It’s been a while since I last wrote about keto, so I figured that it’s a good time for an updated keto diet review, since this diet is still wildly popular.

When someone comes to me and asks me if they should try a particular diet or eating plan, the first thing I assess is whether or not it’s a plan that’s physically or emotionally dangerous. The second thing I look at is whether or not it’s sustainable. Because really, those are the things that really matter the most: is it going to hurt you, and are you going to be able to stick with it for more than three days.

I guess we should throw in ‘why are you going on a diet in the first place?’, but that’s a whole other post (and my book, Good Food, Bad Diet)

A lot of people believe that because I’m a dietitian, I’m automatically against low-carb diets. That’s completely false! I’m pro any way of eating that makes you happy and healthy. 

What is Ketosis?

Ketosis is a state that your body goes into when it doesn’t get enough carbohydrate, either because you’re starving or, because you’re intentionally restricting carbs. 

The body’s first line for fuel is carbohydrate that it breaks down into glucose. When carbs are scarce, our bodies are adapted to break down fat for fuel so we don’t starve to death. 

To do this, the body starts a process called ketogenesis – essentially meaning ‘the making of ketones’, during which the liver converts fat to ketones. These ketones are used by your body as fuel instead of glucose, and this is how the ketogenic diet works: using fat for energy. 

We aren’t really sure how people end up losing weight on the ketogenic diet, but it could be multifactorial: likely because ultra-processed food isn’t allowed, so there goes that. Also, a diet that’s mostly fat is extremely satiating, so you’re not snacking every half hour, and your calorie intake naturally decreases, leading to weight loss.

Insulin levels drop when we don’t consume carbs, which some people believe helps us burn fat. This carbohydrate insulin hypothesis is just that – a hypothesis – and hasn’t been definitively proven by research (and here). 

We can’t talk about the ketogenic diet without mentioning DIETFITS, which was published in February, 2018. This year-long, comprehensive (and very well done, I might add) study pitted low carb and low fat diets against each other to prove various hypotheses. Click on the link if you want to see the study and its methodology, including carb and fat levels at each stage.

As always, my fave site has the best synopsis of the study I’ve read to date (here)

Here’s what the study found:

1. As far as the insulin-carbohydrate theory, DIETFITS found that insulin levels did not affect weight loss. And even though it was funded by a low-carb group, the study proceeded to poke major holes in their insulin theory. Ooops! 

2. For which diet caused more weight loss, DIETFITS found that while the low carb group lost more weight initially, the whole thing evened out over the course of the year, ending up with both groups within two pounds of each other. 

3. The best diet is the diet you can stick to. 

You’ll probably lose weight initially on the keto diet because you’re dumping glycogen, which binds several times its weight in water. Once all that water is gone, you’ll be down a few pounds, which can be inspiring.

The hard work begins when you achieve ketosis – usually in around 72 hours after starting the diet – and need to keep yourself there.

What is the Keto Diet?

While keto may be easy for some, it can be very challenging for most. That’s because to be in ketosis, you need to eat around 75+% of your calories from fat. That’s a load of fat, and if you break ketosis by having a piece of bread or more than a few berries, the diet stops working and the weight you lost becomes a sweet memory.

The level of carbohydrate that each person can eat and still be in ketosis varies – some people can’t eat more than 20 grams a day; some people can eat 50. It’s still going to be a hell of a lot fewer carbs than you’re probably used to eating on your normal diet.

The keto diet isn’t high-protein, and in fact, too much protein may kick you out of ketosis, so it’s not as though you’re going to be mowing your way through piles of steaks and meatballs all day long. 

What does a Keto Diet Look Like?

The keto diet macros look something like this:

Of total daily calories:

Fat: 75+%

Protein: ~15%

Carbs: ~5%

A typical day on the keto diet looks like this. 

Breakfast: Coffee with grass-fed butter and MCT oil, or eggs fried in butter with greens.

Lunch: Big salad made with greens and avocado, plus salmon or another sort of protein.

Dinner: Steak with asparagus.

Snacks: Nuts, seeds, cheese and vegetables, meat jerky.

There’s also what is aptly called the ‘dirty keto’ diet, which is comprised of low-carb fast and ultra-processed food. I’m not sure why anyone would want to eat this food three times a day, and I definitely don’t recommend this version of the diet simply due to its high levels of unhealthy fats. 

If you don’t reach your daily fat quota, there are ‘fat bombs’ comprised mostly of things like coconut oil, sweetener, and unsweetened chocolate to help you…sort of like a keto sweet of sorts. 

The meal plan above doesn’t seem too bad, does it? I mean, it’s mostly whole foods, and it includes lots of things that most of you probably love, like steak and cheese. 

Not allowed are dairy except for butter and cream; most fruits, legumes like chickpeas and lentils, breads, pasta, potatoes, real pizza crust, any sweets that aren’t keto, etc. You have to work hard to make sure that you’re getting adequate fiber in your diet, since many fiber-rich foods are off the table with this diet.

The issue comes when you start to want birthday cake on your birthday…or in the summer, when the peaches are ripe…or when you go out with friends and want a few glasses of wine…or when it’s pizza night…you get what I’m talking about. Are you going to be able to eat this diet and still feel fulfilled in other areas of your life? Think carefully.

As far as plant-based keto, it can be done, but it entails a shitload of nuts, some tofu, seitan, and protein powder. 

This panfried prosciutto is definitely a keto-friendly food!

Ketogenic Claims: Weight Loss and a Cure for Cancer?

The ketogenic diet has been used for years to treat people with epilepsy, in particular children.

It has only recently been discovered as a weight-loss diet, and there are other, more dubious claims for it as well, including that it prevents aging, ‘burns fat forever’, and effectively cures cancer and diabetes.

None of these are true, and the last two are just egregious. If you have type two diabetes, a low-carb diet may help lower your blood sugars, but it won’t put the disease into remission, since that would mean that you wouldn’t have diabetes even if you went off the ketogenic diet.

Nothing cures type one diabetes except for a pancreatic transplant, that’s that. 

The fat burning claim is a vastly overplayed dud; While ketogenic diets burn fat for fuel, they’re not proven to do so in the long term any more efficiently than low-calorie diets. If you’ve read my blog, you’ll know how I feel about ‘fat burning’ claims. Spoiler: I can’t stand them.

To say that a diet cures cancer is untrue and potentially harmful. If a cancer patient is convinced to try a diet or any ‘alternative’ treatment instead of chemo, studies show they have a decreased chance of survival. If they’re on chemo and also on a keto diet, the changes in blood work that may occur from the diet may prevent them from continuing on with their chemo, creating a dire situation in which they have to stop treatment until their blood work corrects itself. 

No diet cures cancer. No diet has EVER cured cancer. 

While we all sincerely wish this was the case, it’s unfortunately not. And no, I’m not ‘in the pocket of Big Pharma’.

In terms of exercise, regardless of what the people at your Crossfit box say, research lands squarely in the ‘carbs for fuel’ camp. (and here) Meaning, the keto diet probably does not improve most peoples’ exercise performance. In cases that it does, the athletes must be keto-adapted for several months before they see the benefits.

Losing weight on a ketogenic diet can also make exercise easier for some people, which can improve performance. 

There is emerging research for the ketogenic diet and brain cancer – not as a cure, mind you, and neurological diseases such as MS and Parkinson’s disease, as well as IBS and IBD. Many of of the studies done on disease and keto have only been done on animals, and many are small or single studies, so when I say that the research is ‘emerging’, that doesn’t mean ‘believe it like it’s gospel’.

It means, ‘more studies – big, human, and well-designed studies – are required’. But right now, there is some positive research coming out about keto being an adjunct to brain cancer therapy.

In terms of the resolution of IBS symptoms on the keto diet, it may very well be the elimination of fermentable carbohydrates, called FODMAPS, that is responsible for this outcome. 

Love peaches? Sorry, not allowed on keto.

Fat loss is I believe one of the most common reasons why people would choose a ketogenic diet, but because it’s so difficult to follow, and because it doesn’t work for everyone, it’s tough for me to make a blanket recommendation for this diet. But that’s not big news: I’ll never make a blanket recommendation for any diet. Why would I ever do that? You’re all different, and my job is recommending different things for different people.

That’s because I want to make sure that each individual eats in a way that works for them. 

There are hundreds of doctors, dietitians, and other professionals who recommend nothing but keto for everyone. I take issue with anyone in a position of trust who pushes one particular diet on every single person, because that behaviour completely disregards peoples’ unique preferences, lifestyles, and health histories.

Our jobs as professionals is to take all of that into account before recommending any particular eating plan. *end rant*

Like most things in life, with the keto diet, there are benefits and drawbacks.

The Benefits of the Keto Diet

Your blood lipids and blood sugars might improve. There is some evidence that harmful blood cholesterol levels may decrease with a ketogenic diet, but this doesn’t happen with everyone. In fact, some people on keto may experience higher cholesterol levels. As far as blood sugars, a ketogenic diet may help manage glucose levels.

You’ll most likely lose weight. Not everybody loses weight on a ketogenic diet, but many do. 

Some people report feeling an increased sense of wellbeing and more energy.

Unless you’re doing the ‘dirty keto’, you’ll be cutting out most ultra-processed foods. This is great! You might have to plan ahead in some situations – ie holidays and vacations, but forcing you to eat fewer ultra-processed foods is a definitely plus for keto.

The Downsides of the Keto Diet

It can be expensive. Buying a ton of animal protein and avoiding cheaper proteins can be costly. 

It can be socially isolating. It can be hard to navigate social occasions when you’re following keto and can’t eat a lot of what everyone else is eating…unless they’re also doing keto. Most of the time, making meals keto is an easy fix, but think of how it will make you feel to have to make those adjustments in different situations.

It can make you feel terrible. Keto flu, lack of energy, mood swings from no carbs…we all react differently, and some of these things disappear after a week or two, but sometimes not.

Sweeteners can make you fart. Keto relies a lot on sugar alcohols as sweeteners, and they can cause major gastro distress. The diet can also cause constipation and bad breath.

It can make your bad cholesterol levels rise. Just as cholesterol levels decrease in some people, some people have the opposite effect.

You can’t go on and off the diet – you must stick to it religiously. 

Saturated fats are still not healthy. There are plenty of people on the internet saying that saturated fats are healthy. Some of them even claim that olive oil is harmful. 

These people are wrong. If you do keto, make most of your fats the healthier type – avocado, nuts, and olive oil. 

It’s very limited. You can’t have most dairy, or bread, legumes, sweets, fruit, am I missing something? You get the point. 

It’s tough to maintain for the long-term. 

My Final Thoughts on the Keto Diet

The ketogenic diet may help some people lose weight and control their blood sugars, but it’s extremely restrictive, and it’s definitely not a ‘cure’ for disease. 

If you stray from the diet, you’ll gain the weight back fairly quickly. This can lead to weight cycling, which can be emotionally tough. Yo-yo dieting isn’t fun.

As with every diet, consider the cost benefit (read about it here). Emotionally, socially, financially, and physically – what is this diet going to cost you? Is it worth it? Can you deal with these costs for the long-term, especially knowing that the ‘benefits’ disappear as soon as you go off the diet? Is it going to destroy your relationship with food? How is counting carbs to the last gram – even in ‘healthy’ foods like vegetables – going to affect you?

These are valuable questions that you should be asking yourself.

And when you’re researching keto or any other diet online, please remember that n=1 doesn’t mean a hell of a lot. Even lots of n=1s doesn’t equal science…it just equals a lot of people who are telling you what you want to hear.

It’s easy to find favourable anecdotes about keto, but we don’t often hear from the people who aren’t successful on it or other diets. That’s because many people who fail at diets may feel shame at disclosing that.

Just so you know, I believe that there are far, far, more people who have failed at keto (and every other diet) than there are people who have managed to maintain this way of eating for over 5 years. Be objective, thorough, and realistic when you’re doing research on any eating plan.

Don’t just blindly jump into it telling yourself you’ll ‘make it work’; measure it against your particular lifestyle, preferences, financials, etc. 

And lastly, remember: If keto isn’t for you but you still want to try a low-carb diet, go ahead and do it! If you’re currently eating a high-carb, high ultra-processed food diet, you don’t necessarily have to go all the way into a keto diet in order to reduce carbs. Something with a bit higher level of (healthy) carbs might be more sustainable for you long-term, and whole lot more enjoyable. 


  1. I think extreme diets appeal to serial dieters in the “this is my last chance” mindset, but they are not sustainable for life. If I had a lot of weight to lose, it might sound sensible to lose the weight on an extreme diet, then transition into another way of eating. But from what I’ve seen, most simply “transition” right back to the crappy way of eating they’d been doing. I think I’d rather just lose the weight, perhaps more slowly, by gradually making lifestyle changes that I would follow for the rest of my life.

  2. My partner and I have both failed at Keto! Like you say, there’s likely to be a whole lot more of us failures out there! It’s a miserable way to eat and fails the minute you stray from the path. Not one I’d recommend to anyone purely as a weight loss diet.

  3. Thank you for such insight on this Keto diet thing. I work with several people who claim to be on this diet and then fall off of it on the weekends. Very interesting to read that you must be faithful the whole time. I am printing a copy of this article and placing it on their desks. I enjoy reading your articles.

    1. I think, like anything printing off this article and telling the people you’re working with that they can’t indulge on the weekend so don’t try keto is just making it harder for them. I think the big picture and seeing that 5days per week if they make progress and perhaps lose 3-4pounds, but their weekend of pizza or pasta gains one of them back is still probably better than what they were doing before. I think the trap that many of us fall into is thinking that if we aren’t on a every dropping trajectory, that we are failing….if we get away from the “fall off”/”get back on” mentality and see the journey for what it is, and continue to have goals regardless of what happened yesterday then there can be a lot more success on this, (or any lifestyle change). For me, I have been doing Keto for nearly 2 months now…have dropped 31 pounds, and am having the time of my life (literally). There are challenges, and going to an italian restaurant last night with family and friends caused decisions to be made. Did that make me miserable? Definitely less miserable than if I went to an amusement park and couldn’t fit in the roller coaster next to my daughter. I think that the choices we made to get obese or overweight have consequences, and if we want to get healthy, sometimes we have to reverse those choices and those aren’t always super pleasant, but are necessary if we want to get healthier. I think that perhaps those who are failing at diets (including myself in the past) is that the relationship with food or the ease of finding unhealthy choices is more important than the reasons you might have to get healthy (at the moment). Im only speaking from my experience, but once the reason to get healthy is the most important thing in your mind, then it doesn’t matter what plan, diet or lifestyle you’re on….you will do what it takes. But unfortunately many people lose sight of that reason, the moment it gets hard. BEING healthy shouldn’t be hard, but GETTING healthy after years of abusing our body can’t be expected to be easy, though so many of us give up when it’s not.

  4. Would Keto be the most efficient way to try to lose a chunk of weight in the short term? I have a lot of trouble sticking to low calorie diets and I know I cannot do any strict diet long term. However, I truly just want to look better for my son’s wedding this summer so I am considering doing the Keto just until the wedding. Does that sound feasible?

  5. Excellent information Abby,thank you! If a person asked you about a low carb diet, what % of total calories would you recommend as carbohydrate?

  6. My weight is usually good. But weight crept on as I hit 60. Went on 4 week holiday and came back w added pounds. Went on keto for 3 weeks. Lost 10lbs. I started introducing some carbs but the weight continued to fall off. I’ve lost 20 lbs and have kept it off. Here’s the thing: Keto teaches you to watch those carbs. Sugar cravings are gone – can’t stand sweet. I feel great- thought this was the easiest diet ever.

  7. Keto diet definitely works very well! Here in Thailand the most simple way to try keto is just to not eat any rice. When I tried keto I had to stop after a week because I was losing too much weight too fast. I felt great but I didn’t look good. Sawadeekha ???

  8. I think anyone claiming keto “cures” cancer is misrepresenting the science. What it actually does is deprive the cancer cells of glucose making them more susceptible to dying from chemo. Dr. Valter Longo has done several studies using a low calorie ketogenic diet he calls a “fasting mimicking diet” showing improvements in chemo treatment for several different types of cancer vs using the standard American diet with the normal standard of care.

    Otherwise for the most part a good article. Few points I feel are debatable but science is still iffy when it comes to alot of keto stuff.

    1. I agree. The author says
      “No diet cures cancer. No diet has EVER cured cancer.”. Well, the question is does any diet cause cancer? We know bad eating habits, a lot of sugary food does. So any reversal of that type of diet at least would not contribute to the failure of the body. When the body gets rid of that continuing stress, it has a chance to recover.

  9. My husband and I have loved keto! Once you adjust yourself to alternatives for the things you once loved (pizza, ice cream, Etc) your taste buds change and you become accustomed to cauliflower/almond flour crust and homade ice cream. I had to up my carbs from 25/30 to 50/60 because I lift and do cardio. My husband is perfect right at 30. Wevet been on it for 6 months now and cheated on Thanksgiving and Christmas dinner. Pretty much all our friends do it and it is way easy to do meals together. I agree it’s not meant for everyone but we have absolutely enjoyed it and I don’t have to make separate meals for my kids. We all eat spaghetti (zucchini noodles) as a family. They of course don’t eat all the fat we do and have fruit and sandwiches and such but it has been great for our whole family. We don’t have so much crap food in the house. In general it’s just a good idea to not eat sugar and be aware of the carbs you take into your body. We will probably start tapering off in the next couple months but it was wonderful to slap our bodies in the face and say enough is enough, stop eating so much crap!

  10. I’m starting my 5th month on Keto. I’m 77 yrs old and have been 15 to 60 lbs overweight most of my life. Quite familiar with many, many diets I have tried, I started keto after a lot of reading about its pros and cons. I think it’s best used as a food life-style change and not a diet. Here are the benefits I’ve gained: I am RARELY hungry anymore, eating smaller amounts four to six times a day; I have lost weight but not because I weigh myself – as I don’t own a scale, but because I am down one to two clothing sizes, depending on the garment; my energy level is up and has stayed up; I no longer crave candy or ANY of the “junk” food items I’ve loved all my life. Honest. Gone is the NEED for potato chips, Doritos, fast food etc, etc. What a blessing! I exercise regularly with professional training in Kung Fu Tai Chi, dog walking and 3x week weight lifting. I know exactly what to eat at parties, restaurants, and other eating events. If I have an alcoholic beverage, I have only one. Most folks just don’t notice my eating “change”. Family and friends who know I have switched to keto either think I’m goofy or they want me to explain it so they could try it. I’m likely to say to the “expert” friends/family folk to back off when they criticize and tell them to do some research before lipping off with their judgementness. To the rest, I tell them it’s a lifestyle change for me; I like it; and recommend they go read ALL the research they can find before trying it.

  11. The Keto Diet is for the lazy people who hate rigorous exercise. 40 years ago I was a 225 lb. 42 year-old male. Through controlling my own diet (smaller portions, no processed foods) and rigorous calisthenics and running I took a year to drop down to 160 lbs. I’ve stayed between 155 lbs. and 170 lbs. thereafter. There was no conscious limiting of carbs–just total reduced calories and increase of muscle mass. The resulting higher metabolic rate burns off calories fast. I have no fear of birthday cake, pizza, ice cream or other carbo foods. It just burns off. The extremely low carb intake required by the Keto Diet robs the body of energy to carry on with a regular program of rigorous exercise. I just changed my eating habits and exercise habits for life. I’m 77 years old and have a lean muscled body weighing 155 lbs. on a 6 ft. 3 in. frame.

  12. Diet and exercise is always the way to go however I needed to lose or wanted to know 15 to 20 lb so they had the keto diet the pill that is pay shipping these only they added a cleanser to it which I didn’t ask for all I want and I guess I’m stuck because I paid for it I have already lost 97 pounds I just wanted to lose 15 to 20 more pounds I didn’t ask for anyone to come in to take money from me that’s it you had your chance

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