It's expected for hypothesis that make up a field to converge over time towards something resembling "truth".
When hypothesis change wildly decade by decade (e.g. in nutrition research) without convergence, you can reason that the system isn't working as intended.
In the nutrition example, I think the lack of progress is due to inadequete data and tooling to tackle such a complex field, as well as the limitations imposed by ethical considerations.
Another issue is research bias due to funding from industry. I don't this should be as much of an issue since the efficacy of scientific methods should be mostly independent of funding source.
When hypothesis change wildly decade by decade (e.g. in nutrition research) without convergence, you can reason that the system isn't working as intended.
In the nutrition example, I think the lack of progress is due to inadequete data and tooling to tackle such a complex field, as well as the limitations imposed by ethical considerations.
Another issue is research bias due to funding from industry. I don't this should be as much of an issue since the efficacy of scientific methods should be mostly independent of funding source.