Study analysis · Journal of Gastroenterology · 2025
Trans fats make your liver fat and your belly fat disappear—here's why.
Eating trans fats turns on a liver gene that traps fat in your liver and steals it from your belly, even if you don’t eat more calories.
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 saw that when mice and human liver cells were fed trans fats, they made more of a protein called GPAM and stored more fat. But it didn't prove that trans fats caused the fat buildup — it just showed they often happened together.
What’s the bottom line?
Eating trans fats turns on a gene called GPAM in your liver, which tricks your body into storing fat in the liver instead of around your belly.
How strong is this study?
The scientists did a good job testing their idea in different ways — in cells, in mice, and in human tissue. But they didn't randomly assign who got what diet, so we can't be sure other things (like genetics or other foods) didn't cause the results. That makes the findings interesting but not totally trustworthy for making health rules.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
19 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample sizeno sample size reported
- Follow-upno follow-up reported
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
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 540 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. This study uses animal and in vitro models with no randomization or blinding reported, and includes observational human data without controlled intervention. Without randomization, confounding factors cannot be ruled out, so causation cannot be established.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding statements were disclosed in the provided text, and no industry affiliations or financial ties were identified among the authors.
The study lacks any declared funding sources or conflict of interest statement, which is a limitation for transparency. However, no evidence of industry influence, author employment by companies, or funder involvement in study design or analysis was found in the provided text.
Key takeaways
- 01
Mice on trans fats had 40% more liver fat and 30% less belly fat than mice on other fats; humans with severe liver fat had much higher GPAM levels.
- 02
Yes — this means trans fats may cause fatty liver disease while making it harder to lose belly fat, even if you don't eat more calories.
Surprising findings
- Trans fats reduced visceral adipose tissue (VAT) while increasing liver fat—opposite of what most high-fat diets do.Everyone assumes high-fat diets = more belly fat. This study shows trans fats uniquely reroute fat storage, making you 'skinny-fat' with a ticking time bomb in your liver.
- GPAM knockdown didn’t just reduce liver fat—it restored visceral fat in mice.Blocking one gene reversed both the liver damage AND brought back lost belly fat. This suggests fat wasn’t burned off—it was just misplaced.
Practical takeaways
Avoid any food with 'partially hydrogenated oils' on the label—even if it says '0g trans fat' (FDA allows up to 0.5g per serving).
This study used high-fat diets; real-world exposure is often lower, but cumulative effects over years may still be harmful.
high confidenceIf you have fatty liver, eliminate trans fats first—this study suggests they may be actively worsening your condition by redirecting fat into your liver.
GPAM knockdown was done via experimental nanodevices—not something you can do at home. Diet change is the only current option.
high confidenceWhy this study matters
The Fat Shift Mystery
Mice fed trans fats had 40% more liver fat and 30% less visceral fat than those on other fats. Human liver biopsies showed the same pattern: higher GPAM gene expression correlated with severe fatty liver and reduced belly fat.
This flips the script—most people think fat goes to the belly when you overeat, but trans fats trick your body into storing fat in your liver instead, which is far more dangerous.
GPAM: The Fat Redirector Gene
The study found GPAM is the key switch: when overexpressed, liver cells accumulated more triglycerides; when knocked down with siRNA, liver fat dropped and belly fat returned. This was replicated in both mice and human liver cells.
This isn’t just correlation—it’s causation. GPAM isn’t just a marker; it’s the mechanism that physically redirects fat storage away from fat tissue and into the liver.
ALT Levels Reveal Hidden Liver Damage
Trans-fat-fed mice and humans showed significantly higher serum alanine aminotransferase (ALT)—a marker of liver cell injury—compared to those on palmitic or oleic acid diets.
You might look fine on the scale, but your liver could be screaming for help. This shows trans fats damage your liver even without visible weight gain.
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
Eating trans fats turns on a gene called GPAM in your liver, which tricks your body into storing fat in the liver instead of around your belly.
Research results
Mice on trans fats had 40% more liver fat and 30% less belly fat than mice on other fats; humans with severe liver fat had much higher GPAM levels.
What this means - more context
Yes — this means trans fats may cause fatty liver disease while making it harder to lose belly fat, even if you don't eat more calories.
This study investigates how trans-fatty acid consumption drives hepatic fat accumulation and reduces visceral fat via GPAM upregulation in metabolic dysfunction-associated steatotic liver disease (MASLD).
Trans-fatty acids increased hepatic GPAM expression, leading to higher liver triglycerides and lower visceral adipose tissue in mice and humans, while GPAM knockdown reversed these effects. Human liver samples confirmed GPAM levels correlate with steatosis severity.
Methods Used
Mice were fed high-fat diets rich in palmitic acid, trans-fatty acids, or oleic acid; Hepa 1-6 cells were exposed to these fatty acids; GPAM was manipulated via overexpression and siRNA knockdown using a pH-sensitive nanodevice; human MASLD liver biopsies were analyzed for GPAM expression.
Main Finding
Trans-fatty acid consumption increased hepatic GPAM expression, which directly caused elevated liver triglycerides and reduced visceral adipose tissue; GPAM knockdown suppressed steatosis and restored visceral fat in mice.
Confidence Level
High — the study uses causal manipulations (siRNA knockdown, overexpression) in both mice and human cells, supported by correlative human tissue data, with consistent findings across models.
Study Flags
Red Flags
- •Human data limited to correlative biopsy analysis
- •No direct measurement of caloric intake control in humans
- •Nanodevice delivery method not fully characterized for long-term safety
Surprising Findings
Trans fats reduced visceral adipose tissue (VAT) while increasing liver fat—opposite of what most high-fat diets do.
Everyone assumes high-fat diets = more belly fat. This study shows trans fats uniquely reroute fat storage, making you 'skinny-fat' with a ticking time bomb in your liver.
Practical Takeaways
Avoid any food with 'partially hydrogenated oils' on the label—even if it says '0g trans fat' (FDA allows up to 0.5g per serving).
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 540 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study saw that when mice and human liver cells were fed trans fats, they made more of a protein called GPAM and stored more fat. But it didn't prove that trans fats caused the fat buildup — it just showed they often happened together.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Multi-model approach (in vivo mice, in vitro cells, human tissue) strengthens biological plausibility
- Use of genetic manipulation (siRNA, overexpression) to test mechanistic role of GPAM
- Clear and consistent findings across experimental systems
Weaknesses
- No randomization reported — cannot rule out confounding
- Blinding status unknown — risk of measurement bias
- No sample size justification or power calculation
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Eating trans fats turns on a gene called GPAM in your liver, which tricks your body into storing fat in the liver instead of around your belly.
Research results
Mice on trans fats had 40% more liver fat and 30% less belly fat than mice on other fats; humans with severe liver fat had much higher GPAM levels.
What this means - more context
Yes — this means trans fats may cause fatty liver disease while making it harder to lose belly fat, even if you don't eat more calories.
This study investigates how trans-fatty acid consumption drives hepatic fat accumulation and reduces visceral fat via GPAM upregulation in metabolic dysfunction-associated steatotic liver disease (MASLD).
Trans-fatty acids increased hepatic GPAM expression, leading to higher liver triglycerides and lower visceral adipose tissue in mice and humans, while GPAM knockdown reversed these effects. Human liver samples confirmed GPAM levels correlate with steatosis severity.
Methods Used
Mice were fed high-fat diets rich in palmitic acid, trans-fatty acids, or oleic acid; Hepa 1-6 cells were exposed to these fatty acids; GPAM was manipulated via overexpression and siRNA knockdown using a pH-sensitive nanodevice; human MASLD liver biopsies were analyzed for GPAM expression.
Main Finding
Trans-fatty acid consumption increased hepatic GPAM expression, which directly caused elevated liver triglycerides and reduced visceral adipose tissue; GPAM knockdown suppressed steatosis and restored visceral fat in mice.
Confidence Level
High — the study uses causal manipulations (siRNA knockdown, overexpression) in both mice and human cells, supported by correlative human tissue data, with consistent findings across models.
Study Flags
Red Flags
- •Human data limited to correlative biopsy analysis
- •No direct measurement of caloric intake control in humans
- •Nanodevice delivery method not fully characterized for long-term safety
Surprising Findings
Trans fats reduced visceral adipose tissue (VAT) while increasing liver fat—opposite of what most high-fat diets do.
Everyone assumes high-fat diets = more belly fat. This study shows trans fats uniquely reroute fat storage, making you 'skinny-fat' with a ticking time bomb in your liver.
Practical Takeaways
Avoid any food with 'partially hydrogenated oils' on the label—even if it says '0g trans fat' (FDA allows up to 0.5g per serving).
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 540 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Moderate probability
on the GRADE evidence scale
This study saw that when mice and human liver cells were fed trans fats, they made more of a protein called GPAM and stored more fat. But it didn't prove that trans fats caused the fat buildup — it just showed they often happened together.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Multi-model approach (in vivo mice, in vitro cells, human tissue) strengthens biological plausibility
- Use of genetic manipulation (siRNA, overexpression) to test mechanistic role of GPAM
- Clear and consistent findings across experimental systems
Weaknesses
- No randomization reported — cannot rule out confounding
- Blinding status unknown — risk of measurement bias
- No sample size justification or power calculation
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The scientists did a good job testing their idea in different ways — in cells, in mice, and in human tissue. But they didn't randomly assign who got what diet, so we can't be sure other things (like genetics or other foods) didn't cause the results. That makes the findings interesting but not totally trustworthy for making health rules.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
19 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample sizeno sample size reported
- Follow-upno follow-up reported
100 / 100
54 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
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 540 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. This study uses animal and in vitro models with no randomization or blinding reported, and includes observational human data without controlled intervention. Without randomization, confounding factors cannot be ruled out, so causation cannot be established.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding statements were disclosed in the provided text, and no industry affiliations or financial ties were identified among the authors.
The study lacks any declared funding sources or conflict of interest statement, which is a limitation for transparency. However, no evidence of industry influence, author employment by companies, or funder involvement in study design or analysis was found in the provided text.
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 Thomas DeLauer cite this study, drawing 1 claim from it.
- Contradicted
Evidence contradicts this claim.
Evidence
Authored by
16 researchersIf this is your work, this is how we attribute it on Fit Body Science. Teruki Miyake is listed as the lead author.