If you’re eating trans fats, then stop; if you’re eating saturated fats—which come from meat, butter and lard—then eat less, and add more unsaturated fats to your diet, say researchers from Harvard T H Chan School of Public Health.
For every extra 2 per cent of trans fats we eat, we increase our risk of a premature death by 16 per cent, they estimate, while eating a diet rich in unsaturated fats will increase our chances of living longer by 19 per cent.
With all the contradictory health advice about good and bad fats, the researchers say their advice is about as definitive as we can get.
They tracked the health and diet of 126,233 health professionals, who completed a survey every two to four years for 32 years. During the study, 33,304 participants died, and their diets—and the type of fats they ate—were compared to those who were still living.
Although the trans fats were the deadliest, saturated fats also had an impact on longevity; for every additional five per cent of fats people ate, their mortality risk increased by 8 per cent. Switching from saturated fats to carbohydrates had a minimal positive impact on health, and replacing all fats with carbohydrates ‘modestly’ increased the mortality risk, mainly because carbohydrates in the US are high in refined starch and sugar, the researchers said.