The Claim

Inadequately controlled trials with significant confounding factors, such as differential trans fat intake or multifactorial interventions, demonstrated a false reduction in total coronary heart disease events (relative risk = 0.60, 95% confidence interval 0.46–0.79) when saturated fat was replaced with mostly n-6 polyunsaturated fat, whereas better-controlled trials did not show this effect.

Source: The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
39score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

Some messy studies made it look like swapping certain fats in your diet lowers heart disease risk, but when scientists did better studies, they found that wasn't really true.

See the scientific wording

Inadequately controlled trials, which had significant confounding factors like differential trans fat intake or multifactorial interventions, showed a false reduction in total coronary heart disease events (RR = 0.60, CI 0.46–0.79) when saturated fat was replaced with mostly n-6 polyunsaturated fat, but this effect was not present in better-controlled trials.

What the research says

1 study
  1. Study: The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials

    The study looked at the same diet change as the claim and found that when studies were done carefully, swapping fats didn't reduce heart disease, but messy studies made it seem like it did—just like the claim said.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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