that is an impossible standard to apply to diet-based research which is incredibly expensive to otherwise study (e.g, you need a metabolic ward and at that point you'd complain about small N).

We know saturated fat increases LDL, we know LDL contributes to CVD. This is still an area of active research and there are small populations of people that don't accept the consensus but it is still very much best-practice keep your LDL low.