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Before changing the way you eat and altering your diet in any significant way, please speak with a health professional to make sure it’s the best decision for you.

So your friend lost 15 pounds and your dad can’t stop raving about the blood sugar-regulating merits of intermittent fasting (IF). Some people might think it’s just a fancy-pants name for skipping breakfast — but they’d be wrong.

There’s a knack to IF that means you can get it wrong. And making these (completely understandable) mistakes could mean you’re not seeing the full benefits of the diet. Or, worse still, you could actively be making yourself miserable or dehydrated.

Maybe you’ve carved out a routine that feels good, but for some reason the benefits keep passing you by. Or maybe you have a regimen that helps you shed pounds but has you feeling tired and sh*tty the rest of the time — and that won’t work either.

For the record, IF doesn’t work for everyone. But you won’t know if it’s the eating regimen for you unless you give it the best chance to take effect.

We’ve compiled some of the biggest mistakes you could be making on your IF plan.

IF at first you don’t succeed…

1. You’re jumping into IF too fast

There are levels to this.

The biggest reason most diets don’t reap rewards is their extreme departure from our usual, natural way of eating. They can often feel impossible to maintain.

Just a thought: If you’re new to IF and you’re accustomed to eating every 2 hours on the hour, maybe don’t throw yourself into a hardcore 24-hour fast from hell. An adjustment period is natural, but it should feel good.

Your body is a surprisingly good communicator. It’ll let you know if it feels like crap. And it goes without saying that starving yourself for 24 hours out of absolutely nowhere is going to feel like crap.

If you’re adamant about the concept of fasting, start with a beginner’s 12:12 method: Fast for 12 hours per day and eat within the other 12-hour window.

That’s probably pretty close to what you’re used to doing anyway, and who knows — it might be the only sustainable way to follow along.

Once that feels comfortable, you can level up to 16:8, where you eat during an 8-hour window and fast during the rest of your day. The great thing about IF is its flexibility, so choose a plan that helps you stick to a time period without feeling terrible.

2. You’re choosing the wrong plan for your lifestyle

Don’t set yourself up for misery by signing up for something you know will cramp your (life)style. Having a few miserable days before lapsing into a 24-hour cake party won’t cut it — IF is about making change you can maintain.

If you’re a night owl, don’t plan to start your fast at 6 p.m. If you’re a daily gym-goer who Instagrams your WOD every morning, and you simply will not sacrifice your daily Spin, don’t choose a plan that severely restricts calories a few days a week.

We don’t know your lifestyle (if we did, that would be creepy as heck). You’re the expert. So you’ve got to do you if you want any habit to stick.

3. You’re eating too much during the eating window

This is the most common trap people fall into with IF. If you’ve chosen a particularly restrictive regimen that leaves you hangry AF for hours of the day, you’re likely to go a wee bit overboard the moment the clock says “It’s time to eat.”

Recent research suggests that restrictive diets often don’t work because we tend to become so emotionally (and physically) starved that when we do allow ourselves to eat, we go hog wild and overeat in a fit of deprivation.Benton D, et al. (2017). Reducing calorie intake may not help you lose body weight. DOI: 10.1177/1745691617690878

Any diet that has you preoccupied with your next meal is a recipe for a binge. Make sure you’re not allowing yourself to feel unnecessarily hungry for long periods of time.

You can achieve this by choosing the right foods to chow down on during your eating hours.

4. You’re *not eating enough* during the eating window

Wait, what? Yep, not eating enough is also a legit cause of weight gain, and here’s why.

In addition to setting you up to eat too much of less-healthy foods during your eating hours, not eating enough cannibalizes your muscle mass, causing your metabolism to slow.

Without that metabolic muscle mass, you may be sabotaging your ability to burn fat in the future.

The challenge with IF is this: Because you eat according to some arbitrary time-based rules rather than listen to your body’s cues, it’s really difficult to know your true needs.

If you’re thinking about having a go at an IF regimen, it may be best to consult a registered dietitian to help you assess and meet your nutritional needs safely.

5. You’re ignoring the *what* in favor of the *when*

IF is a time-centered diet, and most plans don’t give any explicit rules about the types of food to eat during your eating window. But that’s not an open invitation to subsist on french fries, milkshakes, and beer alone.

Fasting isn’t magic. In addition to some small metabolic advantages, its primary impact on weight loss (if it even has one) is largely that you limit your eating hours and thus the amount of calories you consume.Stockman M-C, et al. (2019). Intermittent fasting: Is the wait worth the weight? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5959807/

Unfortunately, you can quickly undo that effect by choosing the wrong kinds of foods. Shift your perspective from a “treating yourself” mentality during your eating hours to one that revolves around eating the most nutrient-dense, nourishing foods you can get your hands on.

We recommend trying to make sure every meal or snack has a combination of fiber, protein, and healthy fats to help fill you up and carry you through your fasting phase.

6. You’re not drinking enough

Intermittent fasting does not mean intermittent drinking.

Your IF regimen might have you refraining from food, but it’s always better to have water on hand, especially since you’re missing out on the hydration you’d often get from fruits and veggies.

A 2009 study found that people ate at certain times of the day whether they were hungry or not and generally drank water as a sidekick to meals whether they were thirsty or not.McKiernan F, et al. (2009). Thirst-drinking, hunger-eating; tight coupling? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671201/

This means that if you’re skipping meals, it’s naturally important to stay vigilant about drinking enough water through your fasting period.

Dehydration can lead to muscle cramps, headaches, and hunger pangs, so always make sure you’re sipping H2O between (and during) feasts.

If you’ve followed all the rules and you’re still struggling, don’t be hard on yourself. It’s probably not you — the diet simply isn’t easy or successful for everyone.

Applaud yourself for even trying a new diet plan, and know that you’re so far from alone in having a hard time restricting the way you eat. According to a 2016 research review, intermittent fasting has a dropout rate of up to 31 percent.

Try to focus more on what your body tells you than on what the clock says. This way, you’re much more likely to get the nutrition your body needs, and you’ll feel better in the process.

IF is no walk in the park — it takes dedication and persistence. By eliminating certain faux pas from your process, you can put together the clearest picture of how your body responds to IF and whether it’s the right eating regimen for you.

Here’s our rundown of the side effects and health benefits of IF, if you’re looking for more information.