Major dietary study makes the case for fat
A large Canadian study has found that contrary to popular belief, a diet that contains a moderate amount of fat is linked to a reduced risk of premature death compared to the much-touted low-fat diet. The study by researchers at McMaster University in Hamilton, Ont., also found that eating a high-carbohydrate diet is associated with an increased risk of dying early.
WHO TOOK PART
The information is from the Prospective Urban Rural Epidemiology (PURE) study, which followed more than 135,000 people from 18 low-income, middle-income and high-income countries. The study asked people about their diet and followed them for an average of 7½ years.
MAIN FINDINGS
A diet that includes a moderate intake of fat and fruits and vegetables, and avoidance of high carbohydrates, is associated with lower risk of death. “To be specific about moderate, the lowest risk of death was in those people who consume three to four servings (or a total of 375 to 500 grams) of fruits, vegetables and legumes a day, with little additional benefit from more,” said a release from the university.
As well, contrary to popular belief, consuming a higher amount of fat (about 35 per cent of energy) is associated with a lower risk of death compared to lower intakes. However, a diet high in carbohydrates (of more than 60 per cent of energy) is related to higher mortality, although not with the risk of cardiovascular disease.
TYPES OF FAT
The research on dietary fats found that they are not associated with major cardiovascular disease, but higher fat consumption was associated with lower mortality; this was seen for all major types of fats (saturated fats, polyunsaturated fats and mono unsaturated fats), with saturated fats being associated with lower stroke risk, said Mahshid Dehghan, the lead author for the study and an investigator at the Population Health Research Institute (PHRI) of McMaster University.
Dehghan pointed out that dietary guidelines have focused for decades on reducing total fat to below 30 per cent of daily caloric intake and saturated fat to below 10 per cent of caloric intake. This is based on the idea that reducing saturated fat should reduce the risk of cardiovascular disease, but did not take into account how saturated fat is replaced in the diet.
FAT VS. CARBS
“A decrease in fat intake automatically led to an increase in carbohydrate consumption and our findings may explain why certain populations such as South Asians, who do not consume much fat but consume a lot of carbohydrates, have higher mortality rates,” says Dehghan.
FRUIT
The study found current fruit, vegetable and legume intake globally is between three to four servings per day. “Our study found the lowest risk of death in those who consumed three to four servings or the equivalent to 375 to 500 grams of fruits, vegetables and legumes per day, with little additional benefit for intake beyond that range,” said Victoria Miller, a McMaster doctoral student and lead author of the paper. “Additionally, fruit intake was more strongly associated with benefit than vegetables.”
LEGUMES
Legumes include beans, black beans, lentils, peas, chickpeas and black-eyed peas and are frequently eaten as an alternative to meat or some grains and starches such as pasta and white bread. “Legumes are commonly consumed by many populations in South Asia, Africa and Latin America. Eating even one serving per day decreases the risk of cardiovascular disease and death. Legumes are not commonly consumed outside these geographic regions, so increased consumption among populations in Europe or North America may be favourable,” said Miller.
MODERATION
“Moderation in most aspects of diet is to be preferred, as opposed to very low or very high intakes of most nutrients,” said Salim Yusuf, the director of the PHRI.