The Study
The effect of varying carbohydrate content of a very-low-caloric diet on resting metabolic rate and thyroid hormones.
We don't know how the study was done, so we can't say if eating different carbs really changed metabolism. It's like seeing a picture of two things happening together but not knowing if one caused the other.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
When people ate very few calories, eating more or fewer carbs changed their thyroid hormone levels, but didn't change how many calories their body burned at rest.
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 520 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — even if you change carbs, your body still slows down its calorie burning the same amount on a very low-calorie diet.
- 2T3 levels dropped more or less depending on carbs; RMR dropped the same amount either way.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Metabolism: clinical and experimental
Year
1986
Authors
R. Mathieson, J. Walberg, F. Gwazdauskas, D. E. Hinkle, J. Gregg
Related Content
Claims (3)
When thyroid hormone levels are low, the body's metabolic rate decreases, leading to less fat burning, weight gain, constipation, and fatigue.
When people eat a very-low-calorie diet, reducing carbohydrate intake causes a greater drop in the thyroid hormone T3, but the decrease in resting metabolic rate is the same regardless of how much carbohydrate is consumed.
When thyroid hormone levels are low, the body's energy use slows down, leading to less fat burning, increased weight, constipation, and tiredness.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.