Low-Fat Diets Kill?
For years people have been wary of eating saturated fat because they were told it would start to cake onto the insides of their plumbing and make their hearts decide it was time to take them to that better place everyone's always talking about.
But according to a huge new study out of Canada, it's low-fat diets – even just diets low in saturated fat – that are more likely to kill us. The study had another surprise for traditional dietitians, too. It showed that high-carb diets tend to send us to earlier graves, too.
A huge international team of researchers conducted a cohort study of 135,335 individuals between the ages of 35 and 70 in 18 countries. Their dietary intake was recorded using validated food frequency questionnaires with a median follow-up of 7.4 years.
The scientists assessed the associations between consumption of carbs, total fat, and each specific type of fat with cardiovascular disease and mortality from all causes.
Contrary to all popular notions about cardiovascular health, it turned out that those who cut back on fats died sooner than those who ate butter, cheese, and meats.
In fact, low-fat diets increased the risk of early death by almost 25%. Those who ingested lower levels of saturated fats raised their risk of early death by 13% compared to those who ate a lot.
Those who ate the most carbohydrates – particularly refined sugars found in sodas and processed meat – also increased their chances of kicking the Spam bucket earlier by close to 28%.
Conversely, eating lots of fats slashed mortality by 23%.
While low-fat diets put people at increased risk for cardiovascular disease, high-carb diets put them at increased risk for other killers like cancer, dementia, and respiratory disease.
Lead researcher Dr. Mahshid Dehghan spelled it out: "A high carbohydrate diet – greater than 60% of energy – is associated with a higher risk of mortality. Higher intake of fats, including saturated fats, are associated with lower risk of mortality."
A second helping of Aunt Doris' lard loaf, that's what this means to you. Okay, maybe not. All things in moderation still applies.
However, there's plenty of reason to maybe stop being so anal about fat consumption. Most who follow the fitness lifestyle are already on a lower-carb track, but few have had the courage to embrace the higher-fat, particularly saturated fat, track.
It may be time to reevaluate that. It may be time to eat that chicken skin, to enjoy the bacon, chew on that cheese, and maybe not cut the fat off that T-bone.
While the Canadian researchers didn't go so far as to make specific recommendations on fatty acid intake, the following pie chart is a pretty good approximation of how much MUFA, PUFA, and SFA you should be eating. (Keep in mind that the PUFA category contains both omega-6 fatty acids and omega-3 fatty acids.)
As far as macronutrients, the old Barry Sears "Zone Diet" recommendations of 40/30/30 (40% of calories from carbs, 30% from protein, and 30% from fat) is probably pretty close to the mark.
- Dehghan M et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Lancet. 2017 Nov 4;390(10107):2050-2062. PubMed.