One of the things that makes mainstream nutrition hard for me to buy is the evolutionary argument.
How can saturated fats, the main ingredients in breast milk and animal products, be bad for humans (an apex predator)? Was eating animals really giving our hunter gatherer ancestors heart attacks left and right?
Similarly for seed oils, through them we're eating such a ridiculous amounts of PUFA; something that would be quite impossible in the ancestral environment. How can our bodies possibly be adapted to cope with that?
The consequence of this is that none of... (read more)
By what mechanism could natural selection have optimised our diets? Why should we expect long-tenured features of our diet to be necessarily healthy? We have consumed alcohol since long before we were modern humans, as one obvious counter-example to this sort of argument.
3Slapstick
I think there's a few issues with this reasoning.
For one thing, evolution wasn't really optimizing for the health of people around the age where people usually start having heart attacks. There wasn't a lot of selection pressure to make tradeoffs ensuring the health of people 20+ years after sexual maturity.
Another point is that animal sources of food represented a relatively small percentage of what we ate throughout our evolutionary history. We mostly ate plants, things like fruits and tubers. Of the groups who's diets consisted of mostly meat, there is evidence of health issues resulting.
The nutritional profile of breast milk is intended for a human who is growing extremely quickly, not for long term consumption by an adult. Very different nutritional needs.
I believe mainstream nutrition advises against consuming refined oils, including seed oils . I may be missing a point you're making.
6ErickBall
Saturated fats are definitely manageable in small amounts. For most of history, and still in many places today, the biggest concern for an infant was getting sufficient calories, and saturated fat is a great choice for that. When you look at modern hunter-gatherer diets, they contain animal products, but in most cases they do not make up the majority of calories (exceptions usually involve lots of seafood), the meats are wild and therefore fairly lean, and BMI stays generally quite low. Under those conditions, heart disease risk is small and whether it is slightly increased by the saturated fat in one's diet is mostly irrelevant. There is a big difference between chasing down the occasional antelope and pulling up to the drive through for a cheeseburger. So the evolutionary argument really is not strong evidence that saturated fats are harmless.
I agree that the studies we have are mostly inadequate, but I don't think using hunter-gatherer diets as a control would be very useful either. If you change everything at once, you can't isolate specific causal factors. What we really need (but can't have) is a bunch of large scale trials that have many groups with many different interventions and combinations of interventions, and statistical power to distinguish outcomes between each group.
One of the things that makes mainstream nutrition hard for me to buy is the evolutionary argument.
How can saturated fats, the main ingredients in breast milk and animal products, be bad for humans (an apex predator)? Was eating animals really giving our hunter gatherer ancestors heart attacks left and right?
Similarly for seed oils, through them we're eating such a ridiculous amounts of PUFA; something that would be quite impossible in the ancestral environment. How can our bodies possibly be adapted to cope with that?
The consequence of this is that none of... (read more)