The Claim

Low levels of thyroid hormones reduce metabolic rate, resulting in decreased fat burning, weight gain, constipation, and fatigue.

Source: Ep.15 - Thyroid Health Explained: Reclaiming Vitality with Elle Russ | Baby, Let's Talk! Podcast

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
46score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
3 studies reviewed
In plain English

When thyroid hormone levels are low, the body's metabolic rate decreases, leading to less fat burning, weight gain, constipation, and fatigue.

See the scientific wording

Low levels of thyroid hormones reduce metabolic rate, leading to decreased fat burning, weight gain, constipation, and fatigue.

Why this might work

When thyroid hormone levels drop, the body slows down its energy use by reducing the activity of mitochondria in cells, decreasing heat production, and lowering the drive to move and burn fat. This causes the body to store more fat, feel tired, and slow down digestion.

Verified mechanismbased on 3 studies

What the research says

3 studies

  1. Study: Body weight and waist circumference are differentially associated with the response to L-thyroxine treatment in primary hypothyroidism

    When people have low thyroid hormone, their body slows down and they gain weight; when they take medicine to fix it, they lose weight and feel better. This study shows that fixing low thyroid hormone leads to less belly fat and better cholesterol, which means the body’s metabolism picks up again.

  2. Study: Resting Metabolic Rate, Body Composition and Thyroid Hormones

    When people eat very little, their thyroid hormone levels drop, and their body burns fewer calories at rest — which explains why they might feel tired, gain weight, or have trouble going to the bathroom.

  3. Study: The effect of varying carbohydrate content of a very-low-caloric diet on resting metabolic rate and thyroid hormones.

    When thyroid hormone levels drop, even due to dieting, the body burns fewer calories at rest — which can lead to feeling tired and gaining weight. This study shows that lower thyroid hormone levels go hand-in-hand with a slower metabolism.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 3 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.