Intermittent fasting is making big waves in the wellness world again, but not with great news.
The American Heart Association this week published results of a study that found that people who restricted their eating to fewer than 8 hours per day have a 91% increased risk of dying from cardiovascular disease compared to people who stretch out their eating hours.
The results of the survey, which included information from more than 20,000 US adults (414 in the 8-hour eating window group) were presented at the Epidemiology and Prevention, Lifestyle and Cardiometabolic Health conference in Chicago. The study hasn’t yet been peer-reviewed.
There are different types of intermittent fasting; time-restricted eating, which the latest study focused on, is one of them. People may restrict their eating windows from 12 hours down to 6 or fewer, but an 8-hour eating window is common. Intermittent fasting has gained popularity as a potential way to lose weight, lower cholesterol and reduce other risk factors for heart disease. This is one reason headlines on the recent study were so jarring; previous research had suggested an opposite link to heart health, but with shorter-term results.
But the experts we spoke with urged us not to take the results of this study as rule; the senior author of the study also stressed in the AHA post that the association found in this study doesn’t mean intermittent fasting caused cardiovascular death.
For one, the latest research does not account for the reasons people were restricting their eating window in the first place, or other things that may influence their health. These types of “confounding” factors in health make studies on diets, or wellness in general, tricky, according to Dr. Andrew Freeman, a cardiologist with National Jewish Health in Denver.
“People seldom do harmful or even helpful things in isolation,” Freeman said.
People may go for longer periods of time without eating for a variety of reasons, including an erratic work schedule where they may have to get all their food in during a shorter window, they may have disordered eating patterns, they could have a mental health challenge that affects their sleep-wake cycle, and so many more scenarios that would cause someone to report shorter eating windows, but also introduce other factors known to negatively affect cardiovascular health.
Sometimes, people fast for spiritual reasons. Coincidentally, the latest research about time-restricted eating falls as people around the world are observing Ramadan, a holy month of fasting in the Muslim faith.
We may say, then, that the latest research is a catalyst for another conversation on how to find a nutrition plan that works for you and your life, how to tune into your hunger signals and how to practice the best diet for heart health.