SUMMARY!
1) Low carb diets do not hurt the thyroid at all. Low carb diets are superior to induce an endocrine / metabolic milieu permissive of body fat atrophy. When body fat in negative balance occurs, as well as the endocrine status of it, this will lead to physiological lower thyroid activity. It takes very low calorie levels of normal carb diets to equal similar changes in insulin/leptin/body fat growth which are easily acheived with higher calorie intakes of low carb. It is the endocrine changes and body fat growth changes that temporarily decrease theyroid activity. It is entirely reversible upon piling up buttery steaks and avocados.
2) It is generally a good thing that one can eat more food before tipping over into "uh oh fat tissue growing!" so I have no idea why anyone is bitching. Isn't this everything that dieters try to accomplish with their chronic exercising and their fake foods with zero calories?
3) Evidence suggests lower insulin, lower thyroid and lower metabolic rate = anti-aging and prehaps promotes longevity. Far from proven but it does suggest this madness to amp up thyroid maximally may be very misguided, like replacing sat fat with trans fat, a horrible misunderstanding leading to very misguided counterintuitive recommendations.
Quotes:
I've recently witnessed a few unfathomable morons on the internet, such as Matt Stone, arguing that hypermetabolic states protect against disease. Apparently these silly people are confusing cause with effect. Illnesses which result in higher stress responses (CORTISOL) will lead to physiological hypothyroidism, by altering T4 conversion to rT3. This is euthyroid sick syndrome.
Just because sickness causes low thyroid does not mean high thyroid protects against sickness. This is grossly irrational, but then again, it's a Matt Stone theory, what would you expect? Higher thyroid would merely be a marker for not being sick. However, the state of very high thyroid would also be a marker for excessive insulin signalling, the very thing that is known to control lifespan and disease resilience in worms, mammals and even closely related primates.
Hot new info: higher metabolic rates and thyroid is positively associated, and a direct result of the endocrine changes also resulting in body fat growth. Growing fatter amps up thyroid, assuming you are euthyroid in the first place. Big myth on the diet blogosphere that low thyroid causes obesity; nope, obese people are hypermetabolic, it's that whole "bathing in insulin+leptin" thing, that crazy responsive sympathetic nervous system thing.
And also, to restate this ... if cheeseslave and others complaining of low thyroid, were to eat 2500 calories of low carb food, you would also be super duper warm. Carbs totally aren't required. You just need food, enough food calories to shift endocrine system thus metabolism to a fed state. I assure you, 3000 calories of steak + brie cheese + pecans will = SUPER WARM AND ENERGETIC and all of these effects you are irrationally attributing to carbs will magically happen on a diet that contains enough food calories. You just need more of them if you choose to eat low carb. Last time I checked, weren't obesity resistant foods a good thing?
If you are eating moderately low cal of a VLC diet and have lost body fat, why are you surprised that you are cold and your basal body temp is low? I mean, seriously? I just can't get over this.
