Study analysis · The Journal of Nutrition, Health & Aging · 2023
Eating more carbs could be silently weakening your bones — here's the shocking science.
Swap 5% of your carbs for chicken or cheese, and your bones might get stronger over time.
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 looked at what people ate and how strong their bones were over time, and found that people who ate more carbs tended to have weaker bones, while those who ate more protein and fat tended to have stronger bones. But it didn’t prove that eating more carbs breaks your bones—it just saw a pattern, and other things like how much they moved or how much sun they got could also be involved.
What’s the bottom line?
This study looked at what adults in Mexico ate and how it changed their bone strength over six years.
How strong is this study?
This study did a pretty good job measuring what people ate and how strong their bones were, and followed the same people for years. But since people chose their own diets and weren’t randomly assigned to eat certain foods, we can’t be totally sure the food itself caused the changes—other habits might be the real reason.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
37 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=1317)+20.0/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- 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 560 / 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 is an observational cohort study without randomization or control group; it can identify associations but cannot rule out confounding factors such as lifestyle, genetics, or unmeasured variables that may influence both diet and bone density.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding disclosures were reported in the study text. The study appears independently conducted with no apparent industry influence.
The study was conducted using data from the Health Worker Cohort Study funded by the Mexican Institute of Social Security (IMSS), but no explicit funding statement or conflict of interest disclosure was provided in the text. Authors are affiliated with IMSS, which is a public institution, and no industry ties or financial relationships were disclosed. While the absence of a formal COI statement is a limitation, there is no evidence of bias or industry influence.
Key takeaways
- 01
Eating 5% more carbs made bones weaker; eating 5% more animal protein or fat made bones stronger.
- 02
Replacing carbs with protein or fat helped bones, especially in women.
- 03
Yes — small changes in diet (like swapping a sugary snack for chicken or cheese) could meaningfully affect bone strength over years.
Surprising findings
- Animal fat intake was positively associated with higher bone mineral density — contradicting decades of low-fat dietary advice.Public health guidelines have long demonized saturated fat, yet this study found it linked to stronger bones — especially in women — while carbs were the real villain.
- Fiber improved bone density in women but worsened it in men over time — a rare sex-specific reversal.Fiber is universally praised for health. Finding it harmful to men’s bones over time flips conventional wisdom and suggests gut-bone axis effects differ dramatically by sex.
Practical takeaways
Replace one sugary snack or refined carb serving per day (like a muffin or soda) with a serving of chicken, eggs, cheese, or avocado.
This study was done in Mexican adults — results may not apply to all ethnicities, and long-term effects on heart health are unknown.
medium confidenceWomen over 45 should prioritize animal protein and healthy fats in their diet to help preserve hip and spine bone density.
The study didn't measure vitamin D or calcium intake in detail — these are still critical for bone health and shouldn't be ignored.
medium confidenceMen should be cautious about very high-fiber diets if they're concerned about bone density — especially if they're sedentary or older.
Fiber has many other benefits (gut health, cancer prevention). Don't cut it entirely — just balance it with adequate protein and fat.
low confidenceWhy this study matters
Carbs Are Bone Killers (Seriously)
A 5% increase in daily energy from carbohydrates was linked to measurable bone mineral density (BMD) loss at the hip and femoral neck in both men and women over six years. This wasn't a tiny effect — it was statistically significant and adjusted for age, BMI, calcium, and vitamin D.
Most people think carbs are harmless energy sources, but this study suggests they may be quietly eroding bone strength — especially as we age — without anyone noticing until it's too late.
Animal Protein = Bone Booster
Replacing just 5% of carbohydrate energy with animal protein increased BMD at the hip, femoral neck, and spine — with women seeing the strongest gains. The study specifically highlighted animal (not plant) protein as the driver.
This flips the script on low-protein diets promoted for 'kidney health' — here, more animal protein is tied to stronger bones, especially in women approaching menopause.
Fat Isn't the Enemy — At Least for Bones
Higher intake of animal fat was associated with increased BMD across multiple skeletal sites. Even more surprising: replacing carbs with fat improved bone density — and this effect was strongest in women.
In a world obsessed with low-fat diets, this shows fat — especially from animal sources — might be a silent protector of bone health, contradicting decades of dietary dogma.
Fiber Has a Gender Twist
Cross-sectionally, fiber was linked to higher hip BMD in women — but longitudinally, higher fiber intake predicted lower femoral neck BMD in men. The same nutrient had opposite effects based on sex and time.
This isn't just about 'fiber is good' — it shows nutrition isn't one-size-fits-all. Your gender and how long you eat a certain way matter deeply.
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 looked at what adults in Mexico ate and how it changed their bone strength over six years.
Research results
Eating 5% more carbs made bones weaker; eating 5% more animal protein or fat made bones stronger. Replacing carbs with protein or fat helped bones, especially in women.
What this means - more context
Yes — small changes in diet (like swapping a sugary snack for chicken or cheese) could meaningfully affect bone strength over years.
This study examined how macronutrient intake and substitutions affect bone mineral density (BMD) over six years in a Mexican adult cohort.
Higher carbohydrate intake was associated with reduced BMD, while higher animal protein and fat intake were linked to increased BMD. Substituting carbohydrates with protein or fat improved BMD, especially in women. Fiber showed sex-specific associations: positive cross-sectionally in women, negative longitudinally in men.
Methods Used
Longitudinal analysis of 1,317 Mexican adults (2004–2012) using validated food frequency questionnaires and DXA scans. Hybrid-mixed effects regression models assessed associations, adjusting for age, BMI, physical activity, calcium, vitamin D, and other covariates. Substitution models evaluated isocaloric macronutrient replacements.
Main Finding
A 5% increase in energy from carbohydrates was associated with BMD loss at the total hip and femoral neck in both sexes; replacing 5% carbohydrate energy with animal protein or fat increased BMD at multiple sites, with stronger effects in women.
Confidence Level
Moderate — findings are statistically significant and adjusted for key confounders, but power was below 80% for some macronutrients; observational design limits causal inference.
Study Flags
Red Flags
- •No randomization or intervention
- •Dietary data self-reported via FFQ (potential measurement error)
- •Limited generalizability to non-Mexican populations
Surprising Findings
Animal fat intake was positively associated with higher bone mineral density — contradicting decades of low-fat dietary advice.
Public health guidelines have long demonized saturated fat, yet this study found it linked to stronger bones — especially in women — while carbs were the real villain.
Practical Takeaways
Replace one sugary snack or refined carb serving per day (like a muffin or soda) with a serving of chicken, eggs, cheese, or avocado.
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 560 / 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 looked at what people ate and how strong their bones were over time, and found that people who ate more carbs tended to have weaker bones, while those who ate more protein and fat tended to have stronger bones. But it didn’t prove that eating more carbs breaks your bones—it just saw a pattern, and other things like how much they moved or how much sun they got could also be involved.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Longitudinal design with two time points over 6.7 years
- Large sample size (n=1,317) with both sexes and wide age range
- Use of validated food frequency questionnaire and standardized DXA measurements
Weaknesses
- No randomization or control group
- Dietary intake measured by self-reported FFQ, prone to recall and reporting bias
- Blinding status unknown, potential for measurement bias
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This study looked at what adults in Mexico ate and how it changed their bone strength over six years.
Research results
Eating 5% more carbs made bones weaker; eating 5% more animal protein or fat made bones stronger. Replacing carbs with protein or fat helped bones, especially in women.
What this means - more context
Yes — small changes in diet (like swapping a sugary snack for chicken or cheese) could meaningfully affect bone strength over years.
This study examined how macronutrient intake and substitutions affect bone mineral density (BMD) over six years in a Mexican adult cohort.
Higher carbohydrate intake was associated with reduced BMD, while higher animal protein and fat intake were linked to increased BMD. Substituting carbohydrates with protein or fat improved BMD, especially in women. Fiber showed sex-specific associations: positive cross-sectionally in women, negative longitudinally in men.
Methods Used
Longitudinal analysis of 1,317 Mexican adults (2004–2012) using validated food frequency questionnaires and DXA scans. Hybrid-mixed effects regression models assessed associations, adjusting for age, BMI, physical activity, calcium, vitamin D, and other covariates. Substitution models evaluated isocaloric macronutrient replacements.
Main Finding
A 5% increase in energy from carbohydrates was associated with BMD loss at the total hip and femoral neck in both sexes; replacing 5% carbohydrate energy with animal protein or fat increased BMD at multiple sites, with stronger effects in women.
Confidence Level
Moderate — findings are statistically significant and adjusted for key confounders, but power was below 80% for some macronutrients; observational design limits causal inference.
Study Flags
Red Flags
- •No randomization or intervention
- •Dietary data self-reported via FFQ (potential measurement error)
- •Limited generalizability to non-Mexican populations
Surprising Findings
Animal fat intake was positively associated with higher bone mineral density — contradicting decades of low-fat dietary advice.
Public health guidelines have long demonized saturated fat, yet this study found it linked to stronger bones — especially in women — while carbs were the real villain.
Practical Takeaways
Replace one sugary snack or refined carb serving per day (like a muffin or soda) with a serving of chicken, eggs, cheese, or avocado.
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 560 / 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 looked at what people ate and how strong their bones were over time, and found that people who ate more carbs tended to have weaker bones, while those who ate more protein and fat tended to have stronger bones. But it didn’t prove that eating more carbs breaks your bones—it just saw a pattern, and other things like how much they moved or how much sun they got could also be involved.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Longitudinal design with two time points over 6.7 years
- Large sample size (n=1,317) with both sexes and wide age range
- Use of validated food frequency questionnaire and standardized DXA measurements
Weaknesses
- No randomization or control group
- Dietary intake measured by self-reported FFQ, prone to recall and reporting bias
- Blinding status unknown, potential for measurement bias
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study did a pretty good job measuring what people ate and how strong their bones were, and followed the same people for years. But since people chose their own diets and weren’t randomly assigned to eat certain foods, we can’t be totally sure the food itself caused the changes—other habits might be the real reason.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
37 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=1317)+20.0/20
- Follow-up+10/10
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- 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 560 / 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 is an observational cohort study without randomization or control group; it can identify associations but cannot rule out confounding factors such as lifestyle, genetics, or unmeasured variables that may influence both diet and bone density.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding disclosures were reported in the study text. The study appears independently conducted with no apparent industry influence.
The study was conducted using data from the Health Worker Cohort Study funded by the Mexican Institute of Social Security (IMSS), but no explicit funding statement or conflict of interest disclosure was provided in the text. Authors are affiliated with IMSS, which is a public institution, and no industry ties or financial relationships were disclosed. While the absence of a formal COI statement is a limitation, there is no evidence of bias or industry influence.
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 Shawn Baker MD 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
5 researchersIf this is your work, this is how we attribute it on Fit Body Science. Berenice Rivera‐Paredez is listed as the lead author.
- National Institute of Genomic Medicine
Cited in 1 claim