what is intermittent fasting heart disease? Intermittent fasting has grown in popularity as a weight-loss tool. Photo: Getty Images. Intermittent fasting devotees who follow a strict 8-hour eating window and fast for the other 16 hours in the day may be at a 91% increased risk of death from cardiovascular disease, preliminary research from a new study says. There’s no shortage of hype about intermittent fasting (IF) in the media. The list of supposed benefits ranges from weight loss to improved mental clarity to decreased inflammation and reduced cancer risk. But what is IF, and is it as beneficial as people claim? And more importantly, is IF safe for you? In this eBook, Anticancer Lifestyle Program Registered Dietitian Crystal Pace and Oncology Registered Dietitian Taylor Scialo will cover the following: The different styles of intermittent fasting, and how IF works Whether IF is effective for weight loss, general health, cancer prevention, or lowering side effects of cancer treatment The risks and limitations of IF The news is everywhere in my social news feeds this morning: A popular fad diet is apparently lethal, scientific research says. Specifically, a study found that caloric restriction, also known as intermittent fasting, has a 91% higher risk of death due to cardiovascular disease. Except scientific research doesn’t say that — and not only should you not be worried about this study, you shouldn’t be wasting brain glucose thinking about it. Even including that 91% number, which you’ll remember, caused me pain, because I don’t think this result should be remembered. The study is a type of nutritional research that is notoriously weak, and right now it’s only available as a press release. It’s not clear from the many, many news articles on the study whether reporters actually viewed the data that will be presented at an upcoming research meeting held by the American Heart Association. So how am I, a science journalist, confidently dismissing this research? It’s based on observational research, and one lesson from more than 20 years of reporting on health and medicine is that one should be very skeptical of observational research, especially when it is about nutrition. What to consider before starting a fasting regimen Western-style diet often leads to food overconsumption, which triggers the development of comorbidities, such as obesity, insulin resistance, hypercholesterolemia, hypertriglyceridemia, type 2 diabetes, and heart failure (HF). Several studies suggest that intermittent fasting (IF) protects against the development of those morbidities. This study presents evidence of the beneficial effects of IF on HF. Based on the current evidence, we discuss the potential molecular mechanisms by which IF works and where liver ketone bodies (KBs) play important roles. There is evidence that IF promotes a metabolic switch in highly metabolic organs, such as the heart, which increases the use of KBs during fasting. However, besides their role as energy substrates, KBs participate in the signaling pathways that control the expression of genes involved in oxidative stress protection and metabolism. Several molecular factors, such as adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferatoractivated receptor, fibroblast growth factor 21 (FGF21), sirtuins, and nuclear factor erythroid 2-related factor 2 (Nrf2) are involved. Furthermore, IF appears to maintain circadian rhythm, which is essential for highly metabolically active organs. Finally, we highlight the important research topics that need to be pursued to improve current knowledge and strengthen the potential of IF as a preventive and therapeutic approach to HF. Keywords: Caloric restriction; cardiovascular diseases; insulin resistance; intermittent fasting; ketosis; metabolic syndrome; obesity; oxidative stress.In this case, researchers used a really useful research tool, the National Health and Nutrition Examination Survey (NHANES), a survey given to 5,000 people a year about eating and dietary habits, as a starting point. These data were linked by the researchers to a separate database of deaths. Both the survey and the database of deaths are administered by the Centers for Disease Control and Prevention. Such databases allow researchers to quickly check to see if dietary choices seem to be associated with health problems. That’s great, because they can help scientists set the direction of more rigorous research that could take years. But the answers that come from doing that are not necessarily reliable. Part of the problem, the easy-to-understand part, is that people answering surveys are not always entirely honest. More than that, especially with food, we often misremember what we’ve eaten and how much. For instance, we might think we followed our diet and totally forget when we slipped up. But the bigger problem is that the people who choose to be on a diet, or those who stay on it, might be fundamentally different from those who don’t in ways that we cannot measure. Perhaps people go on time-restricted diets because they are worried about their health. Perhaps the people who stay on such diets have bodies that work differently than those who can’t fast that long. Perhaps, for whatever reason, the people who were on the diet were different from those who were not simply by random chance. Researchers try to counteract these possibilities by “controlling for” the risk factors they know, like body weight and biological sex or gender or age. But the problem is that researchers can only control for the factors they can identify.