All the studies were done on men who already had heart problems — we don’t know if the same results would apply to women or people without heart disease.
Scientific Claim
All six randomized trials included in the meta-analysis were conducted exclusively in men, with only one including primary prevention participants, limiting generalizability to women and healthy populations.
Original Statement
“All but one trial exclusively studied secondary prevention participants. ... No women had been studied; no primary prevention study had been undertaken.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
This is a factual description of the study population characteristics, directly stated in the results and discussion. No overinterpretation is present.
Evidence from Studies
Supporting (1)
Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis
All the studies used to make dietary rules were only on men, and most were on men who already had heart disease — only one was on healthy people, and none included women. So the rules might not work for everyone.