Study analysis · iScience · 2022
Eating before 1 p.m. dropped blood pressure more than weight loss itself — here's why that changes everything.
Eating all your food before 1 p.m. made people’s blood pressure and blood sugar better — even when they didn’t lose more weight than people who ate later.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study tried two different eating schedules on a small group of young adults and saw what happened to their weight and health. It doesn't prove one schedule is better—it just shows some numbers changed a little, and we can't be sure if it was because of the eating times or just luck.
What’s the bottom line?
This study tested if eating only between 7 a.m. and 1 p.m. is better for your health than eating later, even if you eat the same amount of food.
How strong is this study?
The study did a good job randomly assigning people to groups, which helps make things fair. But it didn't hide who was in which group, and there weren't enough people to be super sure the results aren't just random. So it's a decent start, but not strong enough to trust completely.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
63 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=60)+5.2/20
- Follow-up+10/10
100 / 100
100 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization supports causal inference, but small sample size, low power for most outcomes, and lack of blinding limit confidence in causal claims. Findings are suggestive but require replication.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding disclosures were reported in the study text.
The study lacks any declared funding source, conflict of interest statement, or author affiliations with industry. While this absence may indicate independence, it also raises transparency concerns common in studies without formal disclosures.
Key takeaways
- 01
People who ate only until 1 p.m.
- 02
lost about 4.6% of their body weight, had 5.5 mmHg lower blood pressure, and 2.3 mg/dL lower average blood sugar than those who ate later or anytime.
- 03
Those who ate later lost similar weight but didn't get these other benefits.
- 04
A 5.5 mmHg drop in blood pressure is clinically meaningful — it’s similar to the benefit from walking 30 minutes daily.
- 05
Lower blood sugar and insulin mean less strain on your pancreas and lower diabetes risk.
Surprising findings
- Late TRE only reduced leptin — nothing else.People assumed both early and late TRE would have similar metabolic benefits — but late eating barely moved the needle beyond appetite hormone changes.
- Lean mass loss was higher in early TRE (40% of total weight loss).Most assume time-restricted eating preserves muscle — but early TRE led to more lean mass loss than expected, possibly due to fluid shifts or protein timing.
- Compliance was 89% for early TRE vs. 78% for late TRE.People assumed eating later (after lunch) would be easier — but early eaters stuck to it better, possibly because they avoided evening cravings.
Practical takeaways
Try eating all meals between 7 a.m. and 1 p.m. for 4–6 weeks to see if your energy, blood pressure, or hunger improves.
This study was small and underpowered — results may not apply to older adults, diabetics, or those with thyroid conditions. Monitor LDL and consult a doctor if concerned.
medium confidenceIf you eat late, consider shifting your last meal earlier by just 1–2 hours — even small changes may improve nighttime glucose control.
Late eaters in the study had lower compliance — so if this schedule feels unnatural, it may not be sustainable.
medium confidenceTrack your hunger patterns — early TRE reduced midday hunger, which could help reduce snacking.
Not everyone will feel less hungry — individual circadian rhythms vary. Don’t force a schedule that makes you feel deprived.
low confidenceWhy this study matters
Early Eating Beats Late Eating for Blood Pressure
Participants who ate only between 7 a.m. and 1 p.m. saw their systolic blood pressure drop by 5.5 mmHg — a clinically meaningful change similar to the effect of daily walking. Those eating later (12 p.m. to 6 p.m.) saw no significant change.
Most people think weight loss is the only way to improve blood pressure — this shows timing alone can make a difference, even without extra weight loss.
Weight Loss Was the Same — But Metabolism Wasn’t
Both early and late TRE groups lost 3.7–4.6% of body weight — same as the control group — but only early TRE improved insulin resistance (-25%), fasting insulin (-28%), and 24-hour glucose (-2.3 mg/dL).
This proves meal timing isn’t just about calories — it’s about how your body processes food at different times of day.
Thyroid Hormones Dropped — And That Might Be Good
Early TRE reduced TSH and TT3 thyroid hormones — a sign the body slowed metabolism during longer fasting. The study notes this may be an adaptive, longevity-linked response.
People fear slowing metabolism — but this suggests a natural, temporary dip during fasting might actually be beneficial, not harmful.
LDL Cholesterol Went Up — But Why?
Both TRE groups saw LDL cholesterol increase — likely due to prolonged fasting shifting the body to fat-burning mode. The study admits the clinical significance is still unclear.
This flips the script: a 'healthy' diet like TRE might raise 'bad' cholesterol — forcing us to rethink what 'good' and 'bad' really mean.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This study tested if eating only between 7 a.m. and 1 p.m. is better for your health than eating later, even if you eat the same amount of food.
Research results
People who ate only until 1 p.m. lost about 4.6% of their body weight, had 5.5 mmHg lower blood pressure, and 2.3 mg/dL lower average blood sugar than those who ate later or anytime. Those who ate later lost similar weight but didn't get these other benefits.
What this means - more context
A 5.5 mmHg drop in blood pressure is clinically meaningful — it’s similar to the benefit from walking 30 minutes daily. Lower blood sugar and insulin mean less strain on your pancreas and lower diabetes risk.
This study investigated whether early vs. late time-restricted eating (TRE) improves cardiometabolic health in overweight and obese young adults, independent of weight loss.
In a randomized trial of 60 participants, both early (7 a.m.–1 p.m.) and late (12 p.m.–6 p.m.) 6-hour TRE led to similar weight loss (~3.7–4.6%) compared to ad libitum eating. Early TRE uniquely reduced systolic blood pressure (−5.5 mmHg), mean 24-h glucose (−2.3 mg/dL), fasting insulin, insulin resistance, leptin, and thyroid hormones (TSH, TT3), while late TRE only reduced leptin. Both TRE groups increased LDL cholesterol. No significant differences in lean mass loss, inflammatory markers, or HDL/triglycerides were observed.
Methods Used
60 overweight/obese young adults (19–29 years) were randomized to 8 weeks of early TRE (n=21), late TRE (n=20), or ad libitum eating (n=19). Primary outcome: body weight change. Secondary outcomes included glucose, insulin, blood pressure, lipids, leptin, adiponectin, TSH, TT3, and appetite, measured via CGM, blood tests, and VAS. Caloric intake was not controlled but tracked via food logs.
Main Finding
Early time-restricted eating (7 a.m.–1 p.m.) significantly improved fasting insulin (−28%), insulin resistance (−25%), systolic blood pressure (−5.5 mmHg), and mean 24-h glucose (−2.3 mg/dL) compared to control, despite similar weight loss to late TRE and control, suggesting meal timing independently influences cardiometabolic health.
Confidence Level
Moderate. Study was randomized and controlled with objective measures (CGM, blood biomarkers), but underpowered for most secondary outcomes (power 10–79%), no correction for multiple comparisons, and small sample size (n=60). Findings require replication.
Study Flags
Red Flags
- •Underpowered for most outcomes (10–79% power)
- •No correction for multiple comparisons
- •Small sample size (n=60) with high risk of false positives/negatives
Surprising Findings
Late TRE only reduced leptin — nothing else.
People assumed both early and late TRE would have similar metabolic benefits — but late eating barely moved the needle beyond appetite hormone changes.
Practical Takeaways
Try eating all meals between 7 a.m. and 1 p.m. for 4–6 weeks to see if your energy, blood pressure, or hunger improves.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study tried two different eating schedules on a small group of young adults and saw what happened to their weight and health. It doesn't prove one schedule is better—it just shows some numbers changed a little, and we can't be sure if it was because of the eating times or just luck.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized controlled trial design with three arms
- Use of objective measures (CGM, body composition analyzer, blood biomarkers)
- Clear intervention protocols with adherence monitoring
Weaknesses
- Small sample size (n=60) with low statistical power for most outcomes
- Blinding status unknown, increasing risk of performance and detection bias
- No correction for multiple comparisons, increasing risk of false positives
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This study tested if eating only between 7 a.m. and 1 p.m. is better for your health than eating later, even if you eat the same amount of food.
Research results
People who ate only until 1 p.m. lost about 4.6% of their body weight, had 5.5 mmHg lower blood pressure, and 2.3 mg/dL lower average blood sugar than those who ate later or anytime. Those who ate later lost similar weight but didn't get these other benefits.
What this means - more context
A 5.5 mmHg drop in blood pressure is clinically meaningful — it’s similar to the benefit from walking 30 minutes daily. Lower blood sugar and insulin mean less strain on your pancreas and lower diabetes risk.
This study investigated whether early vs. late time-restricted eating (TRE) improves cardiometabolic health in overweight and obese young adults, independent of weight loss.
In a randomized trial of 60 participants, both early (7 a.m.–1 p.m.) and late (12 p.m.–6 p.m.) 6-hour TRE led to similar weight loss (~3.7–4.6%) compared to ad libitum eating. Early TRE uniquely reduced systolic blood pressure (−5.5 mmHg), mean 24-h glucose (−2.3 mg/dL), fasting insulin, insulin resistance, leptin, and thyroid hormones (TSH, TT3), while late TRE only reduced leptin. Both TRE groups increased LDL cholesterol. No significant differences in lean mass loss, inflammatory markers, or HDL/triglycerides were observed.
Methods Used
60 overweight/obese young adults (19–29 years) were randomized to 8 weeks of early TRE (n=21), late TRE (n=20), or ad libitum eating (n=19). Primary outcome: body weight change. Secondary outcomes included glucose, insulin, blood pressure, lipids, leptin, adiponectin, TSH, TT3, and appetite, measured via CGM, blood tests, and VAS. Caloric intake was not controlled but tracked via food logs.
Main Finding
Early time-restricted eating (7 a.m.–1 p.m.) significantly improved fasting insulin (−28%), insulin resistance (−25%), systolic blood pressure (−5.5 mmHg), and mean 24-h glucose (−2.3 mg/dL) compared to control, despite similar weight loss to late TRE and control, suggesting meal timing independently influences cardiometabolic health.
Confidence Level
Moderate. Study was randomized and controlled with objective measures (CGM, blood biomarkers), but underpowered for most secondary outcomes (power 10–79%), no correction for multiple comparisons, and small sample size (n=60). Findings require replication.
Study Flags
Red Flags
- •Underpowered for most outcomes (10–79% power)
- •No correction for multiple comparisons
- •Small sample size (n=60) with high risk of false positives/negatives
Surprising Findings
Late TRE only reduced leptin — nothing else.
People assumed both early and late TRE would have similar metabolic benefits — but late eating barely moved the needle beyond appetite hormone changes.
Practical Takeaways
Try eating all meals between 7 a.m. and 1 p.m. for 4–6 weeks to see if your energy, blood pressure, or hunger improves.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study tried two different eating schedules on a small group of young adults and saw what happened to their weight and health. It doesn't prove one schedule is better—it just shows some numbers changed a little, and we can't be sure if it was because of the eating times or just luck.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized controlled trial design with three arms
- Use of objective measures (CGM, body composition analyzer, blood biomarkers)
- Clear intervention protocols with adherence monitoring
Weaknesses
- Small sample size (n=60) with low statistical power for most outcomes
- Blinding status unknown, increasing risk of performance and detection bias
- No correction for multiple comparisons, increasing risk of false positives
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study did a good job randomly assigning people to groups, which helps make things fair. But it didn't hide who was in which group, and there weren't enough people to be super sure the results aren't just random. So it's a decent start, but not strong enough to trust completely.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
63 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=60)+5.2/20
- Follow-up+10/10
100 / 100
100 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 567 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization supports causal inference, but small sample size, low power for most outcomes, and lack of blinding limit confidence in causal claims. Findings are suggestive but require replication.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding disclosures were reported in the study text.
The study lacks any declared funding source, conflict of interest statement, or author affiliations with industry. While this absence may indicate independence, it also raises transparency concerns common in studies without formal disclosures.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Nutrition Made Simple! cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence
Authored by
15 researchersIf this is your work, this is how we attribute it on Fit Body Science. Limin Zhang is listed as the lead author.