Intermittent fasting—tech gurus like Twitter CEO Jack Dorsey swear by it, and celebrities like Hugh Jackman said it helped them build muscle mass. It’s one of the most popular wellness trends of the moment, but not everyone is convinced. Some health experts say it can easily become a form of disordered eating.
“Whenever we try to force our bodies to change by means of a restrictive diet, we set off a cascade of protective measures, such as a slowed down metabolism… and a newly ravenous appetite that is difficult to ignore,” says Valery Kallen, a New York-based registered dietitian and certified intuitive eating counselor. “All of a sudden, someone with a previously healthy relationship with food can find themselves at war with their hunger and fullness cues, and obsessively thinking about food all day long,” she adds.
What is Intermittent Fasting?
Obsessively thinking about food isn’t healthy for anyone, but intermittent fasting (IF) promotes knowing when you can and cannot eat. IF is when you eat during a small window of time each day, and then fast for the rest. There are different methods, but one of the most popular is the 16/8 method. This is when you restrict your eating to a daily eight-hour window, then fast for the other 16 hours (typically when you sleep and wake).
IF is touted as a way to quickly burn fat and lose weight, while also promoting mental clarity and boosting energy. But, Kallen says that there’s no strong long-term studies to support most of these claims. She also points out that much of the research done on fasting has been conducted on rodents—not humans.
“Of course, if intermittent fasting produces a caloric deficit (just by the nature of people having less time in the day to consume food), people may experience temporary weight loss,” she says. “However, like all diets, it is only a matter of time before their body slows down their metabolism and increases their hunger signals to adjust for the decrease in energy intake, leading to weight regain.”
How Intermittent Fasting Can Affect Your Well-being
Megan Bruneau, a New York-based registered clinical counselor who specializes in mental health and eating disorders, echoes Kallen’s stance. She says that when we severely restrict our food intake, or don’t eat even when we’re hungry, our body believes food is scarce. When this happens, not only does our metabolism slow, but our hormones can get out of whack, too. And, in extreme cases for women, periods can stop. (Amenorrhea is the absence of menstruation, which can be caused by low body weight or excessive exercise.)
“The hormone that regulates appetite is dramatically affected, and so that really throws off our ability to feel full and pay attention to our hunger cues,” Bruneau says. What’s more, Kallen says that IF can lead to dangerous drops in blood sugar, which can make you feel dizzy or lightheaded. This can affect one’s mentality and well-being, as too low blood sugar can affect concentration and cause headaches.
The Difference Between a Diet and an Eating Disorder
We also need to pay attention to the effects that intermittent fasting can have on our relationship with food. Kallen says that when we see food as something we need to control, it can go from being pleasurable and nourishing to something that causes stress. “In my opinion, a form of eating becomes disordered when it starts to negatively impact a person’s life, either physically, emotionally, or both,” Kallen explains.
She says this can come in various forms including obsessing over food, feeling guilt or shame around eating, or binge eating. Kallen says that those who partake in IF are at risk since research shows restricting food intake can cause disordered eating patterns to emerge. “Furthermore, about 20 to 25 percent of dieters are at risk for developing a full-blown eating disorder, according to the National Eating Disorders Association,” she adds.
If you are struggling with an eating disorder or a form of disordered eating, it’s important to talk to your healthcare provider. They can find you the right support.
How to Eat in a Way That’s Best for Your Health
Bruneau says that if someone wants to eat well or engage in healthier lifestyle habits, intuitive eating is key. Intuitive or mindful eating is when you listen to your hunger cues, stop when full, and nourish your body in the way it needs. This means that if you’re really craving a piece of birthday cake, have it. When you want vegetables, enjoy them just as much.
Bruneau says extreme dieting rarely works, and people often end up putting back on the weight they lost—or gaining more altogether. Intuitive eating, on the other hand, is not a short-term weight-loss solution; it’s a way of life.
“Intuitive eating is definitely at the opposite end of the spectrum, because it allows you to work with your body, not against it like intermittent fasting suggests,” Kallen adds.
While intermittent fasting won’t necessarily develop into an eating disorder for everyone, it’s important to be mindful of the way food restriction makes you feel. If you are suffering through fasting periods and are dizzy and cranky, it’s a good sign that IF is not for you.
Our bodies view food as fuel, and it’s hard to run on empty. “If you listen to your body, you will find that the body prefers to take in energy regularly throughout the day, roughly every three to four hours,” Kallen says. “And you tend to feel better physically—as well as mentally—when you are listening to your body,” she concludes.