Antibiotics make people (especially children) gain weight by altering gut bacteria, as they do in fattened poultry; early-childhood antibiotic courses raise obesity risk.

Original statement

المضادات الحيويه بتوزن بتزود الوزن اه لانها بتاثر على المجتمع البكتيري بتاع قولونك وامعائك من الاخر كده فبتخن عشان كده العيال الصغيره لما بتضرب مضادات حيويه جه دور كحه اخد مضاد حيوي ف تلاقي الواد تخن

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

Translation

Antibiotics make people (especially children) gain weight by altering gut bacteria, as they do in fattened poultry; early-childhood antibiotic courses raise obesity risk.

Origin

Source status

Video transcript (own words)

Attribution

Elawady (machine transcript)

Video

Dr Diaa Al Awady د ضياء العوضي is live! مصدر الغذاء الوريد البابي (Open source)

Published

27 July 2025

Timestamp

0:50:11 (location in the original video’s automatic YouTube caption track; confirms where the words occur, not who speaks)

Attribution uncertainty

Archive transcript (YouTube CC or AI-generated); wording may contain transcription errors; no timestamps; 'published' is the date listed by the archive. Passage read in context.

Claimed mechanism

Altered gut microbiota changes energy metabolism (growth-promotion effect known from livestock).

Claimed health effect

Obesity.

Population concerned

Children

Geographic restriction by Elawady

none found

Diverging source versions

Scientific assessment

Unclear / insufficient evidence – The data do not allow an assessment either way.

Certainty of evidence: low – Further research is likely to change the assessment considerably.

1. What was claimed?

Antibiotics cause weight gain via gut bacteria.

2. What is demonstrably correct?

Antibiotics alter gut bacteria (see C-ABX-04). In randomised trials in children in low- and middle-income countries, antibiotics increased weight gain by 23.8 g/month (4.3-43.3) (I-ABX-111) - a growth effect comparable in direction to livestock growth promotion. Observational studies show a small association between early antibiotic courses and later overweight: Bailey 2014 RR 1.11 for >=4 courses (A-ABX-01); PCORnet BMI z +0.04, OR 1.05 (I-ABX-110); register cohort of 33,095 children aHR 1.20 for obesity (I-ABX-113); meta-analyses OR 1.11 (I-ABX-05) and postnatal OR 1.09, >=4 courses OR 1.31, very low certainty (I-ABX-04). Mice: continuous low-dose penicillin in early life increased adiposity via the microbiota (A-ABX-03).

3. What is wrong or exaggerated?

Within families the association disappears: Danish sibling analysis overweight HR 1.02 (0.86-1.22) versus 1.34 in the whole population (I-ABX-114); Dutch twin study OR 1.00 (0.90-1.12) with null co-twin analyses (I-ABX-112). The largest single cohort found only a very small difference (about 1 percentage point more overweight; I-ABX-110). The RCT weight gain concerns undernourished, infection-burdened children, where it is a benefit, not obesity (I-ABX-111). The mouse model used continuous sub-therapeutic doses (A-ABX-03), unlike treatment courses. 'You see the boy get fat' is anecdotal.

4. What remains unclear?

Whether repeated broad-spectrum courses in the first year have a small causal effect that family designs cannot detect.

5. Which studies support it?

A-ABX-01, I-ABX-05, I-ABX-110, I-ABX-113 (small associations); A-ABX-03 (mouse growth-promoter model, mechanistic only); partly I-ABX-111 (weight gain in RCTs in undernourished children), A-ABX-02 and I-ABX-04.

6. Which studies contradict it?

I-ABX-114 (Danish sibling analysis: overweight HR 1.02, 0.86-1.22), I-ABX-112 (Dutch twins: OR 1.00, 0.90-1.12); I-ABX-04 (certainty very low).

7. What applies to Germany and Europe?

European family-based studies (Denmark, I-ABX-114; Netherlands, I-ABX-112) find no association within families; UK ALSPAC found only a transient association (A-ABX-02). Antibiotic growth promoters in animal feed have been banned in the EU since 2006.

8. What is known about Egypt?

No Egyptian data were reviewed.

9. What practical conclusion is appropriate?

Avoid unnecessary antibiotics in infants for many reasons (resistance, side effects), but fear of weight gain is not a reason to withhold antibiotics from a child with a bacterial infection that needs treatment.

Assessment details

Rationale for certainty of evidence

Conventional cohorts and meta-analyses show small, consistent associations (e.g. OR 1.05 in 362,550 US children, I-ABX-110; OR 1.09 postnatal, very low certainty, I-ABX-04). However, two large family-based studies find no association after controlling for shared family factors: Danish siblings, overweight HR 1.34 -> 1.02 (0.86-1.22) (I-ABX-114); Dutch twins, OR 1.00 (0.90-1.12) (I-ABX-112). RCTs show antibiotics increase weight gain only in undernourished children in low- and middle-income countries (I-ABX-111). Causation for obesity is therefore not established.

Source quality

Elawady's statement is a strong causal claim; archive cites the best available data accurately.

Regional transferability

Moderate.

Individual exceptions

Effect per child is small; many children receive antibiotics without becoming obese.

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: In children, does antibiotic exposure in early life cause later overweight or obesity through gut microbiota changes, as antibiotic growth promoters do in livestock?

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

Open questions

Whether repeated broad-spectrum courses in the first year have a small causal effect; studies with negative-control exposures.

How deeply was this checked?

10 linked studies: 3 checked in full text (2 of them with a structured risk-of-bias assessment), 7 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

In plain language

Children who received antibiotics as babies are, on average, very slightly heavier later. But when researchers compared brothers and sisters, or twins, the difference disappeared. This suggests that family factors and frequent infections, not the antibiotics themselves, explain most of the link. In poor countries, antibiotics help undernourished children grow, which is a benefit. It is not shown that antibiotics make children obese.

Studies on this claim

Regional context

Germany / EU

European family-based studies (Denmark, I-ABX-114; Netherlands, I-ABX-112) find no association within families; UK ALSPAC found only a transient association (A-ABX-02). Antibiotic growth promoters in animal feed have been banned in the EU since 2006.

Egypt

No Egyptian data were reviewed.

What applies in my country?

General scientific assessment

Unclear / insufficient evidence Not established: the small link between early antibiotics and later weight largely disappears in sibling and twin studies, so antibiotics are not shown to make children fat.

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. Association of antibiotics in infancy with early childhood obesity.. Bailey LC et al.. JAMA Pediatr 2014 · PMID 25265089 · DOI 10.1001/jamapediatrics.2014.1539
2. Altering the intestinal microbiota during a critical developmental window has lasting metabolic consequences.. Cox LM et al.. Cell 2014 · PMID 25126780 · DOI 10.1016/j.cell.2014.05.052
3. Antibiotic exposure in early life and childhood overweight and obesity: A systematic review and meta-analysis.. Rasmussen SH et al.. Diabetes Obes Metab 2018 · PMID 29359849 · DOI 10.1111/dom.13230
4. Early Antibiotic Exposure and Weight Outcomes in Young Children.. Block JP et al.. Pediatrics 2018 · PMID 30381474 · DOI 10.1542/peds.2018-0290
5. Early-life antibiotic exposure and the risk of overweight and obesity in children.. Ainonen S et al.. Pediatr Res 2026 · PMID 41792341 · DOI 10.1038/s41390-026-04841-8
6. Early-life antibiotic use and children with overweight and obesity: a Dutch twin cohort study.. Feil RS et al.. Int J Obes (Lond) 2026 · PMID 42457938 · DOI 10.1038/s41366-026-02164-6
7. Use of antibiotics in early life and development of diseases in childhood: nationwide registry study.. Brandt S et al.. BMJ Med 2025 · PMID 40519361 · DOI 10.1136/bmjmed-2024-001064
8. Early-life exposure to antibiotics and excess body weight in childhood and adolescence: A systematic review and meta-analysis.. Chagas AP et al.. Obes Res Clin Pract 2023 · PMID 37573229 · DOI 10.1016/j.orcp.2023.07.001
9. Infant antibiotic exposures and early-life body mass.. Trasande L et al.. Int J Obes (Lond) 2013 · PMID 22907693 · DOI 10.1038/ijo.2012.132
10. The impact of antibiotics on growth in children in low and middle income countries: systematic review and meta-analysis of randomised controlled trials.. Gough EK et al.. BMJ 2014 · PMID 24735883 · DOI 10.1136/bmj.g2267