Browse evidence-based analysis of health-related claims and assertions
Lifting heavier weights makes your fast-twitch muscle fibers grow bigger than lifting lighter weights does.
Causal
Lifting lighter weights with more reps might make your slow-twitch muscles grow bigger than lifting heavier weights with fewer reps.
When you start lifting weights, your muscles build new protein faster in the first week than they do after 10 weeks, even if you keep training.
Descriptive
Lifting weights until you can't do any more reps makes your muscles grow just as much, no matter how heavy or light the weights are.
When young men lift weights to get stronger and build bigger muscles, the claim says that getting stronger doesn't really mean you'll get bigger muscles, and vice versa—they're mostly separate things.
Correlational
When young men lift weights to build muscle, their muscle-building process speeds up at first but slows down after 10 weeks, even if they keep increasing the difficulty.
Quantitative
When healthy young men lift weights until they're too tired to continue, their muscles grow about the same amount in both their arms and legs, no matter how heavy the weights are.
Scientists looked at only 8 small studies about how different weight training affects muscle growth. They found there isn't enough research yet to say for sure which exercises work best for building specific types of muscle fibers.
Scientists aren't sure if lifting more weights always makes muscles grow bigger, because their research shows the results are often unclear and sometimes show no effect at all.
When you lift weights, lighter weights might build more of your slow-twitch muscle fibers, while heavier weights might build more of your fast-twitch muscle fibers, but scientists aren't totally sure yet.
Lifting heavier weights might make your fast-twitch muscle fibers grow more than lighter weights, but the results aren't totally certain.
Lifting lighter weights might make slow-twitch muscle fibers grow more than lifting heavier weights, but scientists aren't totally sure yet because the results aren't clear.
When researchers combined many small studies about salt and stomach changes, they found signs that the smaller studies might have problems or were more likely to be published if they showed certain results. This could make the overall results less reliable.
Eating salt doesn't seem to affect stomach changes differently in various parts of the world or in different types of studies—it's pretty much the same everywhere.
Eating salty foods seems to be more strongly linked to early stomach changes that can lead to cancer than to actual cancer itself, meaning salt might affect cancer risk earlier in the process.
Eating a lot of salt is linked to changes in your stomach lining that might lead to health issues, and many big studies show this connection is real even though the exact strength varies a bit.
Eating more salt is linked to a higher chance of having a stomach condition called gastric intestinal metaplasia, which means your stomach lining changes in a way that might not be healthy.
As people get older, more of them get sick with stomach cancer from eating too much salt. This cancels out some health improvements in certain areas and leads to more years of poor health, even though overall cancer rates are going down.
Men are much more likely than women to die or suffer from stomach cancer due to eating too much salt, with rates over twice as high in 2021.
This is about how eating too much salt can lead to stomach cancer. It says that in East Asia, fewer people are dying from this type of cancer now compared to 30 years ago, and people are also living healthier lives without as much sickness from it.
Areas with higher wealth and development saw much bigger drops in salt-related stomach cancer deaths and health problems from 1990 to 2021 than poorer areas, showing a big gap between rich and poor regions.
Fewer people worldwide are dying or suffering long-term health problems from stomach cancer linked to eating too much salt, with death rates dropping by almost half and overall health impact decreasing by more than half since 1990.
Doing a special warm-up before lifting weights doesn't make you any stronger in chest, leg, or back exercises than just lifting weights normally during full-body workouts.
When experienced male athletes repeated certain tough workouts within two days, it didn't really hurt their training progress because they lifted about the same amount each time.