Periodic reminder that there are incredibly few universals when it comes to human health.

To illustrate, everyone needs sleep.

Not everyone needs the same amount of sleep. The amount of sleep you need varies by age, whether you're injured, pregnant, ill, hormone levels, seasons, weather, etc.

"People need sleep" is a universal. "People need 8 hours of sleep" is not.

Further examples:

"Everyone needs to eat" is a universal.

"Everyone needs to eat a diet low in sodium, rich in whole grains, with two servings of fruit or veg at every meal" is not.

"Vitamin and mineral supplements are unnecessary" is not a universal.

"Bike riding is good exercise" is not a universal.

"Yoga is a wonderful practice" is not a universal.

"You need to drink 8 glasses of water a day" is not a universal.