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Sorry, Regina George, but butter isn’t a carb. It’s actually a fat, which means it’s keto diet friendly.

“Diet friendly?!” you might be thinking. What kind of diet includes BUTTER?

That would be keto, a diet with a high fat, moderate protein, low carbohydrate formula.

See, upping your consumption of protein and fat while drastically reducing your carb intake puts your body into a metabolic state called ketosis.

The science behind ketosis is *slightly* more complicated than figuring out the percent of calories from fat, but basically it means your body doesn’t have enough glucose (or blood sugar) for energy.

Instead, your body burns stored fat for fuel, which stimulates weight loss. (It also turns fat into ketones, which supply energy to your brain — more on that later.)

Your social feeds may be flooded with #keto posts, but the diet isn’t just another Instagram fad (or #ad).

In fact, 20-plus studies have shown it can help you lose weight and even improve your health. Research has even found that the ketogenic diet can be more effective for weight loss than low fat diets.

Keto isn’t a new concept — it’s actually similar to low carb diets of yore, like Atkins.

If that reference gives you pause, fear not: For the most part, there’s no calorie counting or food tracking involved. And since the diet is protein heavy, participants usually shed pounds without the hangry vibes.

More than a weight loss method

Eating keto can have positive health effects beyond weight loss, including lowering your triglyceride level and increasing your HDL cholesterol (that’s the good kind!).

The diet was originally used to help treat neurological disorders like epilepsy. Today, researchers are still exploring how it could help with the following health conditions:

  • diabetes
  • Alzheimer’s disease
  • cancer
  • Parkinson’s disease
  • heart disease
  • polycystic ovary syndrome
  • brain injuries
  • acne

Customize your ratio

Not to complicate things, but there are a few different forms of the keto diet

Types of keto diets:

  • Standard ketogenic diet (SKD): The most common variation, this diet typically includes 75% fat, 20% protein, and 5% carbs.
  • Cyclical ketogenic diet (CKD): As the name implies, this version involves periods of high carb consumption (like 5 keto days and 2 high carb days).
  • Targeted ketogenic diet (TKD): This diet allows you to incorporate carbs around your workouts.
  • High protein ketogenic diet: This variation has a high protein ratio, like 60% fat, 35% protein, and 5% carbs.
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The cyclical and targeted keto diets are more advanced and are primarily used by bodybuilders and athletes. The standard keto diet is the most researched method (and the most recommended).

Some diets are highly scientific. All are highly personal.

Just because a method is trending on Instagram or showing up on the New York Times best-seller list doesn’t necessarily mean it’s right for everyone. Finding a diet that fits your lifestyle and helps you feel your best can require some exploration.

Research is a good first step in determining whether a diet might fit your needs. But in some cases, firsthand accounts can be more telling. Read on for six very different experiences with the keto diet.

“Keto was a life changing diet for me”

Liz, 34, homemaker

Why did you start keto?

I was overweight and wanted to lose weight, like most people. I was also having issues with high blood pressure and didn’t want to be on medication forever.

A friend told me about the keto diet, and it looked like the few things I wanted to change in my life, it could do. So I figured that before going to a doctor and going on medication, I should give the diet a chance.

How long did you follow the diet?

Three and a half years — eating keto is still my primary way of eating.

What works for you?

These days I can get by with eating extra carbs and still stay in ketosis. I eat closer to 30 net carbs, but starting out at 15 carbs worked well for me.

What hasn’t worked?

Overeating on fat and calories, which I found was fairly easy for me to do.

Did you experience any side effects?

I had major keto flu issues starting out. I’ve since learned how to avoid it, but when I began 3 years ago, resources and info were lacking.

What do you wish you’d known in the beginning?

There’s a lot of keto junk out there, so buyer beware. Also, how to avoid keto flu. But I did what I felt was a good amount of research starting out, so I felt like I had a good idea of what to expect.

Favorite keto recipe

Egg roll in a bowl and wings. I also make a killer keto friendly pho with zoodles.

The bottom line

Keto was a life changing diet for me. It was something I really needed for my overall health — not just physical but mental as well. I heard someone say, “the best diet is the one you can stick to.” I’m a pretty firm believer in that.

“I wish I had more knowledge about diet culture”

Christal, 29 (25 when on keto), editor

Why did you start keto?

I thought I was fat and needed to be “fit” to be attractive. I discovered keto on r/reddit and was convinced it was the healthiest way to lose weight.

I also convinced myself that because my dad had diabetes, it would be a preventive lifestyle (despite my not being large or heavy in any way).

How long did you follow the diet?

Three months at first, and then 5 additional months.

What worked for you?

Making a spreadsheet and creating my own recipes so I was in charge of the portion size. I made a “what to eat each day and when” spreadsheet and set a timer to remind myself to eat snacks.

It was also a very cheap and efficient way to cook. After the initial hump, my sugar cravings dropped. Thanks to keto, I’m more aware of what’s in my food. Was it worth it? Meh.

What didn’t work for you?

I got really fit and skinny. I looked great, but it didn’t change anything other than my body, which I realized wasn’t a source of happiness for me.

I hated not being able to eat freely, and I had to explain to everyone over and over about this new “diet” I was trying while they looked at me like I was unhinged.

It would make sense if keto was a prescribed diet or if I had allergies, but I was being an unnecessary burden for no other reason than my own physical insecurities.

Did you experience any side effects?

I lost a cup size in my bra.

What do you wish you’d known in the beginning?

I wish I had more knowledge about diet culture and intuitive eating. I understand keto for people who have conditions, but for me — I’m someone who is perfectly average and normal, who can eat freely and just go to the gym twice a week and be fine.

I just did my yearly wellness check and I’m very healthy. I haven’t been on keto and I’ve been eating whatever I want (intuitively)!

Favorite keto recipe

I loved buying chicken thighs with skin and then taking the skin off to bake into chips with cheese on top. I’d also make Parmesan chips.

The bottom line

I can eat all of that without being on keto!

“It’s more complicated than that for a type 1 diabetic”

Nathan, 29, physical therapist assistant

Why did you start keto?

In hopes it would improve my health. I have type 1 diabetes.

How long did you follow the diet?

Six months.

What worked for you?

I found that I needed smaller insulin doses for my meals — at least initially.

What didn’t work for you?

My A1C (blood glucose average) score rose, and my bad cholesterol went up.

Did you experience any side effects?

Keto breath, and my LDL levels rose.

What do you wish you’d known in the beginning?

That the body can turn excess proteins into sugars if you have too much of them.

Favorite keto recipe

Lupini beans.

The bottom line

I filled my diet with too much protein, and my body was slow to convert the excess protein into sugars. This, in turn, raised my blood glucose levels higher than normal in an insidious way — I couldn’t easily detect the change or correct it.

I also didn’t focus enough on good fats and treated [the diet] as a bit of an excuse to eat fatty meats that were high in bad cholesterol. Avoiding carbs was easy for me, but it’s more complicated than that for a type 1 diabetic.

“I feel better than I have in years”

Carrie, 30, computer programmer

Why did you start keto?

Partially for weight loss but mainly to help decrease chronic inflammation.

How long did you follow the diet?

One year (and counting).

What worked for you?

I was able to get off a medication that I used for chronic inflammation, and I reached my goal weight.

What didn’t work for you?

It’s difficult to find a satisfying variety of meals because I’m a vegetarian and have food allergies, but overall it’s worth it.

Did you experience any side effects?

Slight hair loss, but not significant enough for others to notice. I added a collagen booster to my protein shakes, and it helped.

What do you wish you’d known in the beginning?

It would’ve been nice to have a carb-manager app for counting macros when I first started. And I wish I’d had a better understanding about carbs being a daily limit, protein being a daily goal, and fat being something you consume until you feel full.

Favorite keto recipe

Fathead Dough recipes.

The bottom line

This “way of life” is not for everyone. It’s a very limiting diet, especially for a vegetarian, and it takes away the opportunity to eat at the majority of restaurants (although this is improving).

It works for me — I feel better than I have in years and have found some great meals that work for me. I still enjoy a cheat meal every once in a while, though.

“[I] feel like I have six-pack abs all day long”

Mandy, 32, editor

Why did you start keto?

I wanted to drop a little weight quickly to improve my speed for a marathon.

How long did you follow the diet?

I’m currently still on keto. So far I’ve made it 4 weeks out of my goal of 10 weeks.

What worked for you?

I immediately dropped a few pounds, even though it’s probably just from water retention.

What has impressed me the most is how great I feel. I generally eat a healthy diet and stay away from refined sugars and processed carbs, but even still, restricting my intake of carbs from fruit and protein powders has left me feeling amazing.

What didn’t work for you?

My VO2 max and energy totally crashed after the first week. I went from strong 20-mile training runs to feeling like I could barely run 3 miles. I was also super hangry. This subsided after the first 2 weeks.

Did you experience any side effects?

My endurance exercise really crashed for a while, and I’m still trying to recover as my body becomes more efficient at burning fat for fuel.

The “keto flu” also took me over the first week. I wasn’t exactly hungry, I just felt really lethargic, short-tempered, and had a lot of brain fog, making it hard to concentrate.

What do you wish you’d known in the beginning?

That endurance running and high impact interval training would be pretty much a no-go for a few weeks.

Favorite keto recipe

Keto porridge. It consists of almond flour, flaxseed meal, an egg, a little bit of pumpkin purée, pumpkin spice seasoning, vanilla extract, and stevia. It helps me feel like I’m not totally missing out on PSL season.

The bottom line

It works. I’m dropping weight, don’t feel hungry anymore, and feel like I have six-pack abs all day long. My endurance still isn’t back to what it was, but that seems minor now compared to how great my stomach feels.

“[T]here’s nothing magical about being in ketosis specifically”

Coleman, 30, product designer, author, and blogger

Why did you start keto?

I started keto out of a desire for performance — I’d heard from a number of places in the sort of “high performance tech bro” sphere (think Tim Ferriss, Dave Asprey) around the cognitive and energy management benefits of adopting a low or very low carb diet.

If folks like Asprey are to be believed, there’s some neurochemical magic to a brain that runs on ketones that promotes greater focus, more consistent energy, and the like.

How long did you follow the diet?

I decided I’d give it a month of strict keto (very low carb, moderate protein), using blood testing to keep myself at 1.0 millimoles per liter BHB or greater. [BHB stands for beta-hydroxybutyrate, which is a type of ketone.] It was fine.

While I didn’t feel much different cognitively, I did have more… ”even” energy throughout the day — no post-lunch slump, primarily — and if it weren’t for the strictness of the diet and the relative difficulty it caused for someone like me who travels a lot for work and therefore eats out quite a bit, I could have happily done it for a long time.

My base assumption after the initial month was that the “more consistent energy” thing was mostly happening because of lower and less spiky blood glucose. So, after the initial month, I began titrating my carbs up and keeping fiber high to see if it was ketosis or just low glycemic response that was making me better after meals.

Turns out, the ketones had nothing to do with it. Now, several years after that initial experiment, I still average something like 50 to 100 grams of net carbs a day, above the “keto optimal” zone but still pretty low carb as compared to the standard American diet.

What worked for you?

Even though it’s sometimes challenging to find food, a ketogenic diet does make food choice really easy. Does it have carbs? Don’t eat it. Otherwise, don’t worry about it.

If you’re also trying to keep protein below a certain threshold (necessary to get into deep nutritional ketosis without supplementing ketone powders or precursors like MCT oil), it gets harder. But broadly, simple rules make for easy adherence.

I also found that as someone who doesn’t have much of a sweet tooth anyway, I find fattier foods a lot more satisfying than leaner or even carby ones. The stuff I couldn’t have on this diet seemed like less of a loss than the inability to eat a steak [would be].

What didn’t work for you?

I now understand why keto is an effective weight loss diet for a lot of people. Even if you’re eating as much bacon and cheese and all the rest as you can, it’s difficult to eat enough calories to maintain your body weight.

Did you experience any side effects?

I experienced the classic “keto flu” symptoms for a couple of days, but once I started consuming supplemental electrolytes (sodium, potassium, magnesium, zinc) and drinking extra water, I felt right as rain.

What do you wish you’d known in the beginning?

I did an absolutely excessive amount of research before trying it, so I went into it with pretty open eyes.

The only thing that I didn’t realize was how it would impact my perceived exertion for glycolytic-type exercise — circuits, sprints, and lifting. Even though my performance didn’t really suffer, it subjectively felt way, way harder.

Favorite keto recipe

Steak and eggs, cooked in butter. I never really believed in the “keto sweets” or “fat bomb” type stuff, because it always seemed like so much work for something that was supposed to be simple.

The bottom line

Even as a fairly active person, I don’t need nearly as many carbs as “standard” wisdom might dictate (and in fact feel better keeping this number fairly low).

And there are definite metabolic benefits to not being on a constant cycle of needing carbs every few hours (which is the same logic behind things like 16:8 intermittent fasting, the Zone diet, and so much more).

But at the same time, there’s nothing magical about being in ketosis, specifically.

I’ve done quite a bit of reading around the ketogenic diet for specific goals — for mitigating metabolism, for mitochondrial health, for epilepsy, as a way to make transitioning into fasting easier, etc. And I think it makes a lot of sense for people with those goals or conditions.

I also think it makes sense as a weight loss diet for people who have trouble with moderation (I would include myself in that group), because it’s so easy to understand what is and isn’t allowed.

Like strict Paleo and Whole 30 and any other number of effective but hard-to-sustain diets, it encourages insulin sensitivity and is strict, which makes it easy to follow but hard to get enough calories. Ketones are a byproduct of this, not a causal agent.

But as a regular guy who wants to perform a little better at the office and in the gym, I think it’s probably overkill.

So, what should one eat while on the keto diet (besides butter)?

Whole, single-ingredient foods like meat, eggs, fish, and healthy oils are staples in most keto kitchens. You’ll also want to incorporate plenty of non-starchy vegetables and avocado into your diet (trust us, your gut will thank you).

Here are some of the essentials:

  • red meat like ham, beef, sausage, and bacon
  • chicken and turkey
  • fatty fish like tuna, salmon, trout, and mackerel
  • pastured or omega-3 eggs
  • cream and butter (go for grass-fed when possible)
  • unprocessed cheese like goat, cream, cheddar, blue, and mozzarella
  • seeds and nuts (think almonds, flaxseeds, walnuts, pumpkin seeds, and chia seeds)
  • extra-virgin olive oil, avocado oil, and coconut oil
  • avocados
  • plain Greek yogurt and cottage cheese
  • leafy greens, broccoli, cauliflower, onions, tomatoes, etc.
  • salt, pepper, herbs, and spices (for seasoning)
  • unsweetened coffee and tea (with plenty of heavy cream)

Grains, legumes, and starchy veggies are easy enough to weed out. But seemingly innocuous foods like berries can also cause your carbs to creep up.

Eliminate or reduce your intake of the following:

  • sugary foods like soft drinks, fruit juice, smoothies, and candy
  • bread, rice, pasta, cereal, and other wheat-based foods
  • all fruit (except for small portions of berries)
  • beans and legumes (including chickpeas)
  • potatoes, sweet potatoes, carrots, and parsnips
  • low fat, sugar-free, and diet products (these are highly processed and often high in carbs)
  • condiments and sauces
  • unhealthy fats like processed vegetable oils
  • alcohol

While the keto diet can have plenty of positive effects, it also comes with some less-than-pleasant ones.

The keto flu is real (and aptly named)

Here’s the deal: As your body adapts to the diet, you may experience side effects like nausea, headaches, weakness, fatigue, muscle cramps, and constipation or diarrhea.

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The good news? This period is usually over within a few days. You can minimize flu-like symptoms by starting with a regular low carb diet for the first few weeks. (This helps teach your body to burn more fat before you completely eliminate carbs.)

Staying hydrated is always important, but watch your water intake more closely when you start eating keto. During the transition, your body will likely shed much of its stored water as it breaks down glycogen — aka carb storage units — in your muscles and liver.

Since you’re losing water, you’ll also need to replenish your electrolytes. Pass on the banana or Gatorade and instead opt for potassium- and magnesium-rich foods like salmon, avocado, or nuts.

Another fun possible side effect is known as keto breath. Luckily, this is typically short-lived — it often subsides as your body adjusts to your lower carb intake.

In the meantime, drink plenty of water, bump up your carbs or lower your protein intake, or chew sugar-free mints or gum (just be mindful of carbs in those).

As with any diet, meal planning can make or break your results on keto. If the idea of mapping out meals in advance sounds overwhelming, take a deep breath, pop a mint (too soon?), and read on.

This simple ketogenic menu can easily be adjusted based on your dietary needs and preferences.


  • Breakfast: Eggs and bacon with tomatoes
  • Lunch: Chicken salad with feta cheese and olive oil
  • Dinner: Salmon with asparagus cooked in butter


  • Breakfast: Egg, basil, tomato, and goat cheese omelet
  • Lunch: Peanut butter shake
  • Dinner: Meatballs with gouda cheese and vegetables


  • Breakfast: Strawberry shake
  • Lunch: Shrimp salad with avocado and olive oil
  • Dinner: Pork chops with Parmesan cheese, brussels sprouts, and a side salad


  • Breakfast: Avocado, salsa, green pepper, and onion omelet
  • Lunch: Celery sticks with salsa and guac, plus a handful of nuts
  • Dinner: Pesto-and-cream-cheese-stuffed chicken with vegetables


  • Breakfast: Sugar-free yogurt with peanut butter, stevia, and cocoa powder
  • Lunch: Beef stir-fry cooked in coconut oil with vegetables
  • Dinner: Bunless burger with bacon, egg, and cheese


  • Breakfast: Ham and cheese omelet with veggies
  • Lunch: Ham and cheese slices with nuts
  • Dinner: White fish, egg, and spinach cooked in coconut oil


  • Breakfast: Fried eggs with mushrooms and bacon
  • Lunch: Burger with cheese, salsa, and guacamole
  • Dinner: Steak and eggs with a side salad

Lowering your carb intake can cause your water — and, as a result, your mineral balance — to shift. Taking sodium, potassium, and magnesium in the form of a mineral supplement is a simple fix, but check with your doctor first.

If you’re eating keto and exercising regularly, the following supplements may benefit you:

  • MCT oil: A favorite of bodybuilders, MCT oil can boost energy and help increase ketone levels. Try adding it to yogurt and drinks.
  • Exogenous ketones: This kind of supplement helps raise your ketone levels, speeding up ketosis and minimizing the side effects of the transition phase.
  • Creatine: Research has shown that creatine can improve muscle mass and performance.
  • Whey: Up your protein intake by adding whey protein to shakes and yogurt. You can find whey in most grocery stores and pharmacies, as well as online.
  • Caffeine: Besides improving brain function, caffeine can also help with endurance and performance.
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1. So, what’s the deal with ketones?

When your body enters ketosis, it burns fat for fuel. It also turns fat into ketones. Ketones are molecules that supply your brain with energy.

Your brain’s main source of energy is usually glucose. But if your glucose and insulin levels are low — like when you’ve lowered your carb intake — your body will use ketones as brain fuel instead.

2. I lift, bro. Will I lose muscle mass?

Any diet may lead to loss of muscle, but keto’s high protein intake may help minimize the losses (especially if you lift weights).

3. Will I be able to build muscle, bro?

Yes, but keto may not be as effective for muscle building as a moderate carb diet. For more info on keto and exercise performance, read this article.

4. What if I’m too weak or fatigued to lift, bro?!

If you’re feeling tired, you may not be in full ketosis or utilizing fats efficiently. Try lowering your carb intake; supplements like MCT oil or exogenous ketones may help too.

5. How much protein is too much?

Too much protein can cause your insulin levels to spike and ketones to lower. Typically, no more than 35 percent of your calorie intake should come from protein.

6. What will happen if I overload on carbs?

It takes 30 to 60 days for your body to fully adapt to using fat for fuel instead of sugar. If you up your carb intake before that, you could cycle out of ketosis and get hit with those keto flu symptoms.

After that period, you can enjoy carbs on special occasions, as long as you return to the diet immediately after.

7. TMI, but my urine smells fruity.

No worries — it’s just your body excreting byproducts created during ketosis.

8. I need to drop off some timber, but…

This side effect usually passes after 3 to 4 weeks, but if it persists, try eating more high fiber veggies. Magnesium supplements also help with constipation.

The ketogenic diet is a relatively simple, well-studied weight loss method with other health benefits. But you should check with a doctor or nutritionist before starting it (or any other diet) and before adding any supplements to your diet.

Though the keto diet has been pretty well researched, the jury’s still out on staying in ketosis for extended periods of time. If you’re hoping to make eating keto a long-term change, consider meeting with a dietitian for help filling in any nutritional gaps.