Can you eat during intermittent fasting?
The obvious answer would seem to be “no.” The whole point of fasting is that you don’t eat any food, right?
But according to recent research, you may actually be able to eat a small snack during a fast without missing out on any benefits—in fact, the snack could actually help you fast for even longer.
You can’t eat just anything though; the food has to fit certain criteria. Let’s take a look at what the research says, how to incorporate a snack into your fast, and what foods you can eat during intermittent fasting.
You Can Eat During a Fast (It Just Has to Be the Right Food)
Back in 2020, researchers ran a study on intermittent fasting for weight loss. Overweight participants were split into two groups: the first group ate normally, while the second group followed a pretty 14/10 daily fasting protocol (that’s 14 hours of fasting with a 10-hour eating window).
However, the fasting program had an unusual addition: every day, at hour 12, participants ate a “fasting snack”—a small, low-carb, high-fat snack designed to curb their hunger. Researchers wanted to know if eating something small would negate the benefits of fasting.
As it turns out, the snack did NOT negate any fasting benefits. Participants in the fasting group still showed significant weight loss and improved blood sugar levels, and their results were better than those in the standard diet group[*].
The researchers concluded that you can eat a small snack during a fast and still get all the benefits of intermittent fasting. It may help with hunger and actually allow you to fast longer.
However, the snack you eat during fasting has to fit a certain set of criteria.
What Can You Eat During a Fast?
The snack used in the study was carefully designed to be four things:
- Low-calorie
- High-fat
- Low-carb
- Low-protein
Essentially, participants ate a small amount of food (under ~150 calories) that was mostly fat, with little else.
The researchers chose this type of food for a reason. When you fast, your metabolism burns through available carbohydrate stores, and once they’re gone, it shifts into a state called ketosis—that’s when you burn fat for fuel instead of carbs[*].
Ketosis is at least partially responsible for a lot of the benefits of fasting, including stable blood sugar, increased mental clarity, decreased inflammation, and hunger suppression. But if you eat something that may spike your blood sugar, like carbs or protein, it will kick you out of ketosis.
For that reason, researchers chose to give participants a high-fat, low-carb snack, and if you choose to eat something small during a fast, you should probably do the same.
3 “Fasting Snacks” that Won’t Disrupt Your Intermittent Fast
I often eat a fasting snack on days when I have a lot to do, or when I want to push my fast further than usual. Here are three of my favorite things to eat:
1. Half an Avocado
Avocados are almost entirely fat, as well as healthy fiber that your body doesn’t digest (meaning it won’t affect your fast). They’re high in nutrients and low in carbs and protein.
That means half an avocado is an ideal fasting snack. I usually slice one up and add some sea salt to it for extra electrolytes.
2. A Spoonful (or Two) of Nut Butter
Nut butter is another good choice for a fasting snack. It’s nutrient-dense, high-fat, and low-protein, with almost no carbs. I like almond butter, macadamia butter, pistachio butter, and pecan butter the best, and will often have a couple spoonfuls in the middle of a fast.
Just make sure the nut butter you choose has no added sugar or carbs. You may also want to avoid peanut butter—peanuts are actually legumes, and are thus higher in carbs than many true nuts.
3. Bone Broth
Bone broth is a good fasting snack as well. It contains a few grams of collagen, which is protein, but is overall quite low in calories and is mostly fat, especially if you make it at home (some commercial brands may have the fat removed).
I like bone broth because it’s filling and warming. It’s a great way to satisfy your hunger and get a few more hours out of an extended fast.
Final Thoughts
It turns out you CAN eat during fasting! Having a small, high-fat snack won’t prevent any fasting benefits, and is actually a great strategy to use if you want to extend your fast longer than usual.
Just make sure you choose something high-fat, low-carb, and low-protein, and keep your snack under about 150 calories. Fasting snacks are a great tool to keep in your fasting toolbox for those days when you want to stick to your fasting schedule but are particularly hungry.
Give this a try and see what you think—and if you want to get even more benefits from fasting, try my 15-Day Metabolic Reset. It’s a free program designed to help you fast better, increase your metabolic flexibility, and become a leaner, more energetic version of yourself.
Aaargh – I’m doing a 72 hour fast and end of day two ate two spoons of peanut butter, thinking this was ok (read in “Fast like a Girl”) Now seeing that peanuts are a legume and probably best avoided as a fasting snack – have I ruined/broken my fast? Please advise, thank you.
Mindy says you should be your own N of 1. The best way to figure if you “ruined” (she also says that there are no failed fasts) your fast is to check your blood sugar after you eat. I think 30 minutes after to see if you are still in Ketosis.
Can you drink celcius during a fast?
I put chicory in my coffee. Is that okay to consume during a fast?
Can I put collagen in my tea if fasting?
Hi there,
I am just getting on to fasting and wondering if it is okay to eat a banana whilst fasting?
Hi Polly, Bananas are high carb containing around 27gm. So no, they don’t meet ‘high fat’ ‘low carb’ protocols and would break your fast. I recommend using an app to see the macros of your food- try CarbManager or My Fitness Pal, both have free options.
I have been doing 36 hrs fast….for past few weeks. I don’t have access to glucose monitor.
I have been taking a scoop of Athletics Greens every day….will this break my fast?
Do u think adding a spoon of chia seeds and drinking with water good idea while fasting?
Thanks
Hello Mindy,
Thanks for This article.
I bougth bonebroth wich have 16 kacl per 100 ml and 4gprotein per 100 ml and 0.8 gr salt per 100l
How Munch can I include In my fast? Can i drink 300 ML? (48 kacl and. 12 gr protein)
Wont the protein destroy the fast?
And is it ok to do two fasting snacks within 48 H or should I limit to 1?
Best Nanna
If I had pure coconut oil and coconut milk in my coffee and it slightly raised my blood sugar from 84 to 94, does that mean I’m not in a fasted state anymore?
Can you use heavy whipping cream in your coffee and not break a fast
What about bulletproof coffee? It contains coffee, MCT oil and grass fed butter
Does that mean a whole avocado will mess up a fast?
I drink matcha with Now Real Food ‘Organic Vanilla Monk Fruit’ drops as a “sweetener”. It contains glycerin as a carrier – does this break a fast? Thanks for your help!
Hi Mindy
I am doing a 36 hour fast and wanted to do a weight workout or HIIT workout in the middle of my fast. I usually have a protein shake after working out but as I am still fasting I don’t want to break my fast. Do I still need to eat something after working out?
Can I have chia seeds on the 72 hour fast?
This is great to see confirmed, as Ive been (very slowly) eating 1/2 an avo with salt after a workout while fasting, while having a small spoon of coconut oil before! Ive also been taking a spoon of tahini a day. My BMI is 21 and Im worried about losing muscle, so I had some unflavored whey protein with water on 2 days of my now 8 day fast, and that was not good at all. Ive noticed immediate fatigue and an overactive stomach (noisy). I wont make that mistake again. Maybe I’ll use bone broth next and to ease out.
I’m doing a 36-hour fast and at the 24-hour mark, I had a tablespoon of almond butter, which made me feel nauseous. Is that normal?
I am 66 years young, very active and trying to lose 20 pounds of belly fat! Im at the tail end of my 36 hour fast and have been fasting 24 hours once a week and 36 hours once a week for 5 weeks and have not lost anything!!! I am following the paleo diet , eating mostly meat and veggies. I “feast” on sudays and allow myself sweet potatoes and fruit. My blood sugar has gone up and not down. In the beginning when fasting my blood sugar would go down into the mid 70’s at the end of my 36 hour fast and today my fasting blood sugar was 94. I’m wondering if this fasting is really working or if I am damaging my body. My numbers seem like they are headed up instead of down. Does anyone have any experiece with this? I am so confused!
Nancy – nonexpert advice here – if you’re both limiting food *and* fasting a day and a half, you could possibly be kicking your body into the “starvation” mode that the old eat-barely-anything diet could produce, which gave yo-yo weight. You might try doing a 6-18 fast daily so that you mimic snack-food-hasn’t-been-invented-so-I-can’t-eat-between-meals eating, rather than there-is-no-food-to-eat diet. Good luck!