Myth
Every myth-vs-fact entry verdicted “Myth” so far.
The claim
“Taking a daily multivitamin prevents heart disease and cancer”
The largest trial found no cardiovascular benefit and only a modest cancer-incidence reduction in one group — a major guidelines review calls the evidence insufficient overall.
The claim
“Coffee dehydrates you”
At normal intake, coffee's mild diuretic effect is offset by its own fluid volume — a controlled trial found no hydration difference between coffee and water drinkers.
The claim
“Eating fat makes you fat”
Metabolic-ward trials find low-fat and low-carb diets produce similar fat loss at matched calories — fat isn't uniquely fattening compared to other calories.
The claim
“You can't build muscle after age 30”
Resistance training builds meaningful muscle mass and strength well into older age — the rate slows somewhat, but the capacity doesn't disappear at 30.
The claim
“You need to eat protein within 30 minutes of finishing a workout or you'll lose your gains”
The 'anabolic window' is real but far wider than 30 minutes — total daily protein intake matters far more than post-workout timing.