The Claim
During 7 days of 240 kcal/day caloric restriction in obese adults, serum total T4 and plasma pool remain unchanged, while the production rate and metabolic clearance rate of T4 are significantly reduced, and free T4 increases despite diminished tissue uptake.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In obese adults consuming 240 kcal per day for 7 days, total thyroid hormone levels in the blood stay the same, but the rate at which the hormone is made and cleared decreases, while the unbound form of the hormone increases even though less of it enters tissues.
See the scientific wording
During 7 days of 240 kcal/day caloric restriction in obese adults, serum total T4 and plasma pool remain unchanged, but production rate and metabolic clearance rate of T4 are significantly reduced, while free T4 increases despite diminished tissue uptake.
When calorie intake drops sharply, the transporters that move thyroid hormone from the blood into body tissues slow down. This causes more hormone to stay in the blood as free T4, even though the body is making and clearing less of it overall. Because the hormone cannot enter tissues efficiently, cells receive less of it despite higher levels in the blood.
What the research says
1 studyStudy: Effects of caloric deprivation on thyroid hormone tissue uptake and generation of low-T3 syndrome.
When obese people eat only 240 calories a day for a week, their body makes and clears less thyroid hormone, but more of the active form stays in the blood—yet less of it gets into tissues. The study proves this exact thing happened.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.