03/09/2026
A lot of new clients come to me thinking that they need to drop their calories further and that this is where the answer lies to keep fat loss turned on. In reality most of them actually need their calories increasing. This is the thing that actually sees progress start moving again and fat loss resuming. Sometimes more is actually less when it comes to this. Let me explain on the next slide…
So most of you have heard of your thyroid, the thing people like to use as an excuse for not being able to shift weight etc but let me actually explain how it works, because this is where it clicks. Your thyroid mostly pumps out T4, which is basically a storage version, inactive until your body converts it. An enzyme called 5-prime-deiodinase does that conversion, turning T4 into T3, the active hormone that sets your metabolic rate. That’s the master dial.
Now the clever, annoying bit. Under-eat hard for long enough and your body reads it as famine and turns that enzyme down. So less of your T4 becomes active T3, and more gets shunted into reverse T3, which is inert, it does nothing. On top of that, prolonged under-eating even reduces the number of T3 receptors your cells carry, so the T3 you do have lands softer. Less active hormone, fewer places for it to work.
Why you feel it everywhere: T3 raises your rate by making cells burn more fuel to produce heat, running the sodium-potassium pumps harder in every tissue you own. Turn that dial down and everything downstream slows with it, temperature, energy, recovery, the lot. And the scale is real, prolonged under-eating on its own can pull your metabolic rate down 20 to 30 percent before the T3 drop is even added on top. That’s not a faulty thyroid. That’s a healthy one doing precisely what it evolved to do.
The rate slowing is only half of it. The other half is hormonal, and it’s the part that makes deep dieting feel like a personal failing when it absolutely isn’t.
As you lose weight, ghrelin, your hunger hormone, climbs, and leptin, your fullness hormone, drops. And here’s the kicker most people never hear: those changes don’t reset when you hit your goal, they persist for at least a year after the weight is gone. Lep