Nezam El-Tayebat Fact CheckA scientific assessment of the “نظام الطيبات” nutrition system
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Potentially true Overinterpreted Certainty of evidence: moderate provisional C-SYS-02

Food is the first (leading) cause of modern (non-communicable) diseases.

In short: This claim is partly true. Poor diet is one of the leading causes of chronic disease worldwide and also raises blood pressure and blood sugar, but the newest global analyses rank high blood pressure, air pollution and tobacco ahead of diet, so 'the first cause' overstates the evidence.
Conclusion: Poor diet is one of the leading causes of chronic disease, but the newest global analyses rank high blood pressure, air pollution and tobacco ahead of it, so 'the first cause' overstates the evidence.
  1. Original statement
  2. Scientific assessment
  3. Scientific evidence in detail
  4. In plain language
  5. Studies on this claim
  6. Regional context
  7. What applies in my country?
  8. References

Original statement

الغذاء عند د. ضياء هو السبب الأول للأمراض المستحدثة

verbatim according to source. Translation by the project; the Arabic wording is authoritative.

Translation

Food is the first (leading) cause of modern (non-communicable) diseases.

Origin

Source status
Archive editors
Attribution
Archive editors summarising Elawady's view
Origin
https://eltayebat.com/
Attribution uncertainty
Written by archive operators; not attributed to Elawady.
Population concerned

General

Geographic restriction by Elawady

none found

Scientific assessment

Potentially true – Some evidence points in favour of the statement, but it is not sufficient for a clear judgement.

Certainty of evidence: moderate – Further research may still affect the assessment.

1. What was claimed?

Food is the primary cause of modern diseases.

2. What is demonstrably correct?

Diet is among the leading risk factors for chronic disease: GBD 2017 attributed 11 million deaths (22% of adult deaths) to dietary risks (I-SYS-01); in GBD 2019 and 2021 dietary risks remained a leading Level 2 cluster (I-SYS-02, I-SYS-101), and diet also raises blood pressure, BMI and blood glucose, which are counted separately.

3. What is wrong or exaggerated?

'First cause' is not supported by the newest analyses: in GBD 2021 the leading single risks were particulate air pollution (8.0% of DALYs), high systolic blood pressure (7.8%) and smoking (5.7%), and dietary risks ranked fifth among Level 2 clusters (I-SYS-101); in GBD 2023 high blood pressure, air pollution, high fasting glucose and smoking led (I-SYS-102). In a large UK cohort, smoking, socioeconomic factors and physical activity were the strongest drivers of mortality (I-SYS-103). The dietary risks that matter most (high sodium, low whole grains and fruit; I-SYS-01) are not those the system emphasises.

4. What remains unclear?

Ranking diet vs blood pressure overlaps because diet contributes to blood pressure.

5. Which studies support it?

I-SYS-01; partly I-SYS-02 and I-SYS-101 (diet a leading cluster).

6. Which studies contradict it?

I-SYS-02, I-SYS-101, I-SYS-102, I-SYS-103, I-CAN-03.

7. What applies to Germany and Europe?

Same global evidence.

8. What is known about Egypt?

Same.

9. What practical conclusion is appropriate?

Diet is a major lever for preventing chronic disease, together with not smoking, blood-pressure control, clean air, physical activity and limiting alcohol.

Assessment details

Rationale for certainty of evidence

Moderate: GBD 2017 ranked suboptimal diet first (22% of adult deaths; I-SYS-01), but the newer GBD rounds rank it lower - third (males) and second (females) for deaths and fifth for DALYs in GBD 2019 (I-SYS-02), fifth Level 2 risk for DALYs in GBD 2021 (I-SYS-101), with high systolic blood pressure, air pollution, high fasting glucose and smoking as leading single risks in GBD 2023 (I-SYS-102). Diet partly acts through blood pressure, BMI and glucose, so its total role is larger than its separate rank.

Source quality

Archive editorial.

Regional transferability

High.

Regional scope of the claim
general (biological/medical)
Last reviewed
26 October 2026 provisional

Scientific evidence in detail

Overinterpreted – A real finding exists, but the claim draws more from it than the data allow (e.g. association taken as cause, animal data applied to humans, small effect presented as large).

Research question: Is diet the leading (first) risk factor for non-communicable disease burden worldwide?

Research question in detail (PECO)
Population
Global population
Intervention or exposure
Dietary risks
Comparison
Other risk factors (blood pressure, tobacco, air pollution, glucose, BMI)
Geographic scope
global incl. Egypt and Europe
Outcomes
  • Attributable deaths
  • Attributable DALYs
  • Ranking

Study results as reported by the authors. Our assessment follows below.

What speaks for the claim?

What speaks against the claim?

What does the overall evidence say?

Editorial assessment based on the studies above – not itself a study result.

Which position is better supported?

Diet is one of the leading modifiable risk clusters for non-communicable disease and contributes to high blood pressure, glucose and BMI, but in the newest global analyses it is not the single first cause; air pollution, high blood pressure and tobacco rank higher.

Why some studies weigh more

Newer GBD rounds (2019, 2021, 2023) supersede GBD 2017 and consistently rank diet below blood pressure and tobacco; mediation means diet's total role is larger than its separate ranking.

Is a causal relationship established? Probable Causal evidence for many dietary risks is from cohorts and some RCTs (e.g. sodium); weaker than for tobacco.

Remaining uncertainty

Ranking depends on how risks are grouped and on mediation assumptions.

Justified conclusion

Food is a leading cause of modern diseases, but calling it 'the first cause' overstates current evidence.

Why do studies seem to disagree?

GBD 2017 (diet first) vs GBD 2019-2023 (diet second to fifth) differ because of updated relative risks and TMRELs (diet burden revised 29.7% downward) and different grouping levels; not a contradiction in data quality.

Does this depend on the country?
General biological effects
Universal human biology; applies in Egypt, Germany and elsewhere.
Eating habits
Not decisive for this claim.
Origin of the food
Not relevant.
Contaminants
Not relevant.
National production conditions
Not relevant.
Legal rules
Not relevant.
Actual monitoring data
GBD analyses include Egypt; Egypt-specific rankings were not extracted.

A regional difference that changes the conclusion is not supported by robust data.

Statistical re-check
  • Share of DALYs attributable to all quantified risks – 1.27/2.80 = 45.4%. recalculated
Certainty of the overall evidence (GRADE, simplified)
Main outcome
Rank of diet among risk factors for NCD burden
Starting level
high (randomised trials)
Reasons for downgrading
  • inconsistency (rankings differ between GBD rounds)
  • indirectness (model-based attribution)
Result
moderate

Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.

Clinical guidelines and official statements checked
  • IARC/WHO and European Commission (European Code Against Cancer, 5th ed.): ECAC5 - diet, excess body weight, physical activity, sedentary behavior, breastfeeding, and cancer (Mol Oncol 2026; PMID 41542809) (2026) · Original publication
    Eat whole grains, vegetables, legumes and fruits as a major part of the daily diet; limit red meat and avoid processed meat; limit sugary drinks and ultra-processed foods; dairy and supplements not included because evidence is heterogeneous.
  • WHO: Cancer - fact sheet (2026) · Original publication
    About 38% of cancers can be prevented by avoiding risk factors (tobacco, alcohol, unhealthy diet, inactivity, air pollution); about 10% are attributable to infections; many cancers can be cured if detected early and treated effectively.
Search strategy

Documented literature searches for this review (search strings in the original database syntax).

DatabaseDateSearchLooking forHitsIncluded
Europe PMC26 October 2026TITLE:"risk factors" AND TITLE:"204 countries" AND (GBD 2021 OR GBD 2023) AND JOURNAL:"Lancet"both directions2
Europe PMC26 October 2026(TITLE:"dietary risks" OR TITLE:"suboptimal diet" OR TITLE:"dietary risk") AND (TITLE:"global burden" OR TITLE:"GBD") AND PUB_YEAR:[2021 TO 2026]supporting evidence46
Europe PMC26 October 2026TITLE:"Integrating the environmental and genetic architectures of aging and mortality"both directions1
Europe PMC26 October 2026(Tayebat OR Tayibat OR Elawady OR "El-Awady diet" OR "Al-Awady")both directions377
PubMed26 October 2026("dietary risks"[tiab]) AND ("Global Burden of Disease"[tiab]) AND (deaths[tiab]) AND (leading[tiab])supporting evidence56
PubMed26 October 2026("risk factors"[ti]) AND ("Global Burden of Disease Study 2021"[tiab] OR "GBD 2021"[tiab] OR "GBD 2023"[tiab]) AND Lancet[ta]contradicting evidence4

Open questions

Egypt-specific GBD rankings.

How deeply was this checked?

7 linked studies: 3 checked in full text (2 of them with a structured risk-of-bias assessment), 4 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.

Last scientific review: 26 October 2026

History of the verdict
  1. 25 October 2026 · Phase 1 · Initial assessment: Mostly true (moderate)
  2. 26 October 2026 · Phase 4 (systematic evidence review) · Verdict changed: Mostly true (moderate) → Potentially true (moderate)
    Verdict changed from “Mostly true” to “Potentially true”. The earlier verdict relied mainly on GBD 2017, which ranked diet first. The two newer GBD rounds (2021, I-SYS-101; 2023, I-SYS-102), together with GBD 2019 (I-SYS-02), consistently rank high blood pressure, air pollution and tobacco ahead of diet, and an exposome study (I-SYS-103) identifies smoking, socioeconomic status and activity as the strongest drivers. Diet remains a leading, partly upstream cause, so the claim is partly true but 'first cause' is overstated.
    New sources: I-SYS-101 I-SYS-102 I-SYS-103

In plain language

The archive says food is the first cause of modern diseases. Food is indeed one of the most important causes, and an older global study ranked it first. Newer updates of the same project rank high blood pressure, air pollution and smoking higher, with diet among the top five - although diet itself also raises blood pressure and blood sugar. The dietary problems that matter most are too much salt and too few whole grains and fruits.

Studies on this claim

Studies supporting the claim (1)

  • Poor diet is linked to about one in five adult deaths worldwide

    GBD 2017 Diet Collaborators. Lancet 2019 · PMID 30954305 · DOI 10.1016/S0140-6736(19)30041-8
    Risk assessmentindependent cross-checkfull text checked★ key study

    11 million deaths in 2017 were attributed to dietary risks, mainly too much salt and too few whole grains and fruits.

    Diet responsible for ~22% of adult deaths

    Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Quantify diet-attributable deaths.

    How was the study done?

    GBD comparative risk assessment.

    How many people, animals or samples were studied?

    195 countries.

    What was actually found?

    11 million deaths (22%).

    How large was the observed effect?

    Sodium 3 m, whole grains 3 m, fruit 2 m deaths.

    What do the results mean in everyday life?

    Eat more whole grains and fruit, less salt.

    What are the study's limitations?

    Observational inputs.

    What does it say about Elawady's specific claim?

    Diet matters; the main dietary problems differ from the system's forbidden list.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    That food is the sole cause.

    Scientific details →

Studies contradicting or limiting the claim (5)

  • High blood pressure and tobacco are the top risk factors for death worldwide

    GBD 2019 Risk Factors Collaborators. Lancet 2020 · PMID 33069327 · DOI 10.1016/S0140-6736(20)30752-2
    Risk assessmentindependent cross-checkfull text, structured risk-of-bias assessment★ key study

    In 2019, high blood pressure was linked to 10.8 million and tobacco to 8.7 million deaths.

    Top Level-2 risks: high SBP, tobacco

    Does the study support the specific claim? No · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Rank risk factors.

    How was the study done?

    GBD 2019.

    How many people, animals or samples were studied?

    204 countries.

    What was actually found?

    High blood pressure and tobacco lead; dietary risks rank among the top five; all 87 risks together explain 47.8% of global disease burden.

    How large was the observed effect?

    19.2% and 15.4% of deaths.

    What do the results mean in everyday life?

    Check blood pressure; avoid tobacco; diet is one lever.

    What are the study's limitations?

    Modelling.

    What does it say about Elawady's specific claim?

    Multiple causes.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    Individual risk.

    Scientific details →

  • Smoking, alcohol and excess weight lead global avoidable cancer deaths

    GBD 2019 Cancer Risk Factors Collaborators. Lancet 2022 · PMID 35988567 · DOI 10.1016/S0140-6736(22)01438-6
    Risk assessmentindependent cross-checkfull text, structured risk-of-bias assessment

    44% of cancer deaths worldwide in 2019 were attributable to known risk factors, smoking first; diet accounted for about 5-6% of cancer burden.

    For cancer, smoking leads

    Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Global attributable cancer burden.

    How was the study done?

    GBD modelling.

    How many people, animals or samples were studied?

    204 countries.

    What was actually found?

    4.45 million cancer deaths (44.4%) attributable to modelled risks in 2019; tobacco 33.9% of male and 10.7% of female cancer DALYs; dietary risks 5.9% and 5.1%.

    How large was the observed effect?

    4.45 million deaths.

    What do the results mean in everyday life?

    Avoid tobacco and alcohol, keep healthy weight.

    What are the study's limitations?

    Model-based estimates; sparse data in many countries; infections and UV not included.

    What does it say about Elawady's specific claim?

    Diet is one factor among several.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    That the remaining 56% of cancer deaths have no external cause (infections and UV were not modelled); individual risk for a given person.

    Scientific details →

  • Global causes of ill health in 2021

    GBD 2021 Risk Factors Collaborators. Lancet 2024 · PMID 38762324 · DOI 10.1016/S0140-6736(24)00933-4
    Risk assessmentindependent cross-checkabstract checked★ key study

    Air pollution, high blood pressure and smoking were the top single risks; poor diet as a group ranked fifth.

    Diet fifth-leading Level 2 risk for DALYs in 2021

    Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Rank risk factors worldwide.

    How was the study done?

    Global modelling study.

    How many people, animals or samples were studied?

    204 countries.

    What was actually found?

    Air pollution and high blood pressure lead.

    How large was the observed effect?

    PM 8.0%, SBP 7.8%, smoking 5.7% of DALYs.

    What do the results mean in everyday life?

    Diet matters a lot but is not the only or first cause.

    What are the study's limitations?

    Model-based.

    What does it say about Elawady's specific claim?

    Partly contradicts 'food is the first cause'.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    Exact causal shares.

    Scientific details →

  • Global health 2023

    GBD 2023 Disease and Injury and Risk Factor Collaborators. Lancet 2025 · PMID 41092926 · DOI 10.1016/S0140-6736(25)01637-X
    Risk assessmentindependent cross-checkabstract checked★ key study

    About half of all ill health is linked to known risk factors; high blood pressure, air pollution, high blood sugar and smoking lead.

    Top single risks are SBP, PM, FPG, smoking

    Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Global burden 2023.

    How was the study done?

    Modelling.

    How many people, animals or samples were studied?

    204 countries.

    What was actually found?

    Half of burden from known risks.

    How large was the observed effect?

    1.27/2.80 billion DALYs.

    What do the results mean in everyday life?

    Many causes besides food.

    What are the study's limitations?

    Model-based.

    What does it say about Elawady's specific claim?

    Contradicts food-only explanations.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    Unmeasured causes.

    Scientific details →

  • Environment matters more than genes for early death

    Argentieri MA et al.. Nat Med 2025 · PMID 39972219 · DOI 10.1038/s41591-024-03483-9
    Cohort studyindependent cross-checkabstract checked★ key study

    Lifestyle and living conditions explained 17% of variation in mortality, genes less than 2%; smoking and social factors led.

    Diet not among the strongest drivers of ageing/mortality in this analysis

    Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Compare genes and environment.

    How was the study done?

    UK Biobank cohort.

    How many people, animals or samples were studied?

    ~490,000 adults.

    What was actually found?

    Environment explains more.

    How large was the observed effect?

    17 vs <2 points.

    What do the results mean in everyday life?

    Disease is mostly not fate, but food is only one part.

    What are the study's limitations?

    Observational.

    What does it say about Elawady's specific claim?

    Partly supports, partly contradicts.

    Do the results apply to Germany and Europe?

    Moderate-high.

    What can explicitly not be concluded from this study?

    Role of food contaminants.

    Scientific details →

Studies with mixed or unclear results (1)

  • European Code Against Cancer 2026: diet advice

    Leitzmann MF et al.. Mol Oncol 2026 · PMID 41542809 · DOI 10.1002/1878-0261.70201
    Guideline / position statementindependent cross-checkabstract checked★ key study

    Europe's cancer code advises eating whole grains, vegetables, legumes and fruit and limiting processed meat, sugary drinks and ultra-processed food.

    Diet is an important but not the sole modifiable cancer risk

    Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim

    Original publication · Scientific details

    Study explained simply
    What did the researchers want to find out?

    Update EU cancer prevention advice.

    How was the study done?

    Expert review.

    How many people, animals or samples were studied?

    Not applicable.

    What was actually found?

    Plant-rich diet, less processed meat and sugary drinks.

    How large was the observed effect?

    Not applicable.

    What do the results mean in everyday life?

    Clear, evidence-based prevention rules.

    What are the study's limitations?

    Mostly observational evidence.

    What does it say about Elawady's specific claim?

    Supports parts of the system and contradicts its legume/vegetable bans.

    Do the results apply to Germany and Europe?

    High.

    What can explicitly not be concluded from this study?

    Effects of the Tayebat lists themselves.

    Scientific details →

Regional context

Germany / EU

Same global evidence.

Egypt

Same.

What applies in my country?

General scientific assessment

Potentially true Poor diet is one of the leading causes of chronic disease, but the newest global analyses rank high blood pressure, air pollution and tobacco ahead of it, so 'the first cause' overstates the evidence.

This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.

References

  1. Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.. GBD 2017 Diet Collaborators. Lancet 2019 · PMID 30954305 · DOI 10.1016/S0140-6736(19)30041-8
  2. Global burden of 87 risk factors in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019.. GBD 2019 Risk Factors Collaborators. Lancet 2020 · PMID 33069327 · DOI 10.1016/S0140-6736(20)30752-2
  3. The global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019.. GBD 2019 Cancer Risk Factors Collaborators. Lancet 2022 · PMID 35988567 · DOI 10.1016/S0140-6736(22)01438-6
  4. Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021.. GBD 2021 Risk Factors Collaborators. Lancet 2024 · PMID 38762324 · DOI 10.1016/S0140-6736(24)00933-4
  5. Burden of 375 diseases and injuries, risk-attributable burden of 88 risk factors, and healthy life expectancy in 204 countries and territories, including 660 subnational locations, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023.. GBD 2023 Disease and Injury and Risk Factor Collaborators. Lancet 2025 · PMID 41092926 · DOI 10.1016/S0140-6736(25)01637-X
  6. Integrating the environmental and genetic architectures of aging and mortality.. Argentieri MA et al.. Nat Med 2025 · PMID 39972219 · DOI 10.1038/s41591-024-03483-9
  7. European Code Against Cancer, 5th edition - diet, excess body weight, physical activity, sedentary behavior, breastfeeding, and cancer.. Leitzmann MF et al.. Mol Oncol 2026 · PMID 41542809 · DOI 10.1002/1878-0261.70201

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