With the fast-growing popularity of the keto diet, we knew we had to try it for ourselves. If you’ve never heard of keto, it’s essentially a low-carb, low-protein, high-fat diet. It puts your body in a state of ketosis, where you produce ketones (from fat) to give you energy, instead of blood sugar or glucose. Basically, the diet tries to mimic being in a fasted state without actually fasting, by eating mainly fat and few carbs.

The idea is that if your body is “fat adapted” and runs off of fat (or ketones), you can avoid low and high blood sugar levels, burn body fat easier and faster, and improve athletic performance. Because while you have a limited amount of stored glucose, your fat stores are abundant. However, there is inconclusive research on these hypothesized benefits and many of the studies have small sample sizes, high dropout rates, mixed results, and know very little about the long-term effects.

The ketogenic diet closely resembles the Atkins diet, and has gathered a following of firm believers. Some love the idea of losing weight while eating bacon and butter, whereas others like the idea of improving athletic endurance. Whatever peaks your curiosity, you should know that this diet does not have enough research for me (Megan) to feel comfortable recommending it to most people. Plus, if you read our reviews, you’ll learn some pretty negative side effects that can happen after getting into ketosis.

How did the diet stack up nutritionally?

We decided to go with a clinical keto diet, instead of the popular modified Atkins diet. You might be wondering, what’s the difference? Well, a clinical keto diet is a 3:1 or 4:1 fat to carb/protein ratio. Many mistakenly think this is based on calories, but it’s actually food grams. So for a 3:1 ratio, 75% of food grams should come from fat, which translates to 87% of calories from fat.

Macro Breakdown

3 or 4 grams of fat to 1 gram carb or protein

  • 1g fat = 9 calories
  • 1g carb or protein = 4 calories

Example

A 150-pound (68 kg) woman eating 2,000 calories a day


Our Team’s Macros

  • Fat = 3:1 ratio (depending on total calories as listed above)
  • Protein = 0.8g/kg of protein (I decided to use this to ensure adequate protein)
  • Carbs = remaining non-fat grams

I worked really hard to incorporate lots of vegetables, avocados, and nuts, and to limit processed foods. But honestly, with such a restriction on protein and carbs, I still had to limit even high-fiber, low-carb vegetables, like leafy greens. This diet really was lots of olive oil, butter, and heavy whipping cream. While I focused on more unsaturated fat sources, the reality is that it’s easier to get people to drink heavy whipping cream than it is to drink olive oil.

So, let’s use Trevor for example. He was on the highest-calorie plan, with about 5 servings of vegetables a day. For his macros, his average nutritional breakdown was:

  • 3,830 calories
  • 370g fat (178g saturated)
  • 79g protein
  • 45g net carbs (22 grams fiber)

As you can see, this was not enough fiber or protein to maintain his high muscle mass. And it was nearly 300% his recommended fat intake.

Looking at his micronutrients, he was able to meet many of his vitamin needs (remember though, he was eating almost 4,000 calories a day). However, he was low on thiamine, biotin, vitamin D and folate. When it came to minerals, he was low on almost all of them, including calcium, magnesium, and zinc.

His diet would have also been low in potassium, but we provided electrolyte supplements to help with dehydration, since this was such a low-carb diet. He wasn’t low on iron, but at 11mg, it would have been too low for a female.

In general, this diet lacks in many nutrients, including protein, fiber, vitamins, and minerals. It’s also low in nutrients we don’t measure, like antioxidants and other phytochemicals found in plant food. From a nutrition standpoint, I would be very hesitant to recommend this diet, unless it was medically necessary, like for medication-resistant seizures. And I think anyone doing it should take fiber, vitamin, and mineral supplements, and drink lots of water to prevent dehydration.

Our takeaway message is:

  • The keto diet is designed to mimic fasting.
  • It’s a high-fat diet with a 3:1 or 4:1 ratio that translates to 87–90% of calories coming from fat.
  • It may help with weight loss, diabetic control, and athletic performance, but the research is inconclusive and has limitations.
  • This diet limits many healthy foods, including fruits, vegetables, whole grains, and lean protein.
  • This diet is low in many nutrients and can lead to dehydration, so if you choose to do it, make sure to take fiber, vitamin, mineral, and electrolyte supplements.

Our Team’s Quick Review

Trevor Mann—Marketing specialist, father to a stud, gym junkie, and sports fanatic

Michelle Alley—BS in nutrition, mom of 2, former collegiate runner, training for a marathon

Megan Ostler—MS, RDN, mom of 2, still breastfeeding

Alex Ipson— Iron Man, workaholic, product owner at iFit

Hannah Mann—Social media guru, busy mom, and regular gym goer

  • Keto had a positive effect on my menstruation cycle, but overall it was difficult to stick to. See my review here.

Josh Nuckles—MS in fitness promotion, father of two, cyclist, ultra runner, and iFit trainer

  • I had a rough go at it, but I think keto could have benefits for the right person. Read my review here.

 

Individual Experiences

Trevor Mann

Going into this diet, I didn’t know much. I’d heard a lot about keto from social media, but didn’t know the parameters of the diet, possible side effects, and results. I didn’t do my own research until I was a couple days in. However, before we started, our group got together and our nutritionist gave us a brief overview of the diet. She explained that we might experience certain side effects, like the keto flu or keto rash. It sounded like this was going to be a blast!

When I started the diet, I was loving every meal of it. I was eating more fat than I ever have, and enjoying all the flavors. It was odd not eating a lot of protein, but I wasn’t complaining because I was full and the fat-bomb snacks held me off until my next meal.

The first week went by and I hadn’t experienced any symptoms. No flu, no rash, not even a tingling sensation that some of the other participants had. My body was processing the fat really well! I could tell that I was losing weight, and my stomach seemed to be experiencing the biggest change, with my abs becoming more noticeable after just one week.

Initially, my workouts were a little more difficult to finish. I didn’t use any kind of supplement/pre-workout during the diet, which is usually my crutch to push me through my workouts. So the first week I was a little low on energy, but that all changed in the second week.

By week two, I was basically in keto autopilot. I was loving the food, loving the sugar-free-chocolate, heavy-cream smoothies (which was my go-to fat bomb), and I started to have more energy. It wasn’t the kind of energy you feel when taking caffeine. It seemed like a longer-lasting energy that my body could gradually draw from as needed. My workouts became easier in the sense that I could finish them with the same high-energy level I get from my supplements.

When week three rolled around, I still hadn’t experienced any of the symptoms and my ketone levels were high. Usually, 1.5 means you’re in ketosis, and I was at 4.6 in the middle of week three, so I was well into ketosis. My energy levels were up and I was losing weight, six pounds to be exact. It may not seem like a lot, but keep in mind, I was also on a 4,000-calorie plan, since I wasn’t necessarily trying to lose a lot of weight. My goal was to keep the muscle while trimming the fat, and this is exactly what happened.

Keto has been my favorite diet so far. If I can eat high calories, high fat, and lose weight, then sign me up, every time. I would recommend this diet to people looking to lose weight for medical reasons or just as a personal goal. Go into this diet with a positive attitude and do your very best to stay mentally strong. It will make all the difference!

 

Michelle Alley

I was pretty curious about keto, since several of my running buddies were performing really well on it. I was hoping maybe it would do the same for me. I knew keto was going to be rough because I don’t love butter or cream cheese. In fact, I never butter my toast or put cream cheese on a bagel. I even prefer oatmeal chocolate-chip cookies, as I often find regular chocolate-chip cookies too buttery and unappealing. So when I saw the meal plan, I was pretty nervous knowing that I was going to have to force myself to consume lots of butter and cream cheese. I ended up throwing up two of my dinners because I just couldn’t force the amount of butter and cream cheese down.

For the first couple days, I felt gross eating so much fat. I only felt good when I worked out. The first time I went for a run, I didn’t think I’d make it a mile, but I pushed on and actually felt fine, so I was pretty pleased.

However, my mental state was a mess. I was dealing with major brain fog. I would look at a recipe, go to the fridge, forget what I needed, then have to go back and check the recipe again. I’m sure it didn’t help that I was also suffering from major insomnia, which is a very common side effect when you change your diet to low carb.

After the first three days, I thought I was in the clear. I was getting used to the food, not loving it, but I could eat it without gagging. However, by the sixth day, things came to a screeching halt. I went for a run and noticed my limbs becoming severely numb. It got to the point where I physically couldn’t move my arms. I tried to call my husband Jeff, but I couldn’t raise my phone up to my ear. I let out a scream because my arm felt like it was in a state of rigor mortis.

When I finally got home, I just laid on the floor while Jeff rubbed my arms and told me I could either eat some carbs or take a trip to the hospital, where I would most likely get an IV. So I ate about 50 extra grams of carbs and felt much better. The next day, I tried to get back on keto, but by about 6:00 that night, the numbing effect was happening again to all my limbs. At this point, I decided I was done with the diet.

In good conscience, I can’t recommend this diet for the masses, but if you want to experiment with keto, I would do so cautiously. I’d highly recommend meeting with a dietitian to help you do this diet safely and find what amount of carbohydrates you can have to still be in ketosis, as this amount is different for everyone.

 

Megan Ostler

Before we started keto, I had a lot of reservations from a health standpoint, like limiting fruits and vegetables in the name of low carb. But I have friends who experienced amazing benefits, while others who have horror stories. Needless to say, it piqued my curiosity and I was ready to try it myself.

Since I am breastfeeding, I wanted to make sure I did my research. I started thinking about the breast milk composition itself, which is about 40% carbohydrates (or lactose). If I was in ketosis, would the ketones replace the lactose? What would that mean for my baby? I reached out to some neonatal health professional friends for advice. One of them, a NICU nurse, told me about the diagnosis of lactation ketoacidosis—a dangerously high accumulation of ketones in the blood that can lower blood pH, which can be fatal. I’d never heard of this before, since I thought ketoacidosis was only a problem for alcoholics and those with diabetes. But then I came across a case study about a breastfeeding mother who ended up in the ER with ketoacidosis, and she wasn’t diabetic or an alcoholic.

So while those aspects made me a little hesitant, this article (although done on rats) about lactation ketoacidosis and neonatal brain abnormalities finalized my decision to skip this diet. It just wasn’t worth the potential risk for me or my baby.

 

Alex Ipson

This was the first diet I have ever followed. I typically eat whatever I want, whenever I want. I was interested in trying keto, as I’d heard a lot about it and thought I’d give it a try. I had no idea what I was in for.

The first two days were the most difficult for me. During this time, my energy level was very low. I had a hard time focusing, critically thinking, and didn’t have much motivation. My senses felt elevated, and I was easily distracted. I tried to continue my regular workout routine, which includes cardio and strength training in the morning for 90 minutes. But I had a very difficult time making it through my workouts, as I felt low on energy and strength.

On the third day, I started to feel great. I felt clear and focused. My mood and energy level was consistent. No highs, no lows, just steady. But I still found it difficult to exercise at the same level as I was before the diet, especially lifting weights. In addition, my stomach was pretty angry with me for the entirety of the diet.  

Throughout my time on keto, I thought about food constantly, which is not typical for me. With the high-fat, low-carb, and low-protein meals, I wasn’t hungry, but I never felt full or satisfied either, which is why I think I thought about food obsessively.

I also found it very difficult to eat out at a restaurant on this diet. I couldn’t bring myself to ask a waiter to make all sorts of substitutions for me, so when I ate out on the weekend, I tried to eat what was close enough to meet the diet guidelines. Inevitably, this led me to stop the diet after two weeks, as I was going out of town for a business trip for a week.

Overall, I did experience some benefits from this diet. Specifically, I had an even energy level and mood during the day, and I found myself drinking much more water than I typically do. But in the end, this diet was not sustainable for me and I will never do it again.

 

Hannah Mann

I was the most skeptical about this diet, mostly because of all the side effects I’d heard about, but I was curious how my body would respond. On the first day, I drank my Green Cream Shake for breakfast and was instantly so full. By lunchtime, I started to feel a little woozy, but I assumed it was too early to start feeling symptoms.

The next day, I started a very heavy period, even though I thought I was on my period the week before. (I currently have an IUD and PCOS, so my periods are typically very light and irregular.) I’m not overweight, but this study shows that keto actually helped women with PCOS. With that being said, I still don’t think I would change my lifestyle to keto.

On the third day, I woke up with the keto flu. I felt terrible. I didn’t want to eat anything from my meal plan, because the thought of eating more fat was revolting, so I didn’t eat much that day. The rest of the first week was smooth sailing, though. I lost six pounds, which I couldn’t believe!

In the second week, I started experiencing numbness in my hands and feet, with my limbs falling asleep quicker in certain positions. I also wasn’t enjoying any of my meals, and for my own sanity, I would sometimes sneak one bite of something that I was uncontrollably craving.

I was about to start the third week when I got a terrible migraine. I wasn’t able to keep any food down and pain meds weren’t helping. I tried everything to make it go away, but then I caved and ate a whole batch of rolls. That did the trick and my migraine went away! I decided that my body needed carbs and it was time to be done.

 

Josh Nuckles

I’ve never been on a diet before, so this was a difficult, yet interesting experience. I have several friends that have seen notable improvements on keto, so initially, I was looking forward to trying it out and possibly experiencing some of the same improvements.

However, after about 24 hours, I felt the full wrath and fury of the dreaded keto flu. I had no energy and I was basically a zombie. In fact, several times during the day I would suddenly realize that I had been just staring out the office window for who knows how long. When co-workers asked me questions, I often had to ask them to repeat themselves, because I couldn’t quite process what they were asking, despite my attempt to focus. Things were also physically difficult. I bike to work and my ride home was usually pretty rough. The few hills that generally don’t cause a sweat transformed into laborious, challenging climbs.

After the initial shock, though, my body seemed to slowly rebound, even though my mental state remained sluggish. I was still noticeably short with my wife and children, and had a fairly high level of apathy for nearly everything in my daily life, including things I would normally be excited about. I was also surprised at how consumed I became with thoughts about food.

If you’re going to do this diet, I would highly recommend working with a nutrition professional, so they can help you incorporate the right amount of macros and micros. I would also highly recommend slowly increasing your percentage of calories from fat over the course of several weeks, in an attempt to avoid GI distress.

 

WARNING: This post is not intended to replace the advice of a medical professional. The above information should not be used to diagnose, treat, or prevent any disease or medical condition. Please consult your doctor before making any changes to your diet, sleep methods, daily activity, or fitness routine. iFit assumes no responsibility for any personal injury or damage sustained by any recommendations, opinions, or advice given in this article.