336 Adults Show Lower Depression and Anxiety Scores After 4 Weeks of Dawn-to-Dusk Fasting: What the Research Shows

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

Study at a Glance

What This Study Looked At

Researchers wanted to know whether a full month of dawn-to-dusk intermittent fasting — the pattern followed during Ramadan, with no food or water from before sunrise until sunset — measurably changes mental health and cognitive function in otherwise healthy adults. Rather than relying on how people said they felt in general terms, the study used two of the most widely validated psychiatric screening tools in clinical research: the PHQ-9 for depression symptoms and the GAD-7 for anxiety symptoms. This adds useful data to a broader question people often ask about does intermittent fasting improve mood, using standardized clinical scales rather than informal self-report.

Who Was Studied

Participant profile: The cohort was predominantly male (84.2%). Participants were assessed at two time points: before the fasting month began, and again during the final week of the four-week fasting period.

How the fasting protocol worked: Dawn-to-dusk fasting means abstaining from all food and water from before sunrise until sunset each day, for approximately 29-30 consecutive days. This is a stricter protocol than most Western time-restricted eating approaches, which typically permit water and non-caloric beverages throughout the fasting window.

What the Researchers Found

Depression Symptoms (PHQ-9)

• The proportion of participants classified with minimal or no depression increased from 21.4% to 38.1% over the four weeks.
• This represents a statistically significant reduction in depressive symptom burden across the cohort.

Anxiety Symptoms (GAD-7)

• Anxiety scores dropped significantly alongside the depression score improvements.

Quality of Life and Sleep

• Quality of life scores increased significantly (p < 0.010) over the fasting period.
• Sleep quality, measured with the Pittsburgh Sleep Quality Index (PSQI), improved significantly (p = 0.014).

What Did Not Change

• Diet quality, measured using the KIDMED index, did not show a substantial improvement over the fasting period — meaning the mental health gains were not simply explained by participants eating a healthier diet overall.

What the Researchers Concluded

The authors concluded that four consecutive weeks of dawn-to-dusk intermittent fasting were associated with meaningful improvements in depression and anxiety symptoms, along with better self-reported quality of life and sleep, in this adult cohort — supporting a possible role for structured fasting patterns in supporting mental well-being.

What This Means If You Fast

• A full month of consistent fasting showed real, measurable shifts on standardized clinical mental health scales — not just informal "I feel better" reports.
• The improvement happened without a corresponding jump in diet quality, suggesting the fasting pattern itself, and not simply eating healthier food, played a role in these results.
• Sleep and mood may move together. The improvement in PSQI sleep scores alongside PHQ-9 and GAD-7 improvements fits with what's known about the link between fasting, circadian rhythm, and mental health — see does intermittent fasting affect sleep for more on that connection.
• This is dawn-to-dusk fasting, not typical Western time-restricted eating. Most 16:8 or 18:6 protocols allow water and non-caloric drinks throughout the fast, which is a meaningfully less restrictive pattern than the one studied here.
• Individual results vary. Cohort averages don't guarantee every individual will experience the same improvement, and anyone with a diagnosed mood disorder should coordinate any fasting practice with their treating clinician.

Study Limitations

• This is a prospective cohort study without a non-fasting control group, so the observed changes cannot be fully separated from other factors that occur during Ramadan, such as changes in social routine, sleep timing, or religious and community context.
• The sample was heavily skewed male (84.2%), which limits how well the findings generalize to women.
• The study measured symptoms at only two time points (before and during the final week), so it can't say how quickly the changes occurred or whether they persist after the fasting period ends.
• Full numerical data on secondary measures like resilience scores were not independently verifiable at the time of writing due to database access restrictions.
• Funding source was not reported in the available sources.

Source

Faris ME, Abdelrahim DN, et al. (2026). Four consecutive weeks of dawn-to-dusk intermittent fasting are associated with improved neuropsychiatric symptoms and neurocognitive functions among adults: a prospective cohort. BMC Complementary Medicine and Therapies. PMC13014878

Frequently Asked Questions

Does intermittent fasting reduce depression symptoms?

In this study of 336 adults, average PHQ-9 depression scores dropped significantly from 8.89 to 7.28 after four weeks of dawn-to-dusk intermittent fasting (p < 0.001), and the share of participants with minimal or no depression rose from 21.4% to 38.1%.

Does intermittent fasting help with anxiety?

Yes, in this study — average GAD-7 anxiety scores fell significantly from 7.39 to 5.75 over the four-week fasting period (p < 0.001).

Was this study a randomized controlled trial?

No, it was a prospective cohort study without a non-fasting control group, so it can show association but not definitively prove that fasting alone caused the improvements.

Did better diet explain the mental health improvements?

Not according to this study — diet quality scores (KIDMED) did not show a substantial improvement, suggesting the fasting pattern itself, not just healthier eating, was linked to the mood and anxiety changes.

Is dawn-to-dusk fasting the same as a typical 16:8 intermittent fasting protocol?

No. Dawn-to-dusk fasting restricts both food and water for around 12-16 hours depending on season and location, while most Western intermittent fasting protocols like 16:8 allow water, herbal tea, and black coffee throughout the fasting window.

Related Research and Articles

• Does intermittent fasting improve mood?
• Does intermittent fasting help with depression?
• Can fasting cause anxiety or irritability?
• Does intermittent fasting affect sleep?
• Does intermittent fasting improve focus and mental clarity?
• Is intermittent fasting dangerous?

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