Intermittent fasting is an eating pattern in which you limit your intake of food for a certain period of time every day, creating a consistent pattern of fasting and eating. Someone following an intermittent fasting regimen might, for example, follow a 16-hour fasting period with an 8-hour eating window.
Side effects of intermittent fasting can include food cravings, constipation, irritability, headaches, binge eating, and rapid gain weight. “I actually liked it at first! It didn’t feel like a real ‘diet’ because I got to eat anything I wanted. But as time went by, it didn’t have any effect on me. It only made me more hyper-focus on food,” said Ellen Setiawan, a University of California, San Diego graduate who is passionate about fitness and health. But research done by the University of Illinois Chicago found that intermittent fasting can help some people lose weight. In addition, intermittent fasting has been shown to improve high blood pressure, cognitive function, cardiovascular disease, inflammation, and insulin resistance and has been linked to improving heart disease and many types of cancers.
Intermittent fasting is safe for many people but not for everyone. People who have eating disorders, advanced diabetes, kidney stones, gastroesophageal reflux, and pregnant and breastfeeding women should not try this diet. Others who could attempt it safely may simply find it ineffective.
“It wasn’t good,” said Araishaa Ajay, a student at Pasadena City College who tried the eating pattern for two weeks. “I usually can’t stick to diets, so I thought intermittent fasting would be good, but it wasn’t good for me and it was really difficult to stick to. It made me want to eat more than usual.”
Although studies have proven temporary side effects of intermittent fasting, no actual long-term data on humans is available on the impact of this diet. Data that showed beneficial long-term effects were mostly from preclinical studies on animals.
“When an individual dramatically changes the way they eat—and when they go for extensive periods without food—it causes both a physiological response, and a psychological response,” said Alisa Dodds, a registered dietitian nutritionist and a senior lecturer in the Department of Health and Human Sciences at Loyola Marymount University.
The body takes time to adjust during intermittent fasting, so it becomes easy to overeat at the end of a fasting period. This could lead to unhealthy eating patterns like binge-eating disorder. “Big dangers of trying to look at things like intermittent fasting, or any diet that tries to tell you how and when and what to eat, is that it causes you to look externally outside of your body, to tell you when, and how much, when and what to eat,” said Dodds. “Intermittent fasting teaches people to ignore their body signals, ignore their hunger, ignore their fullness, and to ignore what their body’s asking them to do. Being disconnected from your body always has negative consequences, leading to overeating later on.”
It’s important to understand that everybody responds to intermittent fasting differently. So, when starting any new eating plan, understand what is suitable for your body and check with your healthcare provider.
“Give yourself unconditional permission to eat everything, and then you will find that you will crave both cake and brussel sprouts. So listen to your body, and that would be my recommendation,” said Dodds.