# Ramadan fasting and weight: what the studies show

October 8, 2026 · Eating Patterns & Timing · 8 min read · https://burnweek.fit/blog/ramadan-fasting-and-weight/

> Three meta-analyses, thousands of people, one pattern: about a kilogram goes, then much of it comes back within weeks. The clock changes more than the plate.

**Key takeaways**

- Pooled studies show about 1.0–1.3 kg lost on average by the end of Ramadan, larger in people starting with a higher BMI.
- Much of it returns within 2–5 weeks; one review still found weight about 0.6 kg below the pre-Ramadan level then.
- Reported intake falls only about 142 kcal a day across 80 studies; the review's authors point to meal timing over quantity.
- Sleep drops by roughly an hour a night during Ramadan, from about 7.2 to 6.4 hours in pooled studies.
- Reviews differ on whether longer daily fasting predicts more weight loss.

## Average weight falls by about a kilogram during Ramadan, and much of it returns within weeks

Does Ramadan fasting make you lose weight, and does the weight stay off afterward? Three meta-analyses of overlapping research, covering thousands of healthy adults, report an average loss of roughly 1 to 1.3 kg by the end of the month. The two that followed people afterward agree on the second half of the answer: within about two to five weeks after Eid, most of that loss returns, though one found weight still about 0.6 kg below the pre-Ramadan level.

That pattern is remarkably consistent for a body of research spread across dozens of countries, seasons and decades. It is also easy to misread in both directions. Ramadan is not a weight-loss diet, and the largest review excluded studies that deliberately changed participants' diet or activity; the modest loss comes alongside a changed eating schedule. And the regain is not a failure of willpower; it is what you would expect when the schedule ends and the old one resumes. This article covers what was measured, why the loss is small, why it reverses, and how to keep an eye on the numbers if you want to — without offering any advice on the fast itself, which is a religious practice and not ours to shape.

If you came here from the broader [intermittent fasting guide](/blog/intermittent-fasting), the key difference is this: Ramadan is a dawn-to-sunset fast with no food or water for the whole daylight period, repeated for about 29 or 30 days, with all eating moved into the night.

## Three meta-analyses, one consistent number

Three pooled analyses asked slightly different questions, but they land in the same place.

| Meta-analysis | Studies and people | Weight change by end of Ramadan | What happened after |
|---|---|---|---|
| [Sadeghirad et al., 2014](https://pubmed.ncbi.nlm.nih.gov/23182306/) | 35 studies, healthy adults | −1.24 kg (95% CI −1.60 to −0.88); men −1.51 kg, women −0.92 kg | Most regained within a few weeks; loss lasted no longer than 2 weeks after Ramadan |
| [Fernando et al., 2019](https://pubmed.ncbi.nlm.nih.gov/30813495/) | 70 publications, 2,947 people | −1.34 kg (95% CI −1.61 to −1.07); larger the higher the starting BMI | At 2–5 weeks after: −0.59 kg vs before Ramadan; body composition back to baseline |
| [Jahrami et al., 2020](https://pubmed.ncbi.nlm.nih.gov/32157368/) | 85 studies, 4,176 people in 25 countries | −1.02 kg (95% CI −1.16 to −0.88); Hedges' g −0.36 | Not the focus of this analysis |

A difference of about a kilogram over a month is small next to normal day-to-day scale noise, which is why a single weigh-in on the last day of the month says little on its own (the [guide to scale fluctuations](/blog/why-the-scale-fluctuates) explains why a kilogram can move overnight).

Two details from these analyses matter for interpreting your own experience.

**Who loses more.** Fernando and colleagues found a significant positive correlation between starting body mass index and weight lost. Body-fat percentage fell by 1.46 percentage points (95% CI −2.57 to −0.35) in people with overweight or obesity, but not significantly in people of normal weight (−0.41; 95% CI −1.45 to 0.63). One disclosure from that paper, for completeness: its senior author reported past payments from pharmaceutical companies and service on a meal-replacement advisory board.

**What else is lost.** The same review found that fat-free mass also dropped significantly — by about 30% less than fat mass. So part of the lost kilogram is not fat at all; it includes lean tissue and, very likely, water and gut contents that shift whenever the eating pattern changes.

**How long the fast is each day.** Jahrami's meta-regression found that fasting time in minutes per day was a significant moderator of weight change, with no significant moderation by age or sex; Fernando's review, however, found no significant link between scheduled fasting duration and weight change, so the reviews differ on this point. Ramadan follows the lunar calendar, so it drifts through the seasons; a summer Ramadan at high latitude means far longer fasting days than a winter one near the equator. Studies from different years and places may, in a real sense, be studying different fasts.

> Ramadan's weight change arrives with the calendar, not with a diet — and for most people, much of it leaves with the calendar too.

## Reported intake falls by only about 140 calories a day

Why is the loss so small when people go without food for 12 to 18 hours a day? Because the food is not skipped; it is moved.

A synthesis of dietary intake during Ramadan reviewed 85 studies (participants aged 9 to 85). In the 80 studies and 3,343 people with energy data, intake fell by an average of 142 kcal per day (95% CI −215 to −70), with carbohydrate down about 24 g and protein down about 4 g; fat intake did not change significantly ([Abdelrahim et al., 2024](https://pubmed.ncbi.nlm.nih.gov/37986623/)). The authors concluded that the change in meal *timing*, rather than the quantity eaten, may explain most of the physiological effects associated with the fast.

Lower reported intake is not the same as a measured energy deficit, since expenditure can change too. If this reduction did create an equivalent deficit, the rough arithmetic (ours, not the paper's) would be 142 kcal × 29 days ≈ 4,100 kcal, or about half a kilogram at the common approximation of 7,700 kcal per kilogram of fat.

The width of the confidence interval matters too: the pooled reduction could plausibly be as small as 70 kcal or as large as 215 kcal a day. And those are averages across very different food cultures. The pre-dawn meal (suhoor) and the sunset meal (iftar) can easily add up to less than a normal day for one person and considerably more for another.

## Shorter nights change the picture as well

The fast does not only move meals; it moves sleep. A meta-analysis of sleep during Ramadan (24 studies; 22 studies and 571 people for sleep duration) found total sleep time fell from about 7.2 hours per night before Ramadan to about 6.4 hours during it — roughly an hour less — while daytime sleepiness scores rose only slightly ([Faris et al., 2020](https://pubmed.ncbi.nlm.nih.gov/31832984/)).

That matters for weight in a less obvious way. Late-evening meals, a pre-dawn meal and shortened sleep are the conditions that research on [late-night eating](/blog/late-night-eating-and-weight) and on sleep loss studies in isolation. During Ramadan they arrive together, for a month, and then leave together. Participants were predominantly male (73%), with a median age of about 24, so how well the one-hour figure transfers to older adults, parents of small children or shift workers is uncertain.

## Why the kilogram comes back

None of the three meta-analyses was designed to test *why* weight returns. Changes in intake, activity and body water could all contribute; these reviews do not establish their relative contributions. What follows are plausible contributors, not measured ones.

- **Part of the loss was never fat.** Fernando's review found fat-free mass fell as well as fat; if part of that is water, glycogen and gut contents, it would likely refill once daytime eating resumes.
- **The eating pattern changes back.** The modest drop in reported intake happened while meals were compressed into the night; once daytime meals return, that pattern ends.
- **Celebration meals follow immediately.** Eid al-Fitr is a festival of food and family. We could not find a study that quantified intake during Eid specifically, so we will not put a number on it; what is well documented is that people eat more with family and friends than alone, which is covered in the article on [why you eat more with friends](/blog/eating-with-others-and-overeating).

The conclusion Sadeghirad and colleagues drew is the fair one: Ramadan can be an opportunity to lose weight, but lasting change needs structured, consistent habits that continue after the month ends.

## Tracking during and after the month, if you choose to

This section is practical and carries no new research claims. It is for people who already track and want to keep doing so around Ramadan; it is not advice on whether or how to fast. If you have diabetes, are pregnant, take glucose-lowering medication or have a history of disordered eating, the question of fasting belongs with your clinician and religious guidance, and the [who should not fast](/blog/who-should-not-fast) article covers the medical side of that.

**Log the night as one day.** Suhoor and iftar fall on different calendar dates for many apps and diaries. Decide which "day" they belong to and stick with it, so a week of data compares like with like.

**Weigh at the same point in the cycle.** Weighing right after iftar and right before suhoor can differ substantially because of food and fluid. Pick one moment — for example, after waking from the main sleep — and use a weekly average rather than any single reading.

**Expect the rebound and plan for the two weeks after.** Based on the regain timeline above, a rise in the first two to five weeks after Ramadan is the expected pattern, not a sign that something went wrong. Continue your usual tracking routine after Ramadan to see how your own trend changes; if you use an [eating window](/blog/eating-window-and-weight-loss) outside Ramadan, those weeks are when you return to it.

**Check protein across iftar and suhoor.** The pooled data show protein intake dips slightly during Ramadan. For people who care about keeping lean mass, an easy check is whether iftar and suhoor together still reach your usual protein target.

## FAQ

### How much weight do people usually lose during Ramadan?

Pooled studies put the average at about 1 to 1.3 kg by the end of the month, with larger losses in people who start with a higher BMI. Findings on whether longer fasting days mean more loss differ between reviews.

### Why do I gain weight after Ramadan?

The loss is small and includes lean mass as well as fat, and the eating pattern that went with it ends when the month ends. Studies that followed people up show weight returning toward pre-Ramadan levels within two to five weeks; which factors drive that most is not established.

### Do people eat fewer calories during Ramadan?

On average yes, but only slightly: about 142 kcal a day less across 80 studies with energy data, with a wide range between individuals and food cultures.

### Does Ramadan fasting reduce sleep?

Yes, by about an hour a night on average in pooled studies, from roughly 7.2 to 6.4 hours.

## Sources

- [Sadeghirad B, Motaghipisheh S, Kolahdooz F, Zahedi MJ, Haghdoost AA. Islamic fasting and weight loss: a systematic review and meta-analysis. Public Health Nutrition. 2014;17(2):396-406.](https://pubmed.ncbi.nlm.nih.gov/23182306/)
- [Fernando HA, Zibellini J, Harris RA, Seimon RV, Sainsbury A. Effect of Ramadan Fasting on Weight and Body Composition in Healthy Non-Athlete Adults: A Systematic Review and Meta-Analysis. Nutrients. 2019;11(2):478.](https://pubmed.ncbi.nlm.nih.gov/30813495/)
- [Jahrami HA, Alsibai J, Clark CCT, Faris MAE. A systematic review, meta-analysis, and meta-regression of the impact of diurnal intermittent fasting during Ramadan on body weight in healthy subjects aged 16 years and above. European Journal of Nutrition. 2020;59(6):2291-2316.](https://pubmed.ncbi.nlm.nih.gov/32157368/)
- [Abdelrahim DN, El Herrag SE, Khaled MB, et al. Changes in energy and macronutrient intakes during Ramadan fasting: a systematic review, meta-analysis, and meta-regression. Nutrition Reviews. 2024;82(11):1482-1513.](https://pubmed.ncbi.nlm.nih.gov/37986623/)
- [Faris MAE, Jahrami HA, Alhayki FA, et al. Effect of diurnal fasting on sleep during Ramadan: a systematic review and meta-analysis. Sleep and Breathing. 2020;24(2):771-782.](https://pubmed.ncbi.nlm.nih.gov/31832984/)

Source: BurnWeek — "Ramadan fasting and weight: what the studies show", https://burnweek.fit/blog/ramadan-fasting-and-weight/. Licensed CC BY 4.0: free to quote or reuse with a link to this page.