet on phenotypic and molecular aging parameters.

Eligibility Criteria:
Inclusion Criteria:

* BMI: 27-35 Kg/m2
* Prevalent fatty liver disease (FLI \> 59 or echography screening) EASL, Clinical Practice Guidelines for the management of non-alcoholic fatty liver disease, 2016.
* Habitual daily eating window ≥ 14 h
* Regular sleeping patterns (7 ± 2 sleeping hours every day)
* Stable weight during the last 3 months (weight changes ≤ 4 Kg)
* Not considering changes in thei physical activity in the following 6 months
* Not being under a weight-loss program or medication.

Exclusion Criteria:

* Non-menopausal women
* Alcohol abuse (CAGE score \> 2, Ewing, 1984; Malet et al. 2005)
* Change in smoking habits in the previous 6 months.
* Prevalent renal, cardiovascular, liver (excluding fatty liver), endocrine o pancreatic disease.
* Type 1 diabetes
* Type 2 diabetes with poor glucose control.
* Poorly control hypertension.
* Medical treatment affecting weight or sleep.
* Food allergies or intolerances affecting the adherence to the intervention.
* Eating disorders.
* Shift workers.
* Participants of other studies.
* Social factors affecting to the adherence to the intervention (being institutionalized, unable to ingest solid food).