New Study on Intermittent Fasting

New Study on Intermittent Fasting

A new intermittent fasting study presented at the American Heart Association’s Epidemiology and Prevention meeting in Chicago in March of 2024 is currently making headlines. The study finds that a less than eight-hour time-restricted eating window was linked to a 91% higher risk of death from cardiovascular disease as compared to people who ate across a 12 to 16 hour time window.

Looking at this press release, there are a few potential reactions to this new study.  For some of us who promote the benefits of eating breakfast and recommend against intermittent fasting as a general eating pattern, this latest data is cause for gloating.

On the other hand, there are those who completely dismiss this new research as preliminary, flawed, and irrelevant. Why are people dismissing this research? First off, this wasn’t a study published in a peer-reviewed journal, at least not yet. It was an abstract presented at the American Heart Association’s Epidemiology and Prevention meeting. Keep in mind, sharing data in this manner is a normal part of the research process. Typically projects take a long time from conceptualization to publication. As a researcher who is collecting and analyzing data, there are times when your results can be really fascinating and you want to share with others. Presenting preliminary results at a conference is a great way to get peer feedback on your overall project and can help steer the direction of the remaining experiments but it’s important to note that this information has not yet undergone the rigors of peer review. What does this mean? There’s almost certainly more data analysis that needs to be completed, especially modeling to control for different sorts of demographics and socioeconomic factors, and there could be some more supporting experiments that need to be conducted to look at mechanisms. All that is to say that I wouldn’t be surprised if the 91% statistic quoted in this abstract changes slightly.  What’s also interesting about this study is that the preliminary data showed no change to all cause mortality. It’s a bit strange to have such a large impact to cardiovascular disease and not have that reflected in all cause mortality. The most likely explanation at this point is that they don’t have enough data for statistical significance yet. 

So, why was this study such big news? Aside from the large effect observed, this study was presented at a higher tier meeting, and it analyzes data from the National Health and Nutrition Examination Survey (NHANES).  Even though this data relies on self-reported diet recalls, it is one of the highest quality data sets epidemiologists have. But here’s really why the study is so buzzworthy – it’s not actually a surprise! Studies repeatedly show that regularly eating breakfast reduces the risk of cardiovascular disease and type 2 diabetes through circadian rhythm entrenchment and HPA axis regulation. Most of the studies that have looked at the benefits of intermittent fasting have approached it solely from the perspective of weight loss and any metabolic health benefits are attributable to the weight loss and not the manner of weight loss. And, there are other studies that indicate there may be a health cost to losing weight from intermittent fasting, which is pretty common among weight loss diets. Bottom line, if you love intermittent fasting because it’s the only strategy you have found that works for you for creating calorie restriction or avoiding a caloric excess such that you can better manage your body weight, this study is not at the level of evidence that would be required to motivate change but if you’re looking at this new information from a general health perspective, the study is actually adding to an existing body of scientific literature on the effects of intermittent fasting that gives me pause and reasons not to recommend fasting diets more broadly.

If you’d like to hear my take on this latest study on intermittent fasting linked to an increased risk of cardiovascular death, check out my video. And, if you’d like to know more on my thoughts on this topic in general, check out my post – “Breakfast or Intermittent Fasting?”

@drsarahballantyne

Here’s the press release summary: An analysis of over 20,000 U.S. adults found that people who limited their eating across less than 8 hours per day, a time-restricted eating plan, were more likely to die from cardiovascular disease compared to people who ate across 12-16 hours per day, according to preliminary research presented at the American Heart Association’s Epidemiology and Prevention│Lifestyle and Cardiometabolic Scientific Sessions 2024, March 18- 21, in Chicago. The meeting offers the latest science on population-based health and wellness and implications for lifestyle. #nutrivore #breakfastbenefits #intermittentfasting

♬ original sound – Sarah Ballantyne, PhD

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