The number on the display has a decimal place. In the best direct test, one reading from the worst of three bathroom scales fits a DXA value anywhere across a 23-point span, and even the best scale's band was about 13 points wide.
The main Cochrane review says exercise eases chronic back pain, at moderate certainty, and most clearly in the first few months. For a new episode the answer is different, and which exercise is best is less certain still.
Slowing the rep down is sold as the secret to growth. A 2025 meta-analysis of 14 studies that changed only the tempo found a difference of 0.09 — and it leaned the other way.
A randomised trial measured thigh muscle by MRI before and after. The vegan groups lost muscle and weight, lifting nearly halved the muscle loss, and protein fell even with a dietitian's advice.
One of the few things in the supplement aisle with an umbrella review behind it. Here is the dose, the timing, the size of the effect — and the one thing it is not doing.
Soreness is the most popular progress gauge in the gym, and it is not measuring progress. It tracks muscle damage only loosely, and in the trials that measured growth it did not predict it.
A vest is credited with 1.6 lb of extra fat loss. That figure rests on one eight-week trial, and in it the women who wore only the vest gained fat. The bone claim got its best test during weight loss, in 150 people over a year, and failed it.
Eleven small controlled trials of lion's mane in people. Two beat placebo on a dementia screening test; seven found no difference. The famous 2009 gain shrank once people stopped, and it came largely from a mushroom company's laboratory.
The confident objection is that your gut destroys it. A six-month trial in 54 people says body stores rose by a third. The unanswered question is whether that does anything for you.
A panel convened because nobody could agree what zone 2 was. They agreed on a definition — and then wrote that the adaptations might not be unique to it. Meanwhile the calculators cannot find it on you.