When you hear the word “fasting,” you probably think of gimmicky diets—and, um, feeling “hangry.” But a growing body of research suggests that cycling super low-calorie days into your normal eating plan could potentially improve your health (more on that later). But before you skip lunch and let your gut start growling, read on for everything you need to know about intermittent fasting.
In very basic terms, IF is occasional starvation done in a strategic way. The idea is to cycle between periods of regular eating and fasting, during which you severely restrict your calorie intake or don’t consume any food at all. Some people fast for hours, while some may go for a full day or longer.
Fasting isn’t one size fits all
“It’s not something that I personally recommend in my practice because I think there are lots of ways to get a jumpstart on weight loss without going cold turkey with food,” she explains. “You can instead focus on eating more vegetables and fruits. That way you’re focusing on picking healthy calories and adding nutrients. It’s a positive change as opposed to an all-or-nothing mindset.”
You also don’t know how you will react physically and mentally to calorie restriction, she adds. “You may not know how your body will respond to, say, low blood sugar,” Mills says. “Or, some people find that fasting seems like a piece of cake until around 3 o’clock, and then suddenly cravings come on and you end up eating all sorts of things you normally wouldn’t.”
The bottom line? “You have to consider how you personally are affected by restriction,” she says.
You should talk to a doctor before trying a fasting diet
Your personality is just one factor to consider before you try IF; your overall health is another.
“Whether you’re thinking about trying a fasting system for preventive reasons or as a treatment, the doctor should be involved,” Longo says. “There are many factors that must be considered, like your current diet, or whether you have diabetes or a metabolic disorder.”
Also, it’s important to determine with a health or nutrition professional what sort of system makes sense for your lifestyle.
“An athlete with a perfect pescatarian diet may benefit from only fasting twice a year,” Longo explains. “But someone with high cholesterol and excess abdominal fat may see more improvement by doing it more regularly.”
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The long-term effects of fasting diets aren’t well understood. Much of the research on the topic has been done across short time frames. And while experts have done some studies in humans and are doing more, a lot of the current info is from animal samples.
A lot more research needs to be done, Mills says. But if you are curious about incorporating fasting into your eating plan, you should ask a health professional to help you design a plan that ensures you are eating the right foods on both fasting and non-fasting days to guarantee you stay in good health.