The evidence
already exists.

Sugar makes children hyperactive.

Double-blind trials find no effect. Parents rated children as hyper when told they'd had sugar, even when they hadn't.

You must drink eight glasses of water a day.

No evidence base has ever been found for the figure. Needs vary, and roughly a fifth of intake comes from food.

Cracking your knuckles causes arthritis.

The sound is gas released in the joint. Studies comparing crackers and non-crackers find no difference in arthritis.

We only use ten percent of our brains.

Brain imaging shows activity across virtually the whole brain over a day. No dormant ninety percent exists.

Reading in dim light damages your eyes.

Low light causes temporary strain and fatigue. There is no evidence of lasting damage to eyesight.

Shaving makes hair grow back thicker.

Shaving cuts the shaft at its widest point, so regrowth feels coarse. Thickness and rate are unchanged.

Vitamin C prevents colds.

Regular supplementation does not reduce how often adults catch colds. It slightly shortens how long one lasts.

Detox teas flush toxins from your body.

Your liver and kidneys do this continuously. No tea has been shown to remove any named toxin.

Eating after eight makes you gain weight.

Total intake over time drives weight, not the clock. Late eating matters only if it adds calories.

You lose most of your body heat through your head.

Heat is lost roughly in proportion to exposed surface area. The head is about ten percent of it.

Cold weather gives you a cold.

Colds are caused by viruses. Winter spreads them because people gather indoors, not because of temperature.

Coffee stunts your growth.

No study has linked caffeine to reduced height. The claim traces back to early advertising, not evidence.

Microwaves destroy the nutrients in food.

All cooking affects nutrients. Microwaving often preserves more, because it is fast and uses little water.

You need to sweat to burn fat.

Sweat is temperature regulation. You can burn fat without sweating and sweat heavily without burning much.

Carbs at night turn straight into fat.

Your body does not track the time. Overall energy balance determines fat storage, not meal timing.

An egg a day will raise your cholesterol.

Dietary cholesterol has a modest effect on blood cholesterol for most people. Guidelines dropped the strict limit.

Gluten is bad for everyone.

Gluten is a problem for coeliac disease and genuine sensitivity. For everyone else there is no demonstrated harm.

You must stretch before exercising.

Static stretching before activity does not prevent injury and can briefly reduce power. Warm up instead.

Brown sugar is healthier than white.

Brown sugar is white sugar with molasses. The mineral difference is far too small to matter.

Wet hair in the cold makes you ill.

Illness requires a virus. Being cold and damp is uncomfortable but does not create an infection.

Your metabolism is fixed after thirty.

Metabolic rate stays broadly stable from twenty to sixty, then declines. Muscle loss explains most of the change.

Deodorant causes cancer.

Large studies have found no link between antiperspirant use and breast cancer risk.