In the “Where should my priorities be to improve my health?” article, the following was noted with regards to fat (and carbs):
CARBOHYDRATE AND FAT: INTAKE CAN VARY BASED ON PERSONAL PREFERENCE (E.G., HIGH/LOW FAT OR HIGH/LOW CARB). HOWEVER, DIETARY FAT INTAKE SHOULD BE BIASED TOWARDS UNSATURATED SOURCES (E.G., FISH/PLANT SOURCES), WITH ANIMAL-BASED SATURATED FATS HELD TO APPROXIMATELY 10% OF CALORIES OR LESS. ONE NOTABLE EXCEPTION IS THAT SATURATED FATS FROM DAIRY SOURCES (EXCLUDING BUTTER) APPEAR TO BE HEALTHFUL AS WELL.
If someone has engaged in weight loss and has found success in a low-fat diet (and has sufficient protein, fiber, <10% saturated fat, etc) do you think it is worth it to add in more unsaturated fat sources, such as olive oil or nuts into their diet, in place of carbs? I ask because it was noted in the Nutrition Science, Part IV – Moving Forward: Improving the approach article that “emerging evidence for food-based interventions is encouraging, with the PREDIMED intervention to consume 4-tablespoons extra-virgin olive oil per day, or consumption of 30g nuts per day, leading to a 30% reduction in cardiovascular disease risk over 4.5-years”.
Agree with Jordan that this would depend on what their typical carb sources are and what their blood lipids look like in the context of their overall CV risk.
For a more detailed look, our friends a Sigma put together some good resources on this topic:
Thanks for the links @Austin_Baraki . In those articles, the following was noted:
the most significant impact of diet on blood lipids, and CVD/CHD risk, is the relationship of SFA to PUFA, known as the ‘P:S ratio’. So for example, moving from a P:S ratio of 0.5 to a ratio of 2.0 would impart a strong lipid lowering effect.
and:
The broad category of ‘complex carbohydrates’ was examined in the comprehensive metabolic ward study meta-analysis by Clark et al. The reduction in blood lipids from isocaloric substitution of 10% energy from SFA with complex carbohydrate was found to be 20.07mg/dL (0.52mmol/L). However, the magnitude of lipid-lowering from the same isocaloric replacement of SFA with unsaturated fat (MUFA + PUFA) is three times that of substitution with complex carbohydrates.
and overall:
A number of conclusions can be made, bringing this series and body of evidence together. First, the relationship between SFA and CVD/CHD is most pronounced at high - 16%-24% - levels of dietary intake. Secondly, this relationship is strongly and primarily mediated by the impact of diet on blood lipids. Third, population-wide interventions that are successful in reducing SFA intake are accompanied by a decline in CVD/CHD mortality and events. Fourth, the magnitude of effect is mediated by the nutrient replacing SFA in the diet, with the following hierarchy evident: 1. Polyunsaturated fats (from plant and marine sources);
Monounsaturated fats (from plant sources);
Unrefined, complex/wholegrain carbohydrates.
So, based on that, it looks like if someones SFA intake is relatively high (defined as 16%-24%) then replacing SFA with polyunsaturated fat seems to be the best thing to do, presumably to increase that P:S ratio, with monounsaturated fat and unrefined complex carbs coming in 2nd and 3rd, respectively.
What I am curious is if someone’s SFA is already low–i.e. <=10% of their daily calories–does the importance of the P:S ratio and the hierarchy of substitution sources still hold? I ask because I imagine in some low-fat diets–depending on how “low-fat” is defined–the individual may not be getting very much of either saturated or unsaturated fat, so the P:S ratio may be not very high.
The idea is to reduce saturated fat to < 10% of total daily calories, ideally replacing SFA with PUFA or MUFA. Complex carbs would work too. Would not worry about the ratio at all after this.
We don’t think it matters based on present evidence addressing fat substitution when SFA is < 10%.