The Study
The energy savings-oxidative cost trade-off for migratory birds during endurance flight
This study watched two groups of birds fed different fats and saw that the ones with more omega-6 fats used less energy when flying but had more cell damage over time. It shows a link, but we can't say for sure that the fat caused these effects because we don't know if the birds were randomly assigned to groups.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Birds burn fat to fly long distances. What they eat changes the type of fat they store. Some fats give more energy for less effort, but can hurt their bodies over time.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 514 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This is like choosing a fast-burning fuel that helps performance now but wears out the engine faster—useful for migration, but possibly harmful over time.
- 2Birds eating more omega-6 fats used 11% less energy flying for 6 hours.
- 3Their bodies showed more damage later, even if they felt fine right after flying.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
eLife
Year
2020
Authors
S. McWilliams, Barbara J Pierce, Andrea Wittenzellner, Lillie A. Langlois, Sophia Engel, J. Speakman, Olivia Fatica, Kristen J. DeMoranville, W. Goymann, Lisa Trost, Amadeusz Bryła, M. Dzialo, Edyta T. Sadowska, Ulf Bauchinger
Related Content
Claims (5)
Polyunsaturated fats go bad more easily than other fats—both in your pantry and in your body—because of their chemical structure, which can lead to more damage in cells.
Migratory birds burn fat to fly long distances, and when their fat has more omega-6, they use less energy to fly—but it comes at a cost: more cell damage over time. It's like getting better gas mileage in a car that wears out faster.
Birds that have more omega-6 fats in their bodies use about 11% less energy when flying long distances compared to birds with different kinds of fats — at least in starlings tested in labs.
Starlings that have more omega-6 fats in their bodies don’t seem worse off right after long flights, but over time, those fats lead to more cell damage — like a hidden cost that shows up later.
Starlings burn the same amount of energy at rest no matter what kind of fat they eat or whether they’ve been trained to fly — the energy savings from certain fats only kick in when they’re actually flying.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.