There are so many benefits of intermittent fasting. Yes, it can help you lose weight, but you may also feel more focused and energized, experience less bloating, gain control of your cravings, and more. Like any eating plan, though, it's not one-size-fits-all — and personally, shrinking the window in which I could eat made me pretty miserable. Exhausted and hangry, I eventually went back to eating on a normal schedule. I was curious if my experience is common, though, so I decided to ask the experts. Here are three reasons you may need to quit, according to dietitians and a doctor.
1. You Can't Shake the Side Effects
Intermittent fasting isn't without side effects, including some of the very things it's thought to combat, like low energy levels and poor sleep. I had trouble keeping up with my workouts, couldn't seem to concentrate outside my eating window, and would often wake up hungry during the night. "Your timing of meals might also affect your circadian rhythm," explained Sarah Kasman, a registered dietitian with Copeman Healthcare. "Your body is used to eating a certain way, so any unwanted changes could cause it to react." These symptoms, along with issues like persistent headaches, could be a sign that you're not getting the calories your body needs. While there are often changes you can make to feel better — headaches may be the result of dehydration, for example — and you should give yourself time to adjust, it's important that you listen to your body and know when it's had enough.
2. You Find Yourself Overeating Frequently
It's a common mistake Kasman warned against: many people believe that, since they're fasting for hours (or a whole day) at a time, they can eat whatever they want. "Don't use fasting as an excuse — the goal is ultimately to develop healthy and sustainable eating patterns to reach your goals," she told POPSUGAR. If overeating during that window is a mental game you can't seem to win, intermittent fasting may not be right for you — and there's nothing wrong with that. "Any dietary change should, for the most part, be maintainable in the long run," Kasman said. "Intermittent fasting might not always work with your lifestyle, so you need to take that into consideration."
3. You Have Certain Medical Conditions
Intermittent fasting can border on dangerous, depending on your medical history. "You are more sensitive to fasting if you have an underlying medical condition such as diabetes where you are taking medications that can exacerbate symptoms and be life threatening," Janette Nesheiwat, MD, who specializes in family and emergency medicine, told POPSUGAR. "Pregnant women, children, and those with weak immune systems — such as those who are HIV positive or undergoing chemotherapy — should all avoid fasting." Dr. Nesheiwat explained that fasting can result in grave side effects, such as hypoglycemia, metabolic disturbances, and seizures or electrolyte abnormalities.
Even something as seemingly harmless as an antibiotic can be problematic. "I would caution against intermittent fasting if you're on antibiotics as well, because many of them require a small amount of food so you don't have an upset stomach," explained Vanessa Rissetto, MS, RD, CDN. In fact, there are a number of medications — both prescription and over the counter — that are best taken with food, so discuss your plans with your doctor before deciding whether or not intermittent fasting fits into your life.