This past week, the American Heart Association solidified its reputation (ref, ref) as being incapable of recognizing quality science. They released a poster session on their website titled “Time-restricted eating may raise cardiovascular death risk in the long term”.
This study basically involved the researchers doing some data mining to make a bold claim that an eating window of less than 8 hours based on two (2) dietary recall days was associated with increased risk of death from cardiovascular disease, but not all-cause mortality.
Why is this study meaningless?
This report comes from a retrospective observational study, which means that they just analyzed a pre-existing database of information to test a hypothesis. It is purely observational, meaning that there was no intervention being tested. This format means that it provides among the lowest quality evidence available. If a researcher has a bias, there’s plenty of ways
to manipulate the data to support that stance.
The database they used is the National Health and Nutrition Examination Survey (NHANES) in 2003-2018. This database was generated from participants filling out Food Frequency Questionnaires (FFQ), a tool with questionable validity. The FFQ requires people to estimate their eating patterns during the previous 12 months by selecting from multiple-choice answer options. FFQs are subject to significant bias and lack validity as a tool to reflect long-term eating habits, especially when the recall period exceeds 24 hours. Recall of eating habits is profoundly inaccurate and unreliable, not to mention that there is significant variation day-to-day.
Two days. They used the average eating duration of only 2 recall days to define the typical eating duration for each individual. Thus, the researchers assumed that these 2 isolated recall days represented the eating habits of these individuals for the entire 8-year follow-up period.
Baseline characteristics may have been a significant factor, as the group with the eating window less than 8 hours also has higher BMI compared to the other groups and also a higher rate of smoking.
Because it was just a poster session, the full publication is not available, but that didn’t stop the AHA from making this bold claim that was clearly going to generate a lot of buzz in the nutrition world. They clearly wanted to put a message out there that calls into question the practice of intermittent fasting.
Summary
The AHA’s decision to publish this press release should make us question their commitment to quality science. In their article, they even refer to the research as “compelling”, when, in fact, that couldn’t be further from the truth. Epidemiological studies like this are the lowest quality evidence, but the media loves to put a sensational spin on anything that’ll get attention, similar to this study.
This low-quality “research” should not change anyone’s approach to their health.
