7 diet studies reveal not all fats created equal

A low-fat diet is supposed to keep us healthy. Or is it?

Here are some of the main studies that started the high-fat hypothesis and then called it into question.
A subscription is required to access the research in some cases.
  • Ancel Keys launched his landmark Seven Countries Study(external link) in 1958. It showed correlations between dietary fat and heart disease.
  • Large, cohort studies at Harvard in women(external link) in 1997 and men(external link) in 1996 looked at diets and suggested total fat was not associated with heart disease — but all fats were not created equal. It was suggested that saturated fat was probably harmful and polyunsaturated fat from vegetable oil or fish oil were likely protective.
  • In 1997, the DASH trial(external link) of a higher carbohydrate, low-saturated fat dietary pattern suggested benefits on blood pressure.
  • The OMNI Heart trial(external link) published in 2005 showed that a low carb, higher monounsaturated fat version of the DASH diet from eating olive oil and nuts for example might be even better.
  • The 2013 PREDIMED study(external link) in Spain showed that a Mediterranean diet rich in monounsaturated fat reduced cardiovascular disease risk by 30 per cent after about five years of followup compared with a control diet that advised reduced dietary fat.
  • Jakobsen's cohort study(external link) on replacing saturated fat with "high" glycemic index carbohydrates raised the risk of heart disease by 33 per cent.