Randomised controlled trialindependent cross-checkabstract only checked★ key study I-FAST-03 in-depth review
Time-restricted eating plus calorie restriction
Calorie Restriction with or without Time-Restricted Eating in Weight Loss.
Overview
Liu D et al.. N Engl J Med 2022 · PMID 35443107 · DOI 10.1056/NEJMoa2114833
Adding an 8-hour eating window to calorie restriction did not significantly improve weight loss.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Time-restricted eating plus calorie restriction vs calorie restriction alone
- How was the study done?
RCT, 12 months
- How many people, animals or samples were studied?
139; Adults with obesity
- What was actually found?
No significant added benefit.
- How large was the observed effect?
-1.8 kg (n.s.)
- What do the results mean in everyday life?
Calorie reduction is what matters.
- What are the study's limitations?
Single country
- What does it say about Elawady's specific claim?
- Do the results apply to Germany and Europe?
Chinese population; physiology transferable.
- What can explicitly not be concluded from this study?
Effects without calorie restriction.
Scientific in-depth review
1. Full reference
- Authors
- Liu D et al.
- Journal
- N Engl J Med
- Year
- 2022
- Identifier
- PMID 35443107 DOI 10.1056/NEJMoa2114833
- Verification
- verified – PubMed efetch 2026-10-25 (this agent)
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Time-restricted eating plus calorie restriction vs calorie restriction alone
3. Study design and population
- Study design
- Randomised controlled trial – RCT, 12 months
- Population
Adults with obesity
- Country
China
- Period
12 months
- Sample size
139
- Inclusion and exclusion criteria
As described in the abstract; details not available in abstract.
4. Methods and endpoints
- Exposure / intervention
8:00-16:00 eating window + calorie restriction
- Comparator
Calorie restriction alone
- Endpoints
Weight change; fat, metabolic markers
- Statistical methods
Intention to treat
5. Actual results
- Results
Weight -8.0 kg (-9.6 to -6.4) vs -6.3 kg (-7.8 to -4.7); difference -1.8 kg (-4.0 to 0.4; P=0.11); secondary outcomes consistent; no difference in adverse events.
- Absolute risks
not reported
- Authors' conclusion
TRE was not more beneficial than daily calorie restriction for weight, fat or metabolic risk factors.
6. Strengths
- 12-month RCT
- 85% completion
7. Weaknesses
- Single country
8. Risk of bias
- Orienting tool
- RoB 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Adequate design.
9. Assessment of the statistical interpretation
Non-significant difference.
10. Relevance to the specific claim
11. Independent contrary findings
12. Transferability to Germany and Europe
Chinese population; physiology transferable.
13. Overall methodological judgement
High-quality evidence of no added benefit.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
None beyond those stated.
15. Linked fact checks
- Fasting gives the liver and gut the chance to repair themselves and expel toxins; intermittent fasting is the only treatment for fatty liver and treats joint pain, autoimmune and allergy-like symptoms. – Studies contradicting or limiting the claim
- Health equals the ability to avoid toxic inputs: zero inputs means infinite health; complete abstinence from all inputs (fasting) keeps the body in a state that does not become ill, and not eating for three or four days makes the body strong. – Studies contradicting or limiting the claim
- Long daily intermittent fasting with one meal a day as the default eating pattern (and sometimes eating once every two days) is the healthy way to eat. – Studies supporting the claim
- Calories are not a relevant concept ('there is no such thing as calories'); his system is based on high calorie intake, and people lose weight while eating sugar, juices, fats, potatoes and rice, because with 'zero insulin' no fat is formed (the passage continues: 'even if you drink oil, even if you swallow bags of sugar'). Elsewhere he says he drinks 6 litres of sugar-cane juice and eats baladi ghee, rice and potatoes every day. – Studies contradicting or limiting the claim