The idea that saturated fat causes heart disease might have started because scientists only shared part of the data — they published results from 7 countries that supported the link, but left out data from 15 others that didn’t show a connection.

Scientists found a link between eating saturated fat and heart disease by leaving out data from different countries that didn't fit their idea.

The Seven Countries Study selectively reported data from only seven of 22 analyzed countries to falsely imply a causal relationship between saturated fat intake and cardiovascular disease, omitting data from 15 countries showing no association.

People say this old study proved that eating fatty foods causes heart disease, but it only picked countries where both fat intake and heart disease were low—and ignored places where people ate lots of fat but still had low heart disease. That makes the conclusion unfair.

A famous old study that tried to link eating butter and meat to heart disease might have gotten it wrong because it picked countries in a biased way and asked people what they ate during times when they were fasting, which doesn’t show their normal eating habits.

Studies that found a link between saturated fat and heart disease are more likely to get published than those that found no link — which might make it look like there’s a connection when there isn’t.