Keto and Intermittent Fasting Dominated 2018 — Here's Why They Are So Damn Popular

Updated on 12/27/2018 at 9:35 AM

You couldn't open up social media or attend a family function this year without someone mentioning one (or both) of the biggest diet crazes: intermittent fasting (IF) and the keto diet. But it's not just your cousin or fitness instructor who practices them; they have major celeb followings, too. Halle Berry, Vanessa Hudgens, and LeBron James all credit keto for their fit frames, while Hugh Jackman, Chris Hemsworth, and Jimmy Kimmel all swear by intermittent fasting.

And they're not just buzzwords; these approaches to eating, which each have a fervent following, have helped countless people lose weight and transform their lives. While both diets can be done simultaneously, they are wildly different. We broke down the ins and outs of each diet, including what (and when) you can eat, what to avoid, and how to do it successfully.

As of now, it looks like there's no slowing down on these crazes into 2019. If either of them appeal to you, keep reading to find out how to incorporate keto and/or IF into your life.

Keto Diet: What Is It?

The keto diet is a high-fat, moderate-protein, super-low-carb diet. When your body is running on so few carbs, it enters a state of ketosis, during which it starts burning fat for fuel instead of glucose (your body processes glucose from carbs).

On the keto diet, the macronutrient profile should be close to 70 to 80 percent fat, 15 to 20 percent protein, and five to 10 percent carbs, according to Catherine Metzgar, PhD, RD, a clinical team member at Virta Health. You should aim to keep your carbs at 50 grams a day or fewer, although every person is different and may have varying thresholds of ketosis.

If you aren't sure if your body is in ketosis, you can test it with urine strips, which let you know how many ketones your body is producing.

Ket Diet: The Best Fats and Oils

When it comes to fat on the keto diet, you want to make sure you're eating quality fats. Anna Barnwell, MPH, MSW, a member of the Virta Health team, explained in a blog post that a majority of your dietary fat should come from monounsaturated and saturated fats. You should be cautious of polyunsaturated fats like corn, sunflower, and peanut oils since your body cannot tolerate them well in large amounts.

Monounsaturated Fats

Animal fats
Avocado oil
Bacon
Canola oil
High-oleic safflower oil
Lard
Macadamia nut oil
Olive oil
Sausage

Saturated Fats

Beef (suet)
Butter
Cheese
Coconut oil
Cream
Lamb
Palm oil

Polyunsaturated Fats

Flaxseed oil (an alternative for vegetarians and vegans)
Omega-3
Omega-6

Keto Diet: Proteins You Can Have

A common misconception about the keto diet is that you can consume all the protein you want. Eating too much protein can prevent you from reaching nutritional ketosis. Here are the protein sources you can consume on the keto diet.

Bacon
Canned tuna
Chicken
Crab
Deli meat
Eggs
Ground beef
Ground turkey
Ham
Lobster
Lox
Prosciutto
Pork
Pork sausage
Salami
Salmon
Shrimp
Steak
Tuna

Keto Diet: Vegetables You Can Have

In order to reach nutritional ketosis, you'll need to eat more than just protein and fats. Here are some great veggie options to include in your diet.

Artichoke
Artichoke hearts
Asparagus
Bell peppers
Broccoli
Cauliflower
Celery
Cucumbers
Eggplant
Green beans
Jicama
Kale
Lettuce
Mushrooms
Onions
Radishes
Romaine
Spinach
Zucchini

Keto Diet: The Dairy You Can Have

Unlike most diets, dairy is actually approved on the keto diet. Here are some items to toss in your cart the next time you're shopping.

Alfredo sauce
Butter
Cheese sticks
Cottage cheese
Cream cheese
Hard cheeses (Parmesan, Swiss, feta, and cheddar)
Heavy cream
Mayonnaise
Soft cheeses (brie, mozzarella, Monterey Jack, and blue cheese)
Sour cream
Yogurt — full fat

Keto Diet: Fruits You Can Have

Some fruits are high in sugar, but there's no need to cut out all fruits on the keto diet. You've just got to make sure you're eating the right fruits. Stock up on these fruits during your next grocery store run.

Avocados
Blackberries
Blueberries
Cantaloupe
Cherries
Grapefruit
Kiwis
Lemons
Limes
Peaches
Raspberries
Strawberries
Watermelon

Although these fruits are keto-approved, it's important you track your total carbs to make sure you're in a state of ketosis.

Keto Diet: Expert Tips

If you want to successfully follow the keto diet, experts say to do the following:

Eat more salt.
Eat more magnesium-rich foods.
Don't do the dirty keto diet.
Be consistent for two to four months to see results.

Intermittent Fasting: What Is It?

Intermittent fasting (IF) isn't necessarily about what you eat, but when you eat it. IF refers to a way of eating that alternates between periods of not eating (fasting) and periods of eating (sometimes called your "feeding" or "feasting window"). This diet is supposed to decrease insulin levels, increase human growth hormone, improve digestion and mood, and boost weight loss.

Intermittent Fasting: The Different Types

There are several different ways to do IF, and it's not a one-size-fits-all diet. The most popular forms of intermittent fasting are:

Leangains: The most popular form of Leangains is fasting for 16 hours and eating within an eight-hour window each day. If that seems too extreme, you can practice Leangains with 14:10 or 12:12 and work your way up to a 16-hour fasting period.
5:2, or Fast Diet: For two days each week (not consecutively), you eat around 500 calories a day. The other five days of the week, you eat normally, as if you weren't on a diet. Still, on eating days, you should not go over your daily calorie target (i.e., 2,000 calories a day).
Eat, Stop, Eat: Fasting for 24 hours once or twice a week, then eating however you want the other days of the week. This means 24 hours with absolutely no food.
20:4, or The Warrior Diet: Fasting for 20 hours and only eating within a four-hour window. This typically means just one large meal a day.
Alternate Day Fasting: Fast for one day (you can eat up to 500 calories on fasting days) and then eat normally the next day, and repeat throughout the week. It's similar to 5:2, just with more fasting days.

What You Can Drink While You're Fasting

Although food is off limits during your fasting period, you can still drink liquids. The key is to make sure they are calorie-free beverages and free of artificial sweeteners and flavors. To keep it simple, these are the three beverages you can drink on IF:

Coffee: Unfortunately, you can't add anything into your coffee when you're in your fasting window (like cream, milk, or sugar) because this will throw off your fasting window.
Tea: Same thing here — tea is only appropriate if it's free of sweeteners or additives.
Water: Whatever you do, don't skip out on drinking plenty of water throughout the day. This will prevent dehydration and help curb your hunger. You can also drink sparkling water as long as it is unflavored.

Expert Tips For Intermittent Fasting

To optimize your time on intermittent fasting, here are some expert-approved tips:

Fast for at least 12 hours a day (although 13 is ideal).
If you're looking to lose weight, you should still eat in a healthy calorie deficit during your feeding window, especially if you're doing Leangains (to calculate your calorie target, use this formula). If you're doing 5:2, you can eat more calories on your feasting days; you don't need to eat in a calorie deficit on those days since the two fasting days will give you an overall weekly deficit.
If you need some help, check out these five apps.
Curious what you should eat during your feeding window? Here's what the experts recommend and what one day of eating on intermittent fasting looks like.