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Another Reason to Beware of Alarming Catchy Research Headlines!!!

Can Intermittent Fasting Really Kill Me?

If you follow the news on health trends, you'll have seen reports of a new study on #intermittentfasting. If you google intermittent fasting and cardiovascular mortality, you will get many hits and a large number of articles summarizing the research. (But look everywhere for the actual research, and you won't find it, because it hasn't been published yet!!! More on that below).


The headlines are alarmist: "Intermittent fasting increases the risk of cardiovascular mortality by 91%"!!! etc. etc.


Some of you may know, research headlines are a big beef of mine! And I am not the only one with reservations about this study's findings and the way it was publicized.


Now, I am not for or against intermittent fasting. What I believe or adhere to or my personal experience is irrelevant. But there are several reasons why this research should not be relied on, and why its dissemination is completely inappropriate. Although it's understandable why it made headlines the way it did, since we live in a fat-phobic culture, and intermittent fasting is a hot trend these days, with doctors and other health professionals touting it as a weight loss cure-all for the "obesity epidemic".


There are 5 red flags with this research and headlines:

  1. When I read the article, the first thing I noticed was that these results have not been peer-reviewed or published yet! These results should not be allowed to be publicized this way. The peer-review process is a requirement of publication (in reputable journals anyway) that ensures the quality of research, and that the methods and results seem repeatable.

  2. There is already a modest and growing body of evidence that points to intermittent fasting being beneficial for many people for several health outcomes (e.g. insulin sensitivity, lipid profile, visceral fat loss, non-alcoholic liver disease). Now we have 1 single study that casts doubt on that (that's unpublished and not peer-reviewed). Should that one unpublished, non-reviewed study really undo the hundreds of other studies that show different outcomes?

  3. This may be the first study looking at long-term outcomes, whereas studies typically look at a few weeks up to a year. This is a classic example of the short-long term risk-benefit ratio that most healthcare practitioners have to deal with on a day to day basis with their patients, and choices that even we normal people make every day: Immediate gratification (i.e. symptom relief, quick weight loss, emotional eating, etc.) vs long-term health (root cause medicine, sustainable optimal weight, longevity, etc.). Should we let the potential long-term risks outweigh the short-term benefits especially if we engage in it only for a short-while? Another classic example of this was the WHI study looking at the long-term impact of menopause hormone therapy on breast cancer and cardiovascular outcomes. Short-term results are great at reducing menopause symptoms like hot flushes and improving sleep, but the study was ended early because it seemed to point to an increased breast cancer and cardiovascular risk in the study population. Later analyses confirmed that initial results were not as bad as they thought, but the headlines were too hasty and the damage was done. It's taken 2 decades for that damage to start to be repaired.

  4. Many observational studies fail to control for other factors than the intervention in question, so it's impossible to infer causality. For example, this study defined someone doing "intermittent fasting" in an 8-hour time-restricted eating window on the basis of a 2-day food diary at the beginning of the study - and then their health outcomes were followed for several years (but not their diet). We know nothing about how frequently they ate in this manner, what they ate, how much they ate, how much they exercised, other medications or chronic health conditions they had, their stress, sleep habits, smoking and alcohol habits, etc. So was it the intermittent fasting, or was it any of these other factors that led to higher cardiovascular mortality? Was it higher cardiovascular risk that led them to choose this way of eating in the first place? Impossible to know.

  5. Generalized results like this are rarely true for everyone. What science is uncovering more and more are vastly different responses based on one's gender, race, age, socio-economic status, beliefs, adverse childhood events, pre-existing conditions, etc. Intermittent fasting and the keto diet have mostly been studied in men. Very few studies have separated out the results based on gender, or only been done on women specifically. Anecdotal evidence and many clinical experts seem to suggest that these studies don't work as well in women and can cause long-term health issues. There have not been studies done on the impact of race either, yet we know that different racial groups have different health and disease profiles.



How Should You Weigh the Risks and Benefits of Intermittent Fasting for YOU?

And as I mentioned in my previous article, you have to weigh the risks and benefits in light of what is most important to you, in an intelligent, comparable manner. What I demonstrated last week was that it's helpful to compare different risks and benefits side by side, like how much cardiovascular vs cancer vs osteoporosis risk/benefit.


In this case, intermittent fasting is one tool among many that has become popularized mainly for changing body composition (specifically visceral fat loss), and by extension comorbid conditions like diabetes and cardiovascular health. But other day to day considerations are equally important, such as, if you're a very active person or are an athlete, intermittent fasting or fasting-mimicking diets like the keto diet may not work well for you especially if you're a woman (although the studies are limited, and with mixed results, here and here). Some studies show that the timing of meals in relation to exercise or sports activity may be more important than overall eating time window.


So, at the end of the day, you have to weigh what is most important to you: fat loss, muscle gain, athletic performance, or long-term health, and consider what you are already doing to achieve that goal. If you're already exercising and eating healthy, then chances are that intermittent fasting won't add that much benefit and may actually be too much and hamper your results in the long-run. On the other hand, if you're not exercising very much, and maybe have a tendency to overeat especially in the evening, then eating in a smaller time window may be helpful. Also you may want to consider doing it sometimes but not all the time since the body adapts to everything to optimize its energy efficiency. So changing it up is a good thing.


**You should also know that if studies of intermittent fasting haven't been done in women much, you can be sure even less is known on the impact for perimenopausal or postmenopausal women. And with a lot more factors impacting our health at this time, you may want to be cautious before exploring a dietary habit that may have a significant impact on your health. I would recommend only trying it under the guidance of a health professional, preferably one that has experience with IF, and who is knowledgeable and experienced in women's hormones. On the other hand, trying a very short fast to start is probably safe, but go slowly and note your symptoms: like a 12-hr fast to start (e.g. 7pm to 7am), then a 14-hr fast (e.g. 7pm to 9am), but be careful beyond that.


As always, hope this is helpful!


If you're interested in becoming a more intelligent and discerning health research information consumer consider signing up for my 2 upcoming workshops:


- Advocating for Your Health Midlife, at PranaShanti Yoga Centre, Sunday April 14, 1:30-3:30pm. Sign up: http://tinyurl.com/4etdv4w4




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