Research

Hormonal

Activation of the nuclear receptor CAR during caloric restriction lowers thyroid hormone levels (T3/T4), which serves as a homeostatic mechanism to resist weight loss; conversely, inhibiting CAR uncouples metabolic rate from food intake, resulting in significantly greater weight loss during caloric restriction.

When you restrict calories, your body defends its weight by lowering thyroid hormones, slowing your metabolism. This is a biological survival mechanism, not a personal failure. Understanding this 'homeostatic resistance' explains why weight loss often plateaus during dieting. Future therapies targeting this pathway (like CAR inverse agonists) may help overcome this natural barrier to fat loss.

GoodSupportsHIGH confidence
Thus, CAR participates in the molecular mechanisms contributing to homeostatic resistance to weight loss. These data imply that CAR represents a novel therapeutic target to uncouple metabolic rate from food intake... Indeed, when Car(-/-) animals were placed on a 40% caloric restriction diet for 12 weeks, Car(-/-) animals lost over twice as much weight as their wild-type littermates.
Jodi M. Maglich et al. · Journal of Biological Chemistry · 2004

Why this rating

High-quality mechanistic evidence using genetically modified (knockout) mice and specific pharmacological agonists, though limited to animal models.

Source

The Nuclear Receptor CAR Is a Regulator of Thyroid Hormone Metabolism during Caloric Restriction

Jodi M. Maglich et al. · Journal of Biological Chemistry · 2004

DOI 10.1074/jbc.m313601200

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DOI resolved against Crossref · corpus check 2026-06-10

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