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Before changing your diet in any significant way, please speak with a health professional to make sure it’s the best decision for you.
Although the word “fasting” sounds pretty ominous, intermittent fasting (IF) is causing quite a stir in the overcrowded world of dieting.
A decent amount of research (although with less-than-massive sample sizes) suggests that the diet can lead to weight loss and improved blood sugar levels. No wonder everyone and their aunt seems to be jumping on the IF bandwagon.
Maybe the appeal is in the lack of food rules: There are restrictions on when you can eat but not necessarily on what you can eat.
However, the what is also important. Should you be downing pints of ice cream and bags of chips in between fasts? Probably not. That’s why we’ve come up with a list of the best foods to include in your IF life.
Best foods to eat while intermittent fasting
With intermittent fasting, you’ll want to stick to your fasting and eating windows each day. There’s less of a focus on WHAT to eat, although it’s still important.
Basically, the best foods to eat while intermittent fasting are the best foods to eat no matter what. They include things like avocado, potatoes, cruciferous veggies, fish, seafood, whole grains, nuts, and fermented foods. It’s also key to remember water as a part of your daily routine.
“There are no specifications or restrictions about what type or how much food to eat while following intermittent fasting,” says Lauren Harris-Pincus, RDN, author of The Protein-Packed Breakfast Club.
But Mary Purdy, RDN, chair of Dietitians in Integrative and Functional Medicine, counters by advising that “the benefits [of IF] are not likely to accompany consistent meals of Big Macs.”
Pincus and Purdy agree that a well-balanced diet is the key to losing weight, maintaining energy levels, and sticking with the diet.
“Anyone attempting to lose weight should focus on nutrient-dense foods like fruits, veggies, whole grains, nuts, beans, seeds, as well as dairy and lean proteins,” suggests Pincus.
Purdy adds, “My recommendations wouldn’t be very different from the foods I might normally suggest for improved health — high fiber, unprocessed, whole foods that offer variety and flavor.”
In other words, eat plenty of the below foods and you won’t end up in a hangry rage while fasting.
OK, OK — this isn’t technically a food, but it’s gosh-danged important for getting through IF.
Water is central to the health of basically every major organ in your body. You’d be foolish to avoid this as part of your fast. Your organs are pretty important for, ya know, being alive.
The amount of water each person should drink varies based on sex, height, weight, activity level, and climate. But a good measure is the color of your urine. You want it to be pale yellow at all times.
Dark yellow urine suggests dehydration, which can cause headaches, fatigue, and lightheadedness. Couple that with limited food and you’ve got a recipe for disaster — or, at the very least, really dark pee.
If the thought of plain water doesn’t excite you, add a squeeze of lemon juice, a few mint leaves, or some cucumber slices to your water.
Here’s why H2O is the champion.
It may seem counterintuitive to eat the highest-calorie fruit while trying to lose weight. But, because of their high unsaturated fat content, avocados will keep you full during even the fastiest of fasting periods.
Research from 2017 suggests unsaturated fats help keep your body full even when you don’t feel full. Your body gives off signals that it has enough food and isn’t about to go into emergency starvation mode. Unsaturated fats keep these signals going for longer, even if you feel a bit hungry in the middle of a fasting period.
A 2013 study even found that adding half an avocado to your lunch may keep you full for hours longer than if you hadn’t eaten that green, mushy gem.
Out of inspiration? We’ve got 36 avocado recipes to blow your mind.
3. Fish and seafood
There’s a reason the Dietary Guidelines for Americans suggest most adults eat 8 to 10 ounces of fish per week.
And if eating during limited windows is your bag, don’t you want more nutritional bang for your buck when you do chow down?
There are so many ways to cook fish that you’ll never run out of ideas.
4. Cruciferous veggies
Foods like broccoli, brussels sprouts, and cauliflower are all full of the f-word — fiber! (We know what you were thinking, and no, the f-word is not “farts.”)
When you’re eating during certain intervals, it’s crucial to eat fiber-rich foods that will keep you regular and help your poop factory run smoothly.
Research indicates that fiber can also make you feel full, which may be a good thing if you can’t eat again for 16 hours. Oof.
Cruciferous veggies can also help reduce your cancer risk. Learn more about anticancer foods here.
Repeat after us: Not all white foods are bad.
Case in point: Research in the ’90s found that potatoes were one of the most filling foods. And a 2012 study found that eating potatoes as part of a healthy diet could help with weight loss. (Sorry, but french fries and potato chips don’t count.)
We took a closer look at the link between potatoes and blood sugar.
6. Beans and legumes
Your favorite addition to chili may be your best friend on the IF lifestyle.
Food — specifically carbs — supplies energy for activity. We’re not telling you to carb-load to ridiculous levels, but it definitely wouldn’t hurt to throw some low calorie carbs like beans and legumes into your eating plan. This can keep you perked up during your fasting hours.
You know what the little critters in your gut like the most? Consistency and diversity. That means they aren’t happy when they’re hungry. And research suggests that when your gut isn’t happy, you may experience some irritating side effects, such as constipation.
To counteract this unpleasantness, add probiotic-rich foods — like kefir, kombucha, and sauerkraut — to your diet.
We spoke with the experts about how probiotics work in the body.
These staples of your favorite smoothie are ripe with vital nutrients. And that’s not even the best part.
A large 2016 study found that people who consumed a whole bunch of flavonoids, such as those in blueberries and strawberries, had smaller increases in BMI over a 14-year period than people who didn’t eat berries.
One large egg provides 6.24 grams of protein and cooks up in minutes. And getting as much protein as possible is important for keeping full and building muscle, especially when you’re eating less.
A 2010 study found that men who ate eggs for breakfast instead of a bagel were less hungry and ate less throughout the day.
In other words, when you’re looking for something to do during your fasting period, why not hard-boil the heck out of some eggs? Then, you can eat them when the time is right.
They may be higher in calories than many other snacks, but nuts contain something most snack foods don’t: good fats.
And if you’re worried about calories, don’t be! A 2012 study found that a 1-ounce serving of almonds (about 23 nuts) has 20 percent fewer calories than listed on the label.
According to the study, chewing doesn’t completely break down almond cell walls. This leaves a portion of the nut intact, and your body doesn’t absorb it during digestion. So if you eat almonds, they might not make as big a dent in your daily calorie intake as you thought.
Have a look at our ultimate guide to nuts.
11. Whole grains
Being on a diet and eating carbs seem like they belong in two different buckets. You’ll be super relieved to know that this isn’t always the case. Whole grains provide lots of fiber and protein, so eating a little goes a long way toward keeping you full.
We put whole-wheat and white pasta up against each other to see who’s best.
We’ve given you the lowdown on IF before, but here’s a little refresher for the new students in class. (You two in the back, stop texting!)
While the foods above will give you the most obvious benefits from the diet, it’s the “fasting” part of IF that provides the oomph.
There are loads of IF plans, but most focus on fasting for a certain number of hours in the day or days of the week.
Here’s a breakdown of the most popular IF models:
- The 12:12 method. Fast for 12 hours a day and eat within a 12-hour window. If you eat your last meal at 7 p.m. and have breakfast the next morning at 7 a.m., congratulations — you’re already an IF pro. (This is good for beginners.)
- The 20:4 method. Fast for a full 20 hours and allow yourself one 4-hour window to eat.
- The 16:8 method. Eat your daily food within an 8-hour window and fast for the remaining 16 hours.
- The 5:2 method. Eat whatever you want for 5 days out of the week. For the other 2 days, men can consume 600 calories and women can consume 500 calories.
For more info about different approaches to IF, check out our intermittent fasting guide.
There are risks to IF, such as tiredness, irritability, and headaches. Dehydration is also possible if you don’t drink enough water during fasting periods.
Research on rats suggests that IF may even contribute to infertility. And other research suggests that athletes might find that they break down muscle instead of building it due to the timing of when they work out in the energy cycle.
The fasting/feasting routine is also potentially unrealistic in the long term and may lead to binge eating during feasting periods, which won’t support any weight management goals.
If you eat the above foods during bouts of yo-yo dieting, they may not provide the nutritional benefits they usually would. When your body is under stress due to eating too few calories, it won’t use the nutrients you do take in to their fullest extent.
It’s best to talk with a registered dietitian before embarking on IF — it’s not for everyone.
How do I manage my hunger on IF?
Hunger is inevitable, but mild hunger is something you can definitely manage. Try sipping on calorie-free beverages like green tea or coffee, chewing on sugar-free gum, or good old-fashioned distraction.
After a while, your body should adjust to your eating window and you’ll feel less hungry during your fasting window.
HOWEVER, if you start to feel other symptoms beyond a gnawing at your stomach (like dizziness, extreme fatigue, confusion, lightheadedness, etc.), don’t be an IF hero — eat!!
Can I eat snacks on IF?
Ummm, ABSOLUTELY. Just make sure it’s within your eating window.
Some forms such of IF, such as time-restricted eating and Eat-Stop-Eat, tend to exclude snacks. These patterns generally involve eating two or three square meals per day and nothing else.
When’s the best time to exercise on IF?
Honestly, the best workout is one that gets done. Work out when it works best for you and you’ll still reap the benefits.
However, there are two other schools of thought on working out while fasting.
The first is that working out while fasted (toward the end of your fasting window, before you break the fast) helps you to burn more of your stored body fat. Some small studies support this theory, while others have found that fasting doesn’t make a difference in fat burning.
If weight loss is your goal, this may be an approach you want to try out.
Alternatively, trying to work out on a totally empty stomach may leave you feeling yucky.
Working out during your eating window (after a meal or two) may provide more energy to help you power through your workout. If you’re doing endurance exercise, it’s probably better to go with this approach and have a balanced meal before you get after it.