Ultra-processed foods drive overeating and weight gain: in an NIH randomized trial, people ate about 500 kcal more per day and gained 0.9 kg in two weeks on an ultra-processed diet.
Original statement
الدليل التجريبي الحاسم جاء من تجربة هول العشوائية ... فالأكل من الأطعمة فائقة المعالجة دفعهم لاستهلاك 508 سعرة زائدة يومياً وزيادة 0.9 كغ في أسبوعين، بينما خسر نفس الأشخاص 0.9 كغ على الحمية غير المُعالَجة.
verbatim according to source. Translation by the project; the Arabic wording is authoritative.
Translation
Ultra-processed foods drive overeating and weight gain: in an NIH randomized trial, people ate about 500 kcal more per day and gained 0.9 kg in two weeks on an ultra-processed diet.
Origin
- Source status
- Archive editors
- Attribution
- Archive editors (study selection and narrative are the archive's, not necessarily Elawady's)
- Origin
- https://eltayebat.com/rule/ultra-processed-foods/
- Attribution uncertainty
- The archive homepage states that the forbidden-food section is supported by research 'independently of Dr. Diaa's words'. No evidence was found that Elawady himself cited these studies.
- Claimed mechanism
Hyper-palatability, energy density, eating rate (not specified by archive).
- Claimed health effect
Excess energy intake, weight gain, obesity.
- Population concerned
Adults, children
- Geographic restriction by Elawady
none found
Scientific assessment
Mostly true – Correct at its core, but with limitations or minor inaccuracies.
Certainty of evidence: moderate – Further research may still affect the assessment.
1. What was claimed?
UPF diets cause overeating and weight gain.
2. What is demonstrably correct?
Hall 2019 (A-UPF-01): +508 ± 106 kcal/day, +0.9 kg vs -0.9 kg. Dicken 2025 (I-UPF-01): within guideline-compliant diets, weight loss was greater on minimally processed food (-2.06% vs -1.05%; difference -1.01%, 95% CI -1.87 to -0.14).
3. What is wrong or exaggerated?
Calling one 20-person, 4-week inpatient trial 'decisive' is an overstatement; long-term effects are not tested in trials.
4. What remains unclear?
Which features of UPF drive the effect.
5. Which studies support it?
A-UPF-01, A-UPF-08, A-UPF-09, A-UPF-10, I-UPF-01.
6. Which studies contradict it?
None contradicting; limitations are size and duration.
7. What applies to Germany and Europe?
Applicable; I-UPF-01 was conducted in England.
8. What is known about Egypt?
No Egypt-specific data.
9. What practical conclusion is appropriate?
Choosing mainly minimally processed foods may help weight control.
Assessment details
- Rationale for certainty of evidence
Two randomized crossover feeding trials (US inpatient, n=20, 2 weeks per diet; UK outpatient, n=55, 8 weeks per diet) point the same way; supported by cohorts (A-UPF-08, A-UPF-09) and a systematic review in children (A-UPF-10). Trials are short and small; mechanisms are unresolved.
- Source quality
Archive reports Hall 2019 accurately; 'the decisive evidence' overstates a 20-person, 4-week trial.
- Regional transferability
High: the 2025 UK trial (I-UPF-01) was conducted in England within national dietary guidelines.
- Individual exceptions
Responses varied between individuals.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 25 October 2026 provisional
In plain language
In a US hospital experiment, 20 people ate about 500 calories more each day when given ultra-processed food and gained weight, while they lost weight on unprocessed food. A larger 2025 trial in England found more weight loss on a minimally processed diet, even when both diets followed national healthy-eating advice. These trials are short, but they support the archive's point.
Studies on this claim
Studies supporting the claim (5)
-
Ultra-processed vs unprocessed diet in hospital
Hall KD et al.. Cell Metab 2019 · PMID 31105044 · DOI 10.1016/j.cmet.2019.05.008Randomised controlled trialcited by the Tayebat archivefull text checked★ key studyPeople ate about 500 calories more per day and gained weight on ultra-processed food.
Does the study support the specific claim? Yes · 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?
Do ultra-processed foods affect energy intake?
- How was the study done?
Inpatient randomized crossover trial, 2 weeks per diet, ad libitum.
- How many people, animals or samples were studied?
20; Weight-stable adults, mean age 31, BMI 27
- What was actually found?
Energy intake +508 ± 106 kcal/day on UPF (p=0.0001); carbohydrate +280, fat +230 kcal/day; protein unchanged; weight +0.9 ± 0.3 kg (UPF) vs -0.9 ± 0.3 kg (unprocessed).
- How large was the observed effect?
+508 kcal/day; +0.9 kg vs -0.9 kg
- What do the results mean in everyday life?
Ultra-processed food can make people eat more.
- What are the study's limitations?
Only 20 people, 2 weeks per diet, in hospital conditions; no washout between diets; participants knew which diet they ate; the cause of the extra eating (e.g. energy-dense food, faster eating) is not clear.
- What does it say about Elawady's specific claim?
Core evidence for C-UPF-02.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Long-term health outcomes.
-
Ultra-processed food and weight gain in Spain
Mendonça RD et al.. Am J Clin Nutr 2016 · PMID 27733404 · DOI 10.3945/ajcn.116.135004Cohort studycited by the Tayebat archiveabstract only checkedHighest consumers had 26% higher risk of becoming overweight.
Does the study support the specific claim? Yes · 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?
Is UPF associated with incident overweight/obesity?
- How was the study done?
Prospective cohort, FFQ.
- How many people, animals or samples were studied?
8,451; 1,939 incident cases; Middle-aged graduates not overweight at baseline
- What was actually found?
Highest vs lowest quartile HR 1.26 (1.10-1.45); P trend 0.001.
- How large was the observed effect?
HR 1.26 (1.10-1.45)
- What do the results mean in everyday life?
Association.
- What are the study's limitations?
NOVA misclassification possible; Residual confounding; Self-reported diet
- What does it say about Elawady's specific claim?
Supports C-UPF-02.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Causation.
-
Ultra-processed food and BMI in France
Beslay M et al.. PLoS Med 2020 · PMID 32853224 · DOI 10.1371/journal.pmed.1003256Cohort studycited by the Tayebat archiveabstract only checkedEach 10% more ultra-processed food: 11% higher risk of overweight.
Does the study support the specific claim? Yes · 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?
Is UPF associated with BMI change and overweight/obesity?
- How was the study done?
Prospective cohort with repeated 24-h records.
- How many people, animals or samples were studied?
110,260; 7,063 overweight and 3,066 obese incident; Adults, 78% women
- What was actually found?
BMI gain beta 0.02 per 10%; overweight HR 1.11 (1.08-1.14); obesity HR 1.09 (1.05-1.13).
- How large was the observed effect?
HR 1.11 overweight
- What do the results mean in everyday life?
Association.
- What are the study's limitations?
NOVA misclassification possible; Residual confounding; Self-reported diet; Selection bias (authors)
- What does it say about Elawady's specific claim?
Supports C-UPF-02.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Causation.
-
Ultra-processed food and body fat in children
Costa CS et al.. Public Health Nutr 2018 · PMID 28676132 · DOI 10.1017/S1368980017001331Systematic reviewcited by the Tayebat archiveabstract only checkedMost studies found more body fat in children eating more ultra-processed foods, including sweets and soft drinks.
Does the study support the specific claim? Yes · Methodological quality: low · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Is UPF associated with body fat in children/adolescents?
- How was the study done?
Systematic review (no meta-analysis).
- How many people, animals or samples were studied?
26 studies (15 cohorts); Healthy children and adolescents
- What was actually found?
Most studies of UPF groups and soft drinks found positive associations with body fat.
- How large was the observed effect?
Not pooled
- What do the results mean in everyday life?
Association.
- What are the study's limitations?
No pooling; Heterogeneous exposures
- What does it say about Elawady's specific claim?
Supports C-UPF-02.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Causation.
-
Ultra-processed vs minimally processed healthy diets in England
Dicken SJ et al.. Nat Med 2025 · PMID 40760353 · DOI 10.1038/s41591-025-03842-0Randomised controlled trialindependent cross-checkfull text checked★ key studyBoth diets led to weight loss, but about twice as much on minimally processed food.
Does the study support the specific claim? Yes · 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?
Effect of UPF vs MPF within national dietary guidelines on weight.
- How was the study done?
2x2 crossover randomized controlled feeding trial, 8 weeks per diet, ad libitum.
- How many people, animals or samples were studied?
55 randomized; 50 ITT; Adults with BMI 25-<40 and habitual UPF >=50% kcal
- What was actually found?
MPF -2.06% (-2.99 to -1.13); UPF -1.05% (-1.98 to -0.13); difference -1.01% (-1.87 to -0.14), P=0.024; Cohen's d -0.48. Mild GI adverse events common on both.
- How large was the observed effect?
-2.06% vs -1.05% weight
- What do the results mean in everyday life?
Processing level may matter even in healthy diets.
- What are the study's limitations?
About 50 people, mostly women and health workers, 8 weeks per diet; the difference between diets was about 1 kg; dropouts happened only on the minimally processed diet; the order of the diets influenced the result.
- What does it say about Elawady's specific claim?
Supports C-UPF-02 (replicates direction of Hall 2019).
- Do the results apply to Germany and Europe?
High (England).
- What can explicitly not be concluded from this study?
It cannot show long-term effects on weight or disease, nor that UPF are harmful when a diet otherwise follows healthy guidance (both diets led to weight loss).
No study in this group is marked as key.
Studies contradicting or limiting the claim (0)
No studies in this group.
Studies with mixed or unclear results (0)
No studies in this group.
Regional context
Germany / EU
Applicable; I-UPF-01 was conducted in England.
Egypt
No Egypt-specific data.
What applies in my country?
General scientific assessment
Mostly true Trials support that UPF diets lead to higher calorie intake and less weight loss; the evidence is short-term.
The following areas of food safety are relevant to this statement:
- Additives and processing
- Controls, imports, recalls, labelling
Choose a country to see the checked information for it.
Limits: legal rules describe what is allowed, not what every single food contains. Measurement data come from samples and are meaningful only together with their method details.
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References
- Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake.. Hall KD et al.. Cell Metab 2019 · PMID 31105044 · DOI 10.1016/j.cmet.2019.05.008
- Ultraprocessed food consumption and risk of overweight and obesity: the University of Navarra Follow-Up (SUN) cohort study.. Mendonça RD et al.. Am J Clin Nutr 2016 · PMID 27733404 · DOI 10.3945/ajcn.116.135004
- Ultra-processed food intake in association with BMI change and risk of overweight and obesity: A prospective analysis of the French NutriNet-Santé cohort.. Beslay M et al.. PLoS Med 2020 · PMID 32853224 · DOI 10.1371/journal.pmed.1003256
- Consumption of ultra-processed foods and body fat during childhood and adolescence: a systematic review.. Costa CS et al.. Public Health Nutr 2018 · PMID 28676132 · DOI 10.1017/S1368980017001331
- Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial.. Dicken SJ et al.. Nat Med 2025 · PMID 40760353 · DOI 10.1038/s41591-025-03842-0