This article has been reviewed by Jeannie Versagli, RD, LDN. Jeannie is a Registered Dietitian with the Academy of Nutrition and Dietetics, a national professional organization, and is licensed in nutrition with the State of Delaware.
by Nate Widom
You’ve likely heard of intermittent fasting. Various approaches exist, all touted as fast-track routes to weight loss. However, to registered dietitian Jeannie Versagli, depending on the method, intermittent fasting can be a misguided trend at best or a method with significant potential health consequences at worst. In her words, “There are other ways to manage a healthy lifestyle.”
Intermittent fasting is an eating pattern in which you eat as usual for a specific time and then eat a reduced amount or nothing outside the designated window. It’s proven effective for fat loss and can improve stress and metabolic health.1 Some of Jeannie’s clients even mention how the eating pattern has helped them “detox” physically and mentally.
Fasting has been done for thousands of years. It is part of many religious customs, and “our bodies are well-equipped to handle short periods of not eating,” per Healthline. While some report improved well-being and energy while fasting, others report hunger; it all depends on the person. There are several ways to do it – below are some popular examples.1
- The 16/8 Method involves eating only for 8 hours of the day. A portion of the remaining 16 hours will be taken up by sleep anyway, but you can still drink water, tea, and coffee during that time.
- The 5:2 Diet involves eating 500-600 calories for two non-sequential days of the week and eating as usual for the rest of the week.
- The Eat-Stop-Eat Method is when, once or twice a week, you fast from dinner one day and continue that fast until dinner the next day. With this method, you’ll fast for 24 hours.
Other methods exist, too, and could be as simple as skipping breakfast, not eating until noon, or not eating after dinner.1
One thing is for sure. Jeannie strongly discourages the more intense methods where you deny yourself food for long periods, like a 5:2 diet and the Eat-Stop-Eat. “You’re really depriving your body of nutrients, and you don’t have to do that to achieve the end results,” she explains. “There’s a lot of consequences,” such as irritability, fatigue, and dehydration. Jeannie recommends a less intense plan like the 16/8 for those who want to try intermittent fasting. “It’s not such a shock to your system. Your blood sugar levels are going to be relatively stable. If you’re eating a high-fiber diet, you can include all of your nutrients for the most part during that day.”
⚠ No matter what, talk to a dietitian
Intermittent fasting can cause serious health problems for some, no matter the method and how often it’s done. After all, intermittent fasting can alter insulin levels and create hormonal changes. Therefore, Jeannie recommends always speaking to a dietitian if you’re considering trying any intermittent fasting plan. It’s advised the groups below never try it:
- Those with diabetes and prediabetes
- Women going through menstruation
- Nursing or pregnant women
- People with a history of eating disorders
- Young children and teenagers
- People who are immunocompromised
- Athletes (due to food supplying energy, athletes will not be able to perform at their best)
You’ll also need to consider how you feel when you don’t eat for a while. Are you hungry and miserable? When you’re food-deprived, you may experience irritability, moodiness, and fatigue. Plus, if you suffer from anxiety and depression, hunger may intensify it.
If you don’t have any conditions where it’s ill-advised, intermittent fasting can be helpful in the short term. When performed responsibly, it can result in weight loss and even lessen stress in quick periods. But it isn’t easy to keep up long-term. “Yeah, you can lose weight [long-term] on intermittent fasting,” Jeannie says. “But it’s not for everybody. You don’t have to go down that road to accomplish the same thing.”
“You’re really depriving your body of nutrients, and you don’t have to do that to achieve the end results.”
This is because no matter what weight loss method you want to use, you must be as consistent as possible. If you are inconsistent over the long haul, you’ll end up gaining weight back. In terms of intermittent fasting specifically, most of Jeannie’s clients cannot keep up. It really can be restrictive! “There are some positive effects, but is it something that you can do long-term?” Jeannie asks. “It’s really hard, especially for someone trying to manage their weight because they want to eat!”
And yes, with consistency, fasting can produce results. However, in the long term, the traditional method of losing weight does, too. “At the end of the day, the results are always the same,” Jeannie says. “You’re going to have the same results if you live a normal lifestyle, eat well, and exercise… If you’re taking in good sources of antioxidants and being mindful of getting your omega 3s, and you’re eating lean proteins, all that [weight loss] is going to happen anyway.” Both intermittent fasting and simply following a healthy diet can produce a similar number of pounds lost, but which method provides a more stable (and likely more enjoyable) journey for most?
The traditional method of losing weight involves burning more calories than you consume. It also involves eating nutritious, unprocessed foods and aiming for 150 minutes of moderate-intensity or 75 minutes of high-intensity exercise per week. Make sure you’re meeting all your micros and fiber requirements!
Even though Jeannie sees how intermittent fasting can work for some, she’s still skeptical of the trend for a few reasons. First, it’s not a diet; it’s an eating pattern, which doesn’t necessarily teach people proper nutrition. “Have you really learned how to eat well?” Jeannie asks. Intermittent fasting doesn’t stipulate the quality of the food you consume, only when and/or how much. Done irresponsibly, the method can leave you starved for many of the nutrients you need to thrive. Also, the research on how intermittent fasting affects human health over time is limited. Jeannie points out, “there’s been a lot of studies on animals, but very little long-term research on humans.”
“You’re going to have the same results if you live a normal lifestyle, eat well, and exercise.”
Ultimately, Jeannie urges people to speak to a dietitian, assess whether intermittent fasting is right for them, and develop a customized plan. “When talking about health… what we’re looking for here is lifestyle changes,” Jeannie concludes.
Writer’s Note
You don’t need to deprive yourself of foods you enjoy to lose weight! As the third-place winner in the 2024 HAC Lifestyle Challenge, I credit my win to modifying the foods I already love to be more nutritious and working out a few times a week. To learn more about my story and these modifications, click here.
References:
1. https://www.healthline.com/nutrition/what-is-intermittent-fasting
