Time-Restricted Eating vs Calorie Restriction for Depression and Obesity RCT
A 24-week RCT protocol tests whether an 8-hour eating window can ease depression severity and metabolic markers in obese adults with MDD.
Summary
Depression and obesity frequently co-occur, yet most dietary interventions target weight alone. This Iranian trial will enroll 90 obese adults diagnosed with major depressive disorder and randomly assign them to one of three 24-week interventions: time-restricted eating with an 8-hour window, that same eating window combined with a 25% calorie cut, or calorie restriction alone. The primary outcome is change in depression severity, with secondary measures covering body composition, blood sugar control, lipid levels, insulin resistance, blood pressure, circadian rhythm scores, and quality of life. Results could clarify whether the timing of meals — independent of calories — meaningfully affects mood and metabolic health, opening new dietary strategies for clinicians managing patients who carry both diagnoses simultaneously.
Detailed Summary
Depression and obesity form a bidirectional, mutually reinforcing relationship that burdens millions of patients and strains health systems globally. Yet dietary guidelines for these patients rarely address both conditions together. This trial, registered on the Iranian Clinical Trials Registry, sets out to fill that evidence gap directly.
The study will recruit 90 obese adults with confirmed major depressive disorder (MDD) and follow them for 24 weeks at a single center. Participants are randomized equally into three arms: a fixed 8-hour time-restricted eating (TRE) window with no explicit calorie target, TRE plus a 25% calorie reduction, and traditional 25% calorie restriction alone. Random allocation is 1:1:1, and the trial is single-blinded.
The primary outcome is change in depression severity score — a relatively novel endpoint for a dietary intervention trial. Secondary outcomes are comprehensive: body weight, BMI, waist circumference, fat mass, fat-free mass, fasting glucose, serum insulin, HbA1c, HOMA-IR, lipid panel, blood pressure, circadian rhythm score, physical activity, and quality of life. This breadth allows the team to disentangle metabolic from mood-related effects.
The rationale is compelling: calorie restriction reliably promotes weight loss but shows inconsistent effects on mood and is notoriously hard to sustain long-term. TRE aligns food intake with circadian biology and has demonstrated metabolic benefits in prior studies, but its psychiatric effects are largely unexplored. Pairing TRE with formal calorie restriction in a third arm lets the investigators test whether timing or quantity of food is the more potent driver of any observed improvements.
Findings from this trial could reshape integrated management of obesity and depression, potentially offering clinicians a non-pharmacological tool that addresses both conditions simultaneously. Confidence is tempered by the protocol-only nature of the publication — no outcome data yet exist.
Key Findings
- Trial tests whether an 8-hour eating window alone can reduce depression severity in obese adults with MDD over 24 weeks.
- Three-arm design isolates the effects of meal timing vs. calorie restriction vs. both combined.
- Primary endpoint is depression score, not weight — a rare choice for a dietary intervention study.
- Secondary outcomes include HbA1c, insulin resistance, lipid profile, circadian rhythm score, and quality of life.
- Results could provide a non-pharmacological strategy targeting obesity and depression simultaneously.
Methodology
Single-center, single-blinded, prospective RCT enrolling 90 obese adults with major depressive disorder, randomized 1:1:1 across 24 weeks. Three arms compare TRE alone (8-hour window), TRE plus 25% calorie restriction, and 25% calorie restriction alone. The trial is registered on the Iranian Clinical Trials Registry (IRCTID: IRCT20241029063543N1).
Study Limitations
This is a study protocol publication only — no outcome data are available yet, so no efficacy conclusions can be drawn. The summary is based on the abstract alone, as the full text was not accessible. Single-center recruitment in Iran may limit generalizability, and single-blind design introduces potential for performance bias.
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