AFAIK (not an expert) there are two common problems with nutritional research
1) Mechanistic data we don't fully understand the implications of.
This basically means we observe mechanisms that we believe ought to have some effect on people, and yet when longitudinal studies are done to measure actual long term effects, they are not statistically significant
2) Confounding factors.
In longitudinal studies, it can be very difficult to fully control for confounding factors, as diets are very complex. Take a hypothetical red meat study, where participants are simply instructed to eat "more red meat". Is a McDonalds burger different than a lean, grassfed steak? That's an easy one to control for, not the best example. But basically exemplifying how there can be a lot of variability within the intervention itself when it comes to nutrition
amanj41|3 years ago
1) Mechanistic data we don't fully understand the implications of.
This basically means we observe mechanisms that we believe ought to have some effect on people, and yet when longitudinal studies are done to measure actual long term effects, they are not statistically significant
2) Confounding factors.
In longitudinal studies, it can be very difficult to fully control for confounding factors, as diets are very complex. Take a hypothetical red meat study, where participants are simply instructed to eat "more red meat". Is a McDonalds burger different than a lean, grassfed steak? That's an easy one to control for, not the best example. But basically exemplifying how there can be a lot of variability within the intervention itself when it comes to nutrition
unknown|3 years ago
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