Ten adults did the same 14-day diet twice: once on 8.5 hours' sleep, once on 5.5. The scale showed the same loss both times. On short sleep, 55% less of it was fat and 60% more of it was muscle. A separate 80-person trial found sleeping longer cut intake by 270 calories a day, with no change in what people burned.
22 randomised trials say brisk walking takes off about 4.7 lb — and 5.7 lb of fat, because fat-free mass went up at the same time. The famous step target is not a finding: it is the name of a Japanese pedometer sold in 1965.
Studied at up to 30 g a day for five years, in groups from infants to the elderly. The kidney scare has a real source: creatine raises serum creatinine, the marker doctors read as kidney function — while the kidneys' actual filtration rate stays put. The gauge moved, not the engine.
54 randomised trials, resistance training against people doing no exercise at all, nobody dieting: body fat percentage fell 1.46 points (1.08 in the trials that used DXA scans) and fat mass about 1.2 lb. The percentage moved further than the fat did, probably because muscle was going on, and a bathroom scale adds the two together.
Across 21 studies, the people who lifted and did cardio still built a large amount of muscle — less than lifting alone, but nowhere near losing any. The cost is real and it depends on how much you do, and running causes it while cycling mostly doesn't.
Twenty-one trials longer than eight weeks, screened from 23,441 records: a trend toward benefit, and a confidence interval that includes zero. Then the FTC found the marquee study's subjects had been told to diet and exercise — while the press release said they hadn't.
6,421 people across 29 countries, measured by doubly labelled water: energy expenditure is flat from 20 to 60, even during pregnancy. It falls about 0.7% a year after that. The decline is real — it just starts four decades later than everyone thinks.
Fifteen women, a ventilated hood, and 100 g of celery: digesting it cost 13.76 of the 16 calories it delivered. That is 86% — far closer to free than we first said. It is still not negative, and the researchers said so themselves.
Measured against no gum, chewing raises energy expenditure by about 0.06 kcal a minute — roughly a third of an almond per hour. A 201-person trial with 95% adherence chewed 90 minutes a day for eight weeks and lost nothing.
Oxidise 10 kg of fat and 8.4 kg of it is exhaled as carbon dioxide. Eccrine sweat is water, sodium and chloride — lipid is not a meaningful constituent. You cannot sweat out something that is not in the sweat.