Claim: Eating food late at night causes weight gain

First requested: April 30, 2026 at 10:14 AM
64%

IsItCap Score

Truth Potential Meter

Moderately Credible

AI consensusWeak

Grader consensus is weak.
Range 50%–70% (spread Δ20).
The graders diverge. Treat the combined score as uncertain and read the sources carefully.
Read analysis summary

OpenAI Grade

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70%

Perplexity Grade

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Google Gemini Grade

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Analysis Summary

The claim that eating food late at night causes weight gain is mostly true, supported by studies indicating that late-night eating can disrupt metabolism and increase fat storage. Research from institutions like Northwestern and Harvard shows mechanisms linking late eating to weight gain through hormonal changes and altered energy expenditure. However, some experts argue that weight gain is primarily influenced by total calorie intake rather than timing, highlighting a need for more human studies to confirm these findings. This debate suggests that while late-night eating may contribute to weight gain, it is not the sole factor involved. The graders interpret the evidence differently, so the score range widens. OpenAI comes in highest (70%), while Gemini is lowest (50%). OpenAI expresses higher confidence than Gemini on this claim. Opposing sources claim that the relationship between late-night eating and weight gain is not well-established in humans, suggesting that weight gain is more about total calorie consumption than the timing of meals. They argue that the mouse studies, while revealing potential mechanisms, do not directly translate to human physiology. This uncertainty does not negate the evidence supporting the claim but indicates that more comprehensive human studies are necessary to fully understand the impact of late-night eating on weight gain.
Jump to source analysis

Source quality

Truth (from sources)7.00 / 10
Source reliability8.00 / 10
Source independence7.00 / 10

Claim checks

Fits established facts6.00 / 10
Logical consistency7.00 / 10
Expert consensus6.00 / 10
Related fact checks

Source Analysis

Mainstream Sources

Publication

news.feinberg.northwestern.edu

Title

Why Late-Night Eating Leads to Weight Gain, Diabetes

Summary

Northwestern Medicine study in Science shows mechanism linking late-night eating to weight gain via disrupted circadian rhythms in fat tissue, with mice gaining more weight when fed during inactive periods despite same calories.

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Publication

health.harvard.edu

Title

Harvard study: Curb late-night eating to stave off weight gain

Summary

2022 study found eating later increases hunger, reduces calorie burn, and promotes fat storage, leading to weight gain over time.

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Publication

endocrine.org

Title

People who eat a late dinner may gain weight

Summary

Small study in Journal of Clinical Endocrinology & Metabolism shows late dinner (10pm vs 6pm) raises blood sugar 18% higher and reduces fat burn by 10%, potentially leading to weight gain.

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Alternative Sources

Publication

webmd.com

Title

Diet Truth or Myth: Eating at Night Causes Weight Gain

Summary

Mouse studies show nighttime eating causes more weight gain, but human evidence lacking; weight gain primarily from total calories, not timing.

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Publication

uamshealth.com

Title

Does Eating Late at Night Make you Fat?

Summary

Calories at night do not metabolize differently or cause more weight gain than daytime calories.

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Analysis Breakdown

True/False Spectrum (7.0)Source Credibility (8.0)Bias Assessment (7.0)Contextual Integrity (6.0)Content Coherence (7.0)Expert Consensus (6.0)68%

How to read the breakdown

Weakest areas
Context6.0/10Consensus6.0/10
  • Truth: how well sources support the core claim.
  • Source reliability: whether the sources have a strong track record.
  • Independence: whether coverage looks one-sided or recycled.
  • Context: missing details (timeframe, definitions, scope) that change meaning.
  • Tip: if graders disagree, rely more on the summary + sources than the single number.

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Methodology