{"id":94488,"date":"2026-10-14T11:05:32","date_gmt":"2026-10-14T11:05:32","guid":{"rendered":"https:\/\/betterme.world\/articles\/?p=94488"},"modified":"2026-10-14T11:05:32","modified_gmt":"2026-10-14T11:05:32","slug":"is-a-13-hour-fast-effective","status":"publish","type":"post","link":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/","title":{"rendered":"Is a 13-hour fast effective?"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_75 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#Key_takeaways\" >Key takeaways<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#What_do_studies_tell_us_about_fasting_duration\" >What do studies tell us about fasting duration?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#How_does_a_13-hour_fast_work\" >How does a 13-hour fast work?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#What_happens_after_13_hours_of_fasting\" >What happens after 13 hours of fasting?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#What_does_the_evidence_say_about_weight_loss\" >What does the evidence say about weight loss?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#What_can_you_eat_and_drink_during_a_13-hour_fast\" >What can you eat and drink during a 13-hour fast?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#When_should_you_start_and_end_a_13-hour_fast\" >When should you start and end a 13-hour fast?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#How_often_should_you_follow_a_13-hour_fast\" >How often should you follow a 13-hour fast?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#FAQs\" >FAQs<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#Does_a_medical_fast_follow_these_drink_rules\" >Does a medical fast follow these drink rules?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#Do_you_need_to_make_up_a_missed_fasting_day\" >Do you need to make up a missed fasting day?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#Should_you_change_medication_timing_to_fit_a_fast\" >Should you change medication timing to fit a fast?<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#The_bottom_line\" >The bottom line<\/a><\/li><\/ul><\/nav><\/div>\n<p><i><span style=\"font-weight: 400;\">Is a 13-hour fast effective? Direct evidence for that exact schedule is limited. It leaves an 11-hour eating window, which can organize meal times, but studies of longer fasting schedules cannot establish the same results for 13 hours. Food intake, individual circumstances, and the outcome being measured all matter.<\/span><\/i><\/p>\n<p><span data-sheets-root=\"1\"><a href=\"https:\/\/quiz.betterme.world\/first-page-generated-gender?flow=2273&amp;utm_source=Blog&amp;utm_medium=Blog&amp;utm_campaign=is_a_13_hour_fast_effective\" target=\"_blank\"><video autoplay=\"autoplay\" loop=\"loop\" muted=\"muted\" playsinline=\"playsinline\" width=\"777\"><source src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2021\/02\/ezgif.com-gif-to-mp4.mp4\" type=\"video\/mp4\" \/><\/video><\/a><\/span><\/p>\n<p><span style=\"font-weight: 400;\">For context on different schedules, see our <\/span><a href=\"https:\/\/betterme.world\/articles\/fasting-benefits-by-hour\/\"><span style=\"font-weight: 400;\">guide to fasting durations<\/span><\/a><span style=\"font-weight: 400;\">. This article explains the 13-hour schedule and the limits of research on its effects.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If you have diabetes, take glucose-lowering medication, are pregnant, or have a history of disordered eating, consult your doctor before trying fasting. Stop and seek advice if fasting makes you dizzy, unusually tired, or preoccupied with food.<\/span><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"Key_takeaways\"><\/span><b>Key takeaways<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A 13-hour fast leaves an 11-hour eating window within a 24-hour day.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The small trial comparing 12-, 14-, and 16-hour fasts did not test a 13-hour schedule (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The older-adult pilot study used an eight-hour eating window, equivalent to about 16 hours of fasting (<\/span><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41766355\/\"><span style=\"font-weight: 400;\">2<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The cited research does not establish a universal physiological threshold at hour 13 (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10111287\/\"><span style=\"font-weight: 400;\">3<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The 12-month trial compared an eight-hour eating window without calorie counting with prescribed calorie restriction; the diets were not calorie-matched (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10609268\/\"><span style=\"font-weight: 400;\">4<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">General time-restricted-eating findings cannot establish the effect of a specific 13-hour schedule (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10865403\/\"><span style=\"font-weight: 400;\">5<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The clock times and drink table in this article describe a schedule; medical fasting requires separate clinical instructions.<\/span><\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2025\/07\/walking-1.png\" \/><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"What_do_studies_tell_us_about_fasting_duration\"><\/span><b>What do studies tell us about fasting duration?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The cited studies do not establish one fasting duration for everyone. Time-restricted eating means eating within a consistent daily window; protocols and study populations vary (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10111287\/\"><span style=\"font-weight: 400;\">3<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">One small trial assigned 41 metabolically healthy, untrained adults to 12-hour, 14-hour, or 16-hour fasting schedules, or a control group, for eight weeks (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Only the 16-hour group showed significant body- and fat-mass changes in that trial. No group followed a 13-hour fast, and the small study cannot establish a universal ranking of schedules (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A separate nine-month pilot study in 90 adults aged 60 or older with overweight or obesity tested an eight-hour eating window, equivalent to roughly 16 hours of fasting. It does not provide evidence for an eight- to 13-hour fasting recommendation (<\/span><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41766355\/\"><span style=\"font-weight: 400;\">2<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">These differences in participants and schedules matter when applying research to a daily routine. The choice also needs to account for medical advice, meals, work, and sleep.<\/span><\/p>\n<p><em><strong>Read more:<\/strong> <a href=\"https:\/\/betterme.world\/articles\/72-hour-water-fast\/\">72-Hour Water Fast: What No One Tells You About<\/a><\/em><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"How_does_a_13-hour_fast_work\"><\/span><b>How does a 13-hour fast work?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">A 13-hour fast leaves 11 hours for eating in a 24-hour day. An overnight example is finishing food at 7:00 pm and having breakfast at 8:00 am.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A defined eating window changes when you plan meals and snacks. For example, an overnight schedule can mean:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Setting an evening time to finish eating.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Planning breakfast around the next morning\u2019s commitments.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Checking whether regular meals still fit the available window.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Our <\/span><a href=\"https:\/\/betterme.world\/articles\/12-hour-fasting-benefits\/\"><span style=\"font-weight: 400;\">12-hour fasting guide<\/span><\/a><span style=\"font-weight: 400;\"> explains a neighboring schedule. A shorter or longer window is a scheduling choice that also needs to fit your nutritional and medical circumstances.<\/span><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2025\/07\/senior-man.png\" \/><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"What_happens_after_13_hours_of_fasting\"><\/span><b>What happens after 13 hours of fasting?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The cited evidence does not establish a universal physiological event at hour 13. Responses to fasting vary, and research on time-restricted eating uses different windows, meal timing, and participant groups (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10111287\/\"><span style=\"font-weight: 400;\">3<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A precise clock time cannot establish that digestion is complete, that someone is in ketosis, or that a particular cellular process has reached a meaningful threshold. Those claims need direct measurements and evidence for the specific context.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Treat claims about a fixed hour for a body \u201creset\u201d cautiously. The studies discussed here do not define such a threshold (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10111287\/\"><span style=\"font-weight: 400;\">3<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">For additional scheduling examples, see our <\/span><a href=\"https:\/\/betterme.world\/articles\/13-hour-fast\/\"><span style=\"font-weight: 400;\">13-hour fasting schedule guide<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"What_does_the_evidence_say_about_weight_loss\"><\/span><b>What does the evidence say about weight loss?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The cited research does not establish a specific weight-loss effect from fasting for exactly 13 hours. A systematic review of time-restricted eating discusses the roles of energy intake and meal timing across varied protocols, so its pooled findings cannot be assigned directly to this schedule (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10865403\/\"><span style=\"font-weight: 400;\">5<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Weight change depends on more than the duration of the eating window. A schedule can change meal timing without necessarily reducing overall food intake.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In a 12-month trial involving 90 adults with obesity, an eight-hour eating window without calorie counting was compared with prescribed daily calorie restriction and a control group. The two dietary intervention groups had similar observed weight loss, but their calorie intake was not experimentally matched. This finding does not prove that the approaches are equivalent or establish an effect for a 13-hour fast (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10609268\/\"><span style=\"font-weight: 400;\">4<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The table distinguishes the schedule calculation from the limits of the evidence:<\/span><\/p>\n\t\t\t\t\t\t<div class=\"wpsm-comptable-wrap\">\n\t\t\t\t<table id=\"wpsm-table-1682\" class=\"wpsm-comptable \">\n\t\t\t\t\t\t\t\t\t<thead class=\"wpsm-thead wpsm-thead-default\">\n\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>Feature<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>13-hour fast<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>16-hour fast<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t<\/thead>\n\t\t\t\t\t<tbody class=\"wpsm-tbody\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tEating window\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t11 hours\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t8 hours\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tSample overnight hours\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t7:00 pm to 8:00 am\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t7:00 pm to 11:00 am\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tFood intake\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo calorie target implied\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo calorie target implied\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tEvidence discussed here\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo direct 13-hour trial cited\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tTested in several cited protocols (1, 2, 4)\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tIndividual suitability\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tRequires individual assessment\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tRequires individual assessment\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t<\/tbody>\n\t\t\t\t<\/table>\n\t\t\t<\/div>\n\t\t\n<p><span style=\"font-weight: 400;\">The sample times illustrate the arithmetic only. They are not prescriptions or predictions of body changes.<\/span><\/p>\n<p><strong>BetterMe can help you add more structure to your daily wellness routine with workouts, meal planning tools, and habit-building features. <a href=\"https:\/\/quiz.betterme.world\/first-page-generated-gender?flow=2273&amp;utm_source=Blog&amp;utm_medium=Blog&amp;utm_campaign=is_a_13_hour_fast_effective\">Explore the app<\/a> and take a practical step toward a routine that feels more manageable for you.<\/strong><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2025\/11\/image-6.png\" \/><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"What_can_you_eat_and_drink_during_a_13-hour_fast\"><\/span><b>What can you eat and drink during a 13-hour fast?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">For a calorie-free fasting window, water and unsweetened drinks are practical options. During eating hours, plan ordinary meals that provide enough food for your needs.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Examples of drinks without added calories include:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Water (still or sparkling)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Black coffee<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Plain tea<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Drinks and foods that contain calories belong within the eating window when following this definition:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Juice or soda<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Milk or creamers<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Protein shakes<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Sweetened coffee drinks<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Alcohol<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Snacks<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Milk, cream, sugar, and other additions contribute calories.<\/span><\/p>\n<p><em><strong>Read more:<\/strong> <a href=\"https:\/\/betterme.world\/articles\/long-term-effects-of-intermittent-fasting\/\">Long-Term Effects of Intermittent Fasting<\/a><\/em><\/p>\n<p><span style=\"font-weight: 400;\">Food composition and energy density can influence appetite and intake, with substantial variation between people (<\/span><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/37661746\/\"><span style=\"font-weight: 400;\">6<\/span><\/a><span style=\"font-weight: 400;\">). Practical meal components include:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Protein:<\/b><span style=\"font-weight: 400;\"> eggs, yogurt, beans, fish, lentils, tofu, or chicken.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Fiber:<\/b><span style=\"font-weight: 400;\"> vegetables, fruit, whole grains, and legumes.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Other foods you enjoy and can prepare regularly.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Drink options during a calorie-free fasting window:<\/span><\/p>\n\t\t\t\t\t\t<div class=\"wpsm-comptable-wrap\">\n\t\t\t\t<table id=\"wpsm-table-1683\" class=\"wpsm-comptable \">\n\t\t\t\t\t\t\t\t\t<thead class=\"wpsm-thead wpsm-thead-default\">\n\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>Drink<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>During fasting hours<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<th>Why<\/th>\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t<\/thead>\n\t\t\t\t\t<tbody class=\"wpsm-tbody\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tWater\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tYes\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo calories\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tBlack coffee\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tYes\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tVery few calories when plain\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tPlain tea\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tYes\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tVery few calories when unsweetened\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tJuice\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tContains sugar and calories\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<tr>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tLatte or sweet coffee\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tNo\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<td>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tMilk and sugar add calories\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/td>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/tr>\n\t\t\t\t\t\t\t\t\t\t<\/tbody>\n\t\t\t\t<\/table>\n\t\t\t<\/div>\n\t\t\n<p><span style=\"font-weight: 400;\">Plan the meals as well as the clock times. A schedule alone does not tell you whether your food intake meets your needs.<\/span><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2025\/11\/The-Chicken-And-Broccoli-Diet_-Why-This-Isnt-The-Weight-Loss-Solution-Youve-Been-Looking-For.png\" \/><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"When_should_you_start_and_end_a_13-hour_fast\"><\/span><b>When should you start and end a 13-hour fast?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Choose start and end times by counting 13 hours between the last calories one day and the first the next. The examples below show overnight windows; none is a clinically established preference for everyone.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Here are a few practical schedules to consider:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">One overnight example runs from 7:00 pm to 8:00 am.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Meal timing is a separate question from fasting duration. The studies cited here vary in their timing rules, so they cannot validate each of these sample clock times (<\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10111287\/\"><span style=\"font-weight: 400;\">3<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Check the schedule against your medication instructions, work hours, and regular meals before making a change.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Choosing your window comes down to your lifestyle:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">An evening cutoff after dinner can leave space for a shared meal.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">To keep an early breakfast, count backward 13 hours for the evening cutoff.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Check how that timing fits work and other commitments before adopting it.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Choose timing that leaves room for adequate meals and your usual commitments. If the schedule interferes with eating enough, reconsider it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can keep regular meal times without setting a fasting target.<\/span><\/p>\n<h2 style=\"text-align: center;\"><span class=\"ez-toc-section\" id=\"How_often_should_you_follow_a_13-hour_fast\"><\/span><b>How often should you follow a 13-hour fast?<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">The cited evidence does not establish a recommended weekly frequency for exactly 13 hours. The trials described here used repeated daily eating windows within specific research protocols (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41766355\/\"><span style=\"font-weight: 400;\">2<\/span><\/a><span style=\"font-weight: 400;\">, <\/span><a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC10609268\/\"><span style=\"font-weight: 400;\">4<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A study schedule is not an individual prescription. Discuss frequency with a qualified healthcare professional if you need guidance for your circumstances.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">There is no requirement to extend the fasting period or add more days. Regular meals without a fasting schedule are also an option.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A useful practical check is whether the schedule allows adequate meals and fits daily responsibilities. Hunger, mood, and energy alone cannot confirm a physiological benefit.<\/span><\/p>\n<p><strong>BetterMe: Health Coaching app can help you build a more structured approach to your wellness routine with meal plans, workouts, and habit-tracking tools. <a href=\"https:\/\/quiz.betterme.world\/first-page-generated-gender?flow=2273&amp;utm_source=Blog&amp;utm_medium=Blog&amp;utm_campaign=is_a_13_hour_fast_effective\">Start using the app<\/a> to explore options that may support your personal fitness and nutrition goals.<\/strong><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2024\/06\/Treadmill-Men-Banner-2.png\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"FAQs\"><\/span><b>FAQs<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2><ul><li><h3><span class=\"ez-toc-section\" id=\"Does_a_medical_fast_follow_these_drink_rules\"><\/span><strong>Does a medical fast follow these drink rules?<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3><\/li><\/ul><p><span style=\"font-weight: 400;\">No. Instructions before blood tests, anesthesia, or other procedures can differ from a self-selected eating schedule. Follow the clinical team\u2019s instructions about food, drinks, and medication.<\/span><\/p>\n<ul><li><h3><span class=\"ez-toc-section\" id=\"Do_you_need_to_make_up_a_missed_fasting_day\"><\/span><strong>Do you need to make up a missed fasting day?<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3><\/li><\/ul><p><span style=\"font-weight: 400;\">The cited studies do not establish a need to compensate for a missed day with a longer fast. Keep regular meals and avoid extending a fast just to balance a weekly total.<\/span><\/p>\n<ul><li><h3><span class=\"ez-toc-section\" id=\"Should_you_change_medication_timing_to_fit_a_fast\"><\/span><strong>Should you change medication timing to fit a fast?<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3><\/li><\/ul><p><span style=\"font-weight: 400;\">Ask your prescriber or pharmacist before changing medication timing. Some medicines must be taken with food, and the eating schedule should follow those instructions.<\/span><\/p>\n\n<p><span data-sheets-root=\"1\"><a href=\"https:\/\/quiz.betterme.world\/first-page-generated-gender?flow=2273&amp;utm_source=Blog&amp;utm_medium=Blog&amp;utm_campaign=is_a_13_hour_fast_effective\" target=\"_blank\"><video autoplay=\"autoplay\" loop=\"loop\" muted=\"muted\" playsinline=\"playsinline\" width=\"777\"><source src=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2023\/10\/ezgif.com-gif-to-mp4-12.mp4\" type=\"video\/mp4\" \/><\/video><\/a><\/span><\/p>\n<h2 style=\"text-align: left;\"><span class=\"ez-toc-section\" id=\"The_bottom_line\"><\/span><b>The bottom line<\/b><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">A 13-hour fast is an 11-hour eating window, and direct evidence for that exact schedule remains limited. If you are considering it, first check whether your meals and medication instructions fit. Use research on longer windows with care, and avoid treating a clock time as a promise of weight loss or a body reset.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Is a 13-hour fast effective? Direct evidence for that exact schedule is limited. It leaves an 11-hour eating window, which can organize meal times, but studies of longer fasting schedules cannot establish the same results for 13 hours. Food intake, individual circumstances, and the outcome being measured all matter. For context on different schedules, see [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":94490,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[150],"tags":[],"coauthors":[45],"class_list":["post-94488","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fasting-diet"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.8 (Yoast SEO v27.8) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Is a 13-hour fast effective? Evidence and meal timing<\/title>\n<meta name=\"description\" content=\"\u2605 IS A 13 HOUR FAST EFFECTIVE \u27a4? Review the evidence, see eating windows, and understand the limits of research before deciding whether to change meal timing.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Is a 13-hour fast effective?\" \/>\n<meta property=\"og:description\" content=\"\u2605 IS A 13 HOUR FAST EFFECTIVE \u27a4? Review the evidence, see eating windows, and understand the limits of research before deciding whether to change meal timing.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/\" \/>\n<meta property=\"og:site_name\" content=\"BetterMe Blog\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/betterme.health.coaching\" \/>\n<meta property=\"article:author\" content=\"#\" \/>\n<meta property=\"og:image\" content=\"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2026\/10\/1569-is-a-13-hour-fast-effective-1.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"1536\" \/>\n\t<meta property=\"og:image:height\" content=\"1024\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"author\" content=\"BetterMe\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@betterme\" \/>\n<meta name=\"twitter:site\" content=\"@betterme\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"BetterMe\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"8 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/\"},\"author\":{\"name\":\"BetterMe\",\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/#\\\/schema\\\/person\\\/41ef0d9349957b3810a70e9bd1032249\"},\"headline\":\"Is a 13-hour fast effective?\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/\"},\"wordCount\":1411,\"publisher\":{\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/cdn.betterme.world\\\/articles\\\/wp-content\\\/uploads\\\/2026\\\/10\\\/1569-is-a-13-hour-fast-effective-1.webp\",\"articleSection\":[\"Fasting\"],\"inLanguage\":\"en-US\",\"articleBody\":\"<i><span style=\\\"font-weight: 400;\\\">Is a 13-hour fast effective? Direct evidence for that exact schedule is limited. It leaves an 11-hour eating window, which can organize meal times, but studies of longer fasting schedules cannot establish the same results for 13 hours. Food intake, individual circumstances, and the outcome being measured all matter.<\\\/span><\\\/i>\\r\\n\\r\\n<span data-sheets-root=\\\"1\\\"><\\\/span>\\r\\n\\r\\n<span style=\\\"font-weight: 400;\\\">For context on different schedules, see our <\\\/span><a href=\\\"https:\\\/\\\/betterme.world\\\/articles\\\/fasting-benefits-by-hour\\\/\\\"><span style=\\\"font-weight: 400;\\\">guide to fasting durations<\\\/span><\\\/a><span style=\\\"font-weight: 400;\\\">. This article explains the 13-hour schedule and the limits of research on its effects.<\\\/span>\\r\\n\\r\\n<span style=\\\"font-weight: 400;\\\">If you have diabetes, take glucose-lowering medication, are pregnant, or have a history of disordered eating, consult your doctor before trying fasting. Stop and seek advice if fasting makes you dizzy, unusually tired, or preoccupied with food.<\\\/span>\\r\\n<h2 style=\\\"text-align: center;\\\"><b>Key takeaways<\\\/b><\\\/h2>\\r\\n<ul>\\r\\n \\t<li style=\\\"font-weight: 400;\\\" aria-level=\\\"1\\\"><span style=\\\"font-weight: 400;\\\">A 13-hour fast leaves an 11-hour eating window within a 24-hour day.<\\\/span><\\\/li>\\r\\n \\t<li style=\\\"font-weight: 400;\\\" aria-level=\\\"1\\\"><span style=\\\"font-weight: 400;\\\">The small trial comparing 12-, 14-, and 16-hour fasts did not test a 13-hour schedule (<\\\/span><a href=\\\"https:\\\/\\\/link.springer.com\\\/article\\\/10.1186\\\/s12967-024-05849-6\\\"><span style=\\\"font-weight: 400;\\\">1<\\\/span><\\\/a><span style=\\\"font-weight: 400;\\\">).<\\\/span><\\\/li>\\r\\n \\t<li style=\\\"font-weight: 400;\\\" aria-level=\\\"1\\\"><span style=\\\"font-weight: 400;\\\">The older-adult pilot study used an eight-hour eating window, equivalent to about 16 hours of fasting (<\\\/span><a href=\\\"https:\\\/\\\/pubmed.ncbi.nlm.nih.gov\\\/41766355\\\/\\\"><span style=\\\"font-weight: 400;\\\">2<\\\/span><\\\/a><span style=\\\"font-weight: 400;\\\">).<\\\/span><\\\/li>\\r\\n \\t<li style=\\\"font-weight: 400;\\\" aria-level=\\\"1\\\"><span style=\\\"font- ...\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/\",\"url\":\"https:\\\/\\\/betterme.world\\\/articles\\\/is-a-13-hour-fast-effective\\\/\",\"name\":\"Is a 13-hour fast effective? 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Evidence and meal timing","description":"\u2605 IS A 13 HOUR FAST EFFECTIVE \u27a4? Review the evidence, see eating windows, and understand the limits of research before deciding whether to change meal timing.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/","og_locale":"en_US","og_type":"article","og_title":"Is a 13-hour fast effective?","og_description":"\u2605 IS A 13 HOUR FAST EFFECTIVE \u27a4? Review the evidence, see eating windows, and understand the limits of research before deciding whether to change meal timing.","og_url":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/","og_site_name":"BetterMe Blog","article_publisher":"https:\/\/www.facebook.com\/betterme.health.coaching","article_author":"#","og_image":[{"width":1536,"height":1024,"url":"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2026\/10\/1569-is-a-13-hour-fast-effective-1.webp","type":"image\/webp"}],"author":"BetterMe","twitter_card":"summary_large_image","twitter_creator":"@betterme","twitter_site":"@betterme","twitter_misc":{"Written by":"BetterMe","Est. reading time":"8 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#article","isPartOf":{"@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/"},"author":{"name":"BetterMe","@id":"https:\/\/betterme.world\/articles\/#\/schema\/person\/41ef0d9349957b3810a70e9bd1032249"},"headline":"Is a 13-hour fast effective?","mainEntityOfPage":{"@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/"},"wordCount":1411,"publisher":{"@id":"https:\/\/betterme.world\/articles\/#organization"},"image":{"@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#primaryimage"},"thumbnailUrl":"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2026\/10\/1569-is-a-13-hour-fast-effective-1.webp","articleSection":["Fasting"],"inLanguage":"en-US","articleBody":"<i><span style=\"font-weight: 400;\">Is a 13-hour fast effective? Direct evidence for that exact schedule is limited. It leaves an 11-hour eating window, which can organize meal times, but studies of longer fasting schedules cannot establish the same results for 13 hours. Food intake, individual circumstances, and the outcome being measured all matter.<\/span><\/i>\r\n\r\n<span data-sheets-root=\"1\"><\/span>\r\n\r\n<span style=\"font-weight: 400;\">For context on different schedules, see our <\/span><a href=\"https:\/\/betterme.world\/articles\/fasting-benefits-by-hour\/\"><span style=\"font-weight: 400;\">guide to fasting durations<\/span><\/a><span style=\"font-weight: 400;\">. This article explains the 13-hour schedule and the limits of research on its effects.<\/span>\r\n\r\n<span style=\"font-weight: 400;\">If you have diabetes, take glucose-lowering medication, are pregnant, or have a history of disordered eating, consult your doctor before trying fasting. Stop and seek advice if fasting makes you dizzy, unusually tired, or preoccupied with food.<\/span>\r\n<h2 style=\"text-align: center;\"><b>Key takeaways<\/b><\/h2>\r\n<ul>\r\n \t<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">A 13-hour fast leaves an 11-hour eating window within a 24-hour day.<\/span><\/li>\r\n \t<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The small trial comparing 12-, 14-, and 16-hour fasts did not test a 13-hour schedule (<\/span><a href=\"https:\/\/link.springer.com\/article\/10.1186\/s12967-024-05849-6\"><span style=\"font-weight: 400;\">1<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\r\n \t<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The older-adult pilot study used an eight-hour eating window, equivalent to about 16 hours of fasting (<\/span><a href=\"https:\/\/pubmed.ncbi.nlm.nih.gov\/41766355\/\"><span style=\"font-weight: 400;\">2<\/span><\/a><span style=\"font-weight: 400;\">).<\/span><\/li>\r\n \t<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font- ..."},{"@type":"WebPage","@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/","url":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/","name":"Is a 13-hour fast effective? Evidence and meal timing","isPartOf":{"@id":"https:\/\/betterme.world\/articles\/#website"},"primaryImageOfPage":{"@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#primaryimage"},"image":{"@id":"https:\/\/betterme.world\/articles\/is-a-13-hour-fast-effective\/#primaryimage"},"thumbnailUrl":"https:\/\/cdn.betterme.world\/articles\/wp-content\/uploads\/2026\/10\/1569-is-a-13-hour-fast-effective-1.webp","description":"\u2605 IS A 13 HOUR FAST EFFECTIVE \u27a4? 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