Here's why one RD says you should proceed with caution before jumping on this hangry diet trend.

By Jessica Cording, MS, RD, CDN
Updated: January 04, 2019
Photo: mactrunk/Getty Images

Any dietitian or nutritionist will likely admit that they have a list of the questions most commonly asked by clients. Typically, that list evolves based on the latest diet and wellness trends-a couple years ago, everyone wanted to talk about the paleo diet, and while the Whole30 craze is still alive and well, I get a lot more questions now about the keto diet. Another big one right now: intermittent fasting.

What is intermittent fasting?

More of an "eating pattern" than an actual diet, intermittent fasting (IF) is characterized by cycling between periods of eating and fasting. There are several approaches, but the most popular are those that involve either daily 16-hour fasts in which you eat all your food in an eight-hour window, or an IF pattern in which someone fasts for 24 hours, usually twice per week. There's also the 5:2 plan, where you eat "normally" for five days and then for the other two days, consume only about 500 to 600 calories. While there are exceptions, in general, IF patterns tell you when to eat, but not necessarily what to eat.

What are the intermittent fasting benefits?

Now's probably the time to be up-front: I am not a fan of intermittent fasting.

While research has shown some potential benefits to IF, as a dietitian and health coach who focuses on sustainable lifestyle approaches to wellness, I can't quite get on board with recommending that someone just not eat. Fasting can be a slippery slope to unhealthy habits and a screwy relationship with food.

That doesn't mean I won't work with someone who wants to explore IF-it just means we need to discuss why you're interested in using this method to reach your goals and whether there might be other options to support your efforts in a more sustainable way.

Weight management is probably the number-one reason people ask me about IF. While studies have shown that intermittent fasting may help with weight loss and improved metabolism, this eating pattern has also been researched for its impact on insulin resistance, as well as for its potential to decrease inflammation, enhance cell repair, and support a healthy gastrointestinal tract. Sounds great, right? Not so fast.

Here are the health concerns about intermittent fasting.

The main issue that comes up is sustainability-meaning, can you maintain this way of eating, and, more so, should you? Many people find they feel great while following an IF plan but struggle when they try to stick with it for a prolonged period. Figuring out how to fit those fasting and eating periods into your work and social life, and fuel and refuel appropriately around your workouts, can be a logistical nightmare and also a health challenge. This is especially true if you work long days, wake up really early, or go to bed very late. It can also be tricky for people who lack a sense of routine in their day-to-day life. While some people have found it motivates them to get into a more consistent schedule, many have gotten frustrated for not being able to keep it up. When your self-esteem takes a hit like that, it can trickle into other areas of your life. (Must read: Why You Should Give Up Restrictive Dieting Once and for All)

I've seen many people who hop on and off the IF bandwagon start to feel out of touch with their hunger and fullness cues. This mind-body disconnect can make it difficult to establish an overall healthy diet for the long haul. For certain people, this could lead to or resurface disordered eating behaviors. (BTW, have you heard of orthorexia? It's the eating disorder masking itself as a healthy diet.)

If you still want to try intermittent fasting...

With all that said, if you've consulted your doctor and/or your certified nutritionist, and intermittent fasting still sounds like something you want to try, here are a few tips to keep in mind.

Tune in to the why.

Are you hoping to lose weight with intermittent fasting? Is there another health reason? Have you tried other approaches to meeting your goal? If yes, why didn't they work? Zeroing in on what you hope to accomplish and the motivations behind it will help you prioritize foods and strategies that help you get there in a healthy way.

Consider your approach.

Decide whether a daily 16/8 approach or something more like a weekly 5:2 plan will work better for your stomach and schedule. When do you usually get hungry throughout the day? What time do you wake up and go to bed? How often and what time of the day do you work out? All of this will help determine when you are in fasting mode. For example, if you routinely hit the sack after midnight, closing the kitchen at 6 p.m. probably won't be so easy.

Make intermittent fasting work around you.

Take into account when you tend to go to sleep and wake up. Then factor in when you like to exercise. What is your work schedule like? How about your social life? This will help you figure out how to spread out your fasting and eating phases, so you're never starving, cranky, and struggling to maintain your energy and focus.

Have an exit strategy.

Are you thinking of IF as a long-term plan? While I don't recommend it as such, if you intend to be intermittently fasting forever (whew), you better make sure you have a plan to help reintroduce a more regular eating schedule back into your life. I see a lot of people trip up when they try to come off an IF cycle because they can't seem to get reacquainted with their appetite and hunger cues. If you're serious about doing IF in a healthy, mindful way, come up with a post-IF plan (perhaps together with a dietitian) so you have something to guide you.

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Comments (23)

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January 5, 2019
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January 9, 2019
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Anonymous
September 23, 2018
Individual results may vary. For ME, doing ketogenic diet in conjunction with 15:8 intermittent fasting and a 24-hour once a week, for the first time in my adult life (35+ years), I'm actually having NORMAL hunger/satiety cycles. My entire adult life, I've been nearly constantly hungry. I had no natural "stop" signal when eating. Without an exceptionally high level of planning and willpower, I would eat until my stomach was physically distended. And then I'd be uncomfortable for a while, but hungry again in an hour. I tried over a dozen different diet and exercise programs, including all the ones that are "supposed" to work, according to the research. My numbers would look good for about 60 days, but I could never keep them up, because nothing fixed my hunger. Since starting keto & IF, I now remember what it feels like to be satiated without being bloated and distended. I now remember what it feels like to not need a snack every 2 hours. I skip breakfast because I wake up feeling full, and I'm not hungry til mid-day. On the rare occasion that's not the case, guess what? I eat! So sustainability, and a normal, healthy relationship with food, is EXACTLY why keto + intermittent fasting is working for me. It's the first time I've had it in over 35 years.
Anonymous
July 4, 2018
You obviously have a chip on your shoulder. And the only “risk” you cite is potentially developing anorexia or not sticking to it. How successful has daily calorie reduction been at bending the obesity curve?
nbdysfool3
June 10, 2018
Another article published from someone who doesn't understand the premise. Do not eat when you first wake, let your body use fat for energy the first few hours. I wake daily at 7-730a get some lemon water w/apple cider vinegar in it. I have 10-12 8oz. glasses of regular water daily. and do light walking 5 mornings a week (about 3 miles). I have been doing this for a long time and have always had a pretty clean diet. For some reason over the years I have still managed to gain weight steadily. Since starting the IF plan 6 months ago I have lost 35 pounds. All that changed was I eat 3 meals a day between the hours of noon and 8pm. IF works....my diet is primarily lean beef, fish, chicken and eggs for protein. a lot of vegetables and healthy fats. People need throw away any 90% of the unhealthy foods they are eating. Stop making excuses for lousy food choices and start eating and living clean. I see obese children all the time and it saddens me that the parents are allowing this. Wake uo america, IF is sustainable, lIfe and food are a matter of healthy habits.....You're either going to fix your habits or end up on medicines that will only make you sicker! food for though.....It your food like it's medicine now or take medication as food later! your choice!!!!!! Stop listening to bad advice, try it and form your own opinion on new things...what do you have to lose, oh yeah, weight! You can keep doing what you're doing and keep[ getting the same results or you can approach this logically and make real change. I did it and you can too. ps. "NOTHING TASTES AS GOOD AS BEING HEALTHY FEELS"
Anonymous
May 27, 2018
Agree totally! It appears that this article is trying to come across as informed, but is not. Read the book "The End of Alzheimer's" by Dr Dale Breseden. He has studied it for 28 yrs and it is not anecdotal evidence. His Recode program includes keto and intermittent fasting, and he has REVERSED alzheimers in many patients. Why havent you heard this...think about how much big pharm stands to lose.
Anonymous
November 18, 2017
Totally agree with Paul here. Can I start writing articles for you guys, it seems all I need is an opinion. So people may not stick with IF...really...well I'll be darned. Most folks don't stick with ANY plan, IF or not. Give me a break, this article was terrible. Just about any diet works so long as you stick to it. There is far too much clinical evidence that shows just how great IF is for you. And if I may - I've counted points, calories, carbohydrates and macros. I've driven myself crazy. With IF I simply eat all the healthy things in moderation and the only thing I keep track of is time. "Shape", please let me know if you'd like me to write an article for you that the sun is hot.
Anonymous
November 17, 2017
The articles main criticism of IF is that people may not stick to it. That is just stupid! If you smoke should you not quit because you may not stick to it? There is tons of evidence that IF is really good for you. Not only weight loss, but decreased risk of diabetes, decreased uric acid levels, decreased cholesterol. It also increases autophagy, mitochondrial health and DNA repair. I lost 60 pounds, have amazingly increased energy, am off all meds and my knees no longer bother me. Yes you have to stick to it but its worth it. It improves your relationship with food if you are thoughtful about it. This is a trash article typical of the dumbing down of America so prevalent these days.