We shouldn’t be asking the question, “How do I get a higher metabolism?” We should be asking the question, “How do I improve the quality of my metabolism?” Which is a very different story. Anybody can have a higher metabolism.  You can do it, for instance, with recreational drugs and diet pills, many of which have been taken off the market,. These for the most part, will actually increase the rate of aging and its symptoms, as will many other ways to “raise” metabolism just for the sake of raising it such as the many “thermogenic aids” in “health food” stores.  If you simply seek to increase metabolism, you’re just going to increase the rate of whatever kind metabolism you’ve got going, good or bad. So if you’ve got a less than optimal metabolism, and you just increase the rate of it, you’re just going to increase the damage that it’s doing.  That’s what you see in many, many people. And that’s a major problem.

A related problem is a misunderstanding about how the thyroid, and diet, interact with metabolism.  One of the major issues that one sees in the so-called safe starch debate, is that the advocates of eating more starches often warn that when you don’t eat carbs, you end up with a  lower amount of the thyroid hormone, T3, in the blood, and this is a warning sign of hypothyroidism–meaning too little thyroid function. And that’s just such a wrong way of looking at it. Certainly when you eat a very low-carbohydrate, high-fat diet, the amount of T3 in your blood goes down—but in most cases, even though T3 goes down, your TSH – thyroid stimulating hormone – does not go up.   TSH is a kind of thermostatic regulator.  When the body actually needs more thyroid hormone, TSH generally rises, and pushes the thyroid to make more T3.  When the body is getting enough thyroid, TSH generally stays low.  So if your thyroid hormone levels go down while your TSH also stays in the low to normal ranges, it’s probably not because your thyroid is sick, any more than your pancreas is sick when your insulin level goes down on a very low-carbohydrate diet, and your blood sugars stay low as well.   When insulin levels go down and blood sugar becomes more normal as well, it’s a clue that your cells are finally becoming less insulin resistant and are getting sensitive to a healthy, low level signal of insulin.  In a similar way, a low TSH, coupled with a lower T3 level, is indicative, not of a sick thyroid, but more of proper signaling.  You might say it indicates that your cellular resistance to the signals of thyroid is letting up.  Your cells are getting more sensitive to thyroid signals, and your T3 level is going down precisely because cells can finally hear the signal properly.  So a lower thyroid level, with low- to normal TSH, can indicate that your metabolism is now functioning at a higher-quality level. In other words, you’re getting more bang for each energy buck.

More bang for the buck is also happening, for instance, in calorie-restricted animals who live longer than animals fed a regular amount of calories.  In calorie-restricted animals, researchers generally see a lower free T3.  They also see lower T3 in centenarians, people who live past 100. When you see a lower free T3, it’s really indicative of kind of a longevity phenotype. It’s indicative of what you might even call, non-hibernating hibernation. And one clue that this lower T3 is healthy is that people who have it generally report that they function better.  If it happens to you, on a low-carb diet that you’ve become adapted to over time, you’re not weak. You generally have more energy.

Having your T3 level go lower, in a healthy way, is like being able to turn down the idle of a car when it’s tuned properly, so that at rest it doesn’t have to waste as much energy.  In an efficiently running car, the resting “metabolism” of the car is lower.  And if you want to get power from that car, if you want to accelerate, that’s better too.  When a car is well tuned, it allows for a lower idle speed, and it will actually accelerate faster, and the engine itself certainly will have a much longer lifespan. It’s functioning better.