Browse evidence-based analysis of health-related claims and assertions
Log in to see full claim details, scientific mechanisms, and cited studies.
Differences in the natural levels of thyroid hormones in the body are associated with changes in how many calories a person burns per day, with the maximum change being 10%.
Over time, changes in body fat mass result from the consistent difference between the amount of energy consumed and the amount of energy expended.
When people return to their previous eating and activity habits after losing weight, their body fat tends to increase back to the level it was before the weight loss.
When a person consistently consumes more energy than they expend, the excess energy is stored as body fat.
Among elite judo athletes, the total amount of resistance training does not reliably determine increases in muscle size or strength; instead, how heavy the weights are and how fatigue is managed...
In elite judo athletes, getting bigger muscles through resistance training does not always result in more force or power per unit of muscle mass, meaning larger muscles do not automatically make...
In elite judo athletes, performing resistance training with different loads or to muscle failure does not change their ability to generate power, as measured by specific force and velocity metrics.
Among elite judo athletes, performing light-weight resistance exercises to muscle failure results in less increase in muscle size and strength compared to using heavier weights to failure or using...
In well-trained male judo athletes, six weeks of resistance training using either heavy weights to failure or light weights without failure increases the size and maximum strength of the elbow flexor...
Tailoring resistance exercise programs to a person's specific muscle endurance capacity, instead of using the same number of repetitions for everyone, may result in more consistent physical...
When people perform the same weightlifting exercise at the same intensity, some can do many repetitions while others can do few, showing that using a fixed number of repetitions for everyone may not...
When people lift light weights (30% of their maximum) either until they can't do another rep or for a set number of reps, the changes in muscle swelling, how hard they feel the workout was, and how...
When lifting weights at 60% of maximum strength until exhaustion, the consistency of how hard the exercise feels and the degree of muscle swelling decreases compared to doing a set number of...
When people lift weights until they can't do another rep at 60% of their maximum strength, the changes in muscle swelling and how hard they feel the exercise is tend to be more consistent between...
When trained men estimate how close they are to muscle failure during weightlifting, their self-reported estimates often do not match measurements of barbell speed, which show they were actually...
For trained men who lift weights for eight weeks, how close they get to muscle failure—whether stopping 1–3 reps short, 4–6 reps short, or going all the way to failure—does not lead to measurable...
In trained men, lifting weights until complete muscle fatigue may lead to more people quitting the program or not following the rules, compared to lifting at a lower intensity.
In trained men, training resistance exercises close to muscle failure does not produce greater increases in muscle thickness of the thigh or chest muscles compared to training further from failure,...
For trained men, lifting weights with some reps left in reserve (4–6 or 1–3 RIR) leads to similar strength gains in bench press and squat as lifting until complete exhaustion, but lifting to failure...
People who regularly lift weights can estimate how many more reps they have left before reaching failure, usually within one rep, making repetitions-in-reserve a practical tool for adjusting workout...
When performing resistance training, training to muscle failure may lead to slightly more growth in the vastus lateralis muscle, while training with 1-2 reps left in reserve may lead to slightly more...
Over eight weeks, lifting weights with a small reserve of repetitions left in the tank produces the same total amount of work and muscle growth as lifting until complete exhaustion, suggesting that...
When people lift weights until they can no longer complete another repetition, they experience more short-term muscle fatigue than when they stop a few reps before failure, as shown by slower...
For people who already train with weights, stopping sets when they have 1 to 2 reps left in the tank leads to about the same increase in quadriceps muscle size after eight weeks as pushing to...