A lot of people start intermittent fasting with one question in mind: What should I eat? But the flipside matters just as much – what should I avoid?
To be completely honest, even small slip-ups can throw off your results, especially if you’re putting in the effort to stick to your eating and fasting windows. And it’s not just about calories & counting – some foods can mess with your blood sugar, trigger cravings, or keep you hungrier than before.
But, the good news? Well, once you know the big offenders, it’s easier to dodge them and focus on the foods that make fasting feel doable.
Let’s walk through what foods to avoid during intermittent fasting, why it matters, and what you can grab instead.
Why Certain Foods Can Disrupt Your Fast?
When you’re fasting, the whole point is to give your body a break from digesting food so it can focus on other things, such as burning stored energy, regulating blood sugar, and maybe even reducing a little inflammation. The problem is, some foods (and drinks, of course) pull you right out of that zone before you even realize it.
Sugary snacks are definitely one of the fastest ways to spike your insulin, which shuts down fat-burning and can leave you hungrier than you were before that meal.
The same thing is with refined carbs. Your body digests them quickly, blood sugar shoots up, then crashes. Suddenly, you’re not just thinking about your next meal – you’re fighting off cravings that feel urgent.
Also, greasy, heavy foods can be just as disruptive. To be fair, they won’t necessarily raise blood sugar the same way as sugar snacks, but they can strain digestion and cause that sluggish, weighed-down feeling that makes fasting harder the next day.
And yes, even “healthy” drinks like smoothies or fancy coffee orders can sneak in enough calories to break your fast without you realizing it.
If you want the full benefits of intermittent fasting, it’s worth knowing what to avoid during intermittent fasting and saving those foods for the right time in your eating window. That’s why my guide to foods to avoid while fasting is going to clarify everything for you.
Common Foods to Avoid While Intermittent Fasting
When people talk about intermittent fasting, the focus is usually on what to eat when your eating window opens.
Yes, that matters for sure, but the flip side – knowing what foods to avoid while intermittent fasting – is just as important. I’ve seen people crush their fast all morning, only to undo all that progress with one snack or drink they didn’t even think twice about.
The thing is, when you’re fasting, your body’s running on a different rhythm, right? So, your insulin is lower, your digestion gets a break, and you’re basically primed to burn fat for energy.
But the wrong food at the wrong time? It can throw that off in minutes. We’re talking about blood sugar spiking, cravings kicking in, and your hunger control going out the window.
Here are the big categories of foods to avoid during intermittent fasting if you actually want the benefits you’ve been working for. And I’m not saying these foods are “bad” in general – just know when to eat them, and when they’re going to work against you.
Sugary Foods and Desserts
Let’s start with the basic foods to avoid while intermittent fasting: sugar, snacks, and desserts. Candy, pastries, donuts – basically anything that’s loaded with sugar – can mess with your fast in a minute.
These aren’t just empty calories; they’re a direct hit to your blood sugar. Once it spikes, your insulin level jumps, and your body switches out of fat-burning mode.
That’s why you’ll often get that quick burst of energy, followed by a crash that leaves you hunting for more and more sugar. If you’re serious about keeping cravings down while fasting, save the desserts for a planned treat during your eating window, not mid-fast.
Refined Carbs
White bread, regular pasta, crackers – these might seem harmless compared to candy & the above-mentioned snacks, but your body treats them almost the same way, believe it or not.
They break down fast, raise blood sugar, and don’t keep you full for long. To simplify this: it means you’re hungrier sooner, and fasting becomes more of a mental fight & challenge than it needs to be.
If you’re opening your eating window, go for carbs that have some fiber and nutrients in them. They’ll give you steady energy instead of a spike and crash. You can always check the intermittent fasting plan I’ve written on my blog to get some ideas.
Processed Snacks and Junk Food
Chips, packaged crackers, fast food fries – these are a double problem. They’re high in calories and low in nutrition, and they’re designed to be so addictive.
You think you’ll have a handful and move on, but suddenly the bag’s empty, and you’re wondering what just happened?!
Also, these snacks and junk foods tend to be high in sodium and unhealthy fats, which can leave you feeling bloated and sluggish. Not exactly the feeling you want after sticking to a fast, am I right?
High-Calorie Drinks
This one actually surprises a lot of you. Coffee loaded with cream and syrup, smoothies, soda, energy drinks, even alcohol – they can all break your fast faster than you think.
To be honest, liquid calories go down easily, but they still trigger the same responses in your body as solid food. Which means? Well, this means the fat-burning pause button gets hit, and your hunger can spike right after.
If you want to drink something during your fasting hours, stick to water, black coffee, or unsweetened tea. It’s boring, I know, but it keeps you in that fasting zone.
Final Thoughts
If there’s one thing I’ve learned watching people try intermittent fasting, it’s that the “what foods to avoid” part is way easier to ignore than the “what to eat” part. But skipping it?
As mentioned multiple times in this article, that’s where things can go sideways fast. Choosing the right foods isn’t about being flawless – it’s about stacking the odds in your favor so you’re not battling cravings every other hour.
When you cut out the usual troublemakers – sugary foods, refined carbs, processed snacks, high-calorie drinks – you make fasting feel lighter, almost easier, because your body isn’t constantly spiking and crashing. And that’s the whole point: make it something you can actually stick to.
So yes, start simple.
Remember to be consistent. Pay attention to how your body feels when you avoid the stuff that messes with your progress.
And if you need ideas to keep your eating window full of good food that still tastes amazing, there’s a whole world of recipes and guides here on Fit Men Cook waiting for you.
FAQs About Foods to Avoid While Intermittent Fasting
Foods to avoid while intermittent fasting include sugary snacks, refined carbs, fried foods, and processed junk. These can spike blood sugar, trigger cravings, and make fasting harder to maintain.
Yes, artificial sweeteners can sometimes break a fast by triggering an insulin response. While calorie-free, they may still affect hunger and cravings. Best to skip them during fasting hours.
The best food while intermittent fasting is nutrient-dense, whole food – lean proteins, vegetables, healthy fats, and slow-digesting carbs that support satiety and steady energy during your eating window.
Yes, there are. Foods that make fasting harder include high-sugar treats, refined carbs, and greasy processed snacks. These can cause energy crashes and stronger hunger during your next fast.
Drinks safe during intermittent fasting are plain water, black coffee, and unsweetened tea. Avoid any with sugar, milk, or cream, as they can break your fast.
