It’s one of the hottest diet trends of the moment and it’s an intriguing approach to weight loss: the ketogenic diet, or as some like to say "keto".

What is Keto?

Your body can use two things to fuel daily functions: carbohydrates or fats. Carbohydrates are the preferred source of fuel for the body because carbs are the easiest to convert to energy. This is good because eating carbs can fuel great workouts, aid in recovery, or give you a quick burst of energy. However, because the body can so easily convert carbs to energy, overeating carbs (especially the “crap carbs” that most Americans eat) is also one of the fastest ways to gain fat.

The ketogenic diet is based on getting your body into the state of ketosis where your body uses fat for fuel instead of carbohydrates. When you “go keto”, you essentially starve your body of its preferred fuel source (carbs/glucose), so it is forced to rely on something else: fat/ketones.

Once in full ketosis, your body “learns” to use the fat that you eat and the fat on your body as a source of fuel. Even very lean people have thousands of calories worth of stored intramuscular fat, so this fuel source is nearly limitless.

Sounds great, right? Here’s what you need to remember: our bodies evolved the ability to go into ketosis to survive in times of famine. Ketosis is your body’s response to starvation - an extreme state of being that the body does not prefer as a long-term strategy for survival!

What is Keto: The Basic Keto Diet

Everyone’s body is unique, so before we get into numbers it’s important to understand that one person may be able to reach and maintain ketosis while limiting carbs to 50 grams per day or less, while another has to limit carbs to 20 grams per day to maintain ketosis. The only way to really know whether you are truly in ketosis is to test your blood, breath, or urine regularly.

In general, a keto diet is high in fat, moderate or low in protein, and extremely low in carbohydrates:

Percentage of daily calories from fat: 75%
Percentage of daily calories from protein: 20%
Percentage of daily calories from carbs: 5% or less

For comparison, the average American diet looks like this:

Percentage of daily calories from fat: 20%
Percentage of daily calories from protein: 20%
Percentage of daily calories from carbs: 60% (mostly coming from packaged and processed junk)

Doing the ketogenic diet correctly takes lots of planning and cooking!

Pros of the Ketogenic Diet

The ketogenic diet may work for weight loss. But it works better for some than others, and genetic factors may play a role in how well your body handles keto, and also whether or not it’s truly healthy for you. For an in-depth discussion about keto and why there is no single diet that’s best for every person, check out Ben Greenfield’s What Should I Eat podcast.

There’s so much variability in results from person to person because we are all genetically unique. Keto tends to work better for men than for women. For some people, going keto lowers their cholesterol. For others, it raises it. For some, keto reduces risk of a heart attack. For others it raises it. Some people develop gallstones from eating a high-fat ketogenic diet.

So as you look through the list of pros, keep in mind that we are all individuals. If you truly feel drawn to the ketogenic diet, go ahead and experiment! Just don’t get so invested in a single way of doing things that you ignore whether or not it’s actually working for you.

Here are what I see as the potential benefits of the keto diet:

Fast weight loss. The ketogenic diet is known for helping people, especially those with a lot of weight to lose, drop fat very quickly.
Reduced hunger and cravings. Most people report never feeling hungry once their bodies have reached a state of ketosis. This makes it easy to eat less.
Improved insulin sensitivity. The ketogenic diet is a diabetic’s dream…if you can get into and stay in ketosis, of course…more on that in the “cons”.
In some people, the ketogenic diet improves cholesterol and blood pressure.
Slowed cancer growth. Sugar feeds cancer. Since the keto diet is zero sugar and very low carbohydrate, the growth of certain types of cancers may stall.
Potential cure for epilepsy. The ketogenic diet has been used for many years to successfully control epileptic seizures.

Cons of the Ketogenic Diet

In my opinion, the biggest downfall of the ketogenic diet is how incredibly restrictive it is. Have you ever been on a diet and fallen off the wagon? Most of us have. To keep your body in the state of ketosis, you cannot fall of the wagon….not even a little….not even once.

To make keto a lifestyle you have to give up many enjoyable foods (listed below) pretty much forever. If you end up deciding that keto isn’t for you and decide to go back to your normal routine, you’ll regain any weight you lost. For keto to work you’re looking at a lifetime commitment and making very few dietary mistakes and “slips” along the way. Last time I checked, I “slip up” and fall face-first into a glass of wine and some ice cream at least once a week…bye bye keto!

More Cons of Keto

Obviously unhealthy foods like cookies and pizza are off the table, but many healthy foods are too. Beans, squashes, apples, bananas, grapes, oatmeal…even tomatoes and carrots tend to be too high in carbs and sugar for the ketogenic diet. Talk about restrictive!
If you stop doing the keto diet, or “fall off the wagon”, you will regain all the weight you lost. Keeping the weight off using any extreme diet requires a lifetime commitment to that diet.
You MUST track macros. If you think tracking calories or points is laborious, you haven’t seen anything yet.
You MUST test to be truly sure you have reached ketosis. This means daily urine, blood, or breath testing to make sure you are in and maintaining a state of ketosis. Many people claim to be able to tell when they are in ketosis, and once you’ve done it long enough, this is probably true. However, if your body is not in ketosis, you will not reap the benefits, so testing is important, especially initially.
It can take up to 2 weeks to get into the state of ketosis. During that time, most people feel pretty crappy. It’s called “keto flu”. Look it up.
Planning, prepping, and cooking are an absolute MUST! You can no longer just stop somewhere for lunch or dinner or have a few crackers in a pinch! So if you’re super busy, not very organized, or hate to cook and prep food, keto is not a great option!
Social situations, parties, and eating out take on a whole new level of anxiety because you absolutely must pre-plan for those situations or risk being forced out of ketosis. This often means bringing your own food to family BBQ's and skipping the cake and ice cream at your daughter's birthday party.
Keto is boring. The list of foods you CAN’T have is far longer than the list of ones that you CAN have. Once people reach ketosis, most of them are so afraid to eat anything that will drop them out, that they just eat the same foods over and over to be “safe”. Just like any other diet, there are plenty of recipes online that can make things more interesting…but it still means you have to get in the kitchen and actually cook.
Here’s the list of foods you CAN’T have on the keto diet: anything with sugar in it: soda, juice, cake, ice cream, candy, cookies, and pretty much anything processed in a factory or that comes in a package; natural sugars: honey, agave, cane, molasses, maple syrup; grains and starches: pasta, bread, potatoes, rice, oats, barley, quinoa, beans, corn, peas and other legumes, etc.; starchy vegetables: carrots, potatoes, beets, parsnips, etc.; most fruit: some people can eat small amounts of berries…but to stay “safely” in ketosis, let’s just say no fruit of any kind; high-carb dairy: milk, yogurt, cottage cheese, etc.; alcohol: wine, beer, mixed drinks; condiments and sauces: ketchup, BBQ sauce, many mustards, teriyaki, dry rubs and spice blends made with sugar, etc.
Being in ketosis for long periods of time may be detrimental to female hormonal health. Female hormones are extremely sensitive to stress, and being without carbohydrates for long periods of time, especially if exercising intensely, can do more harm than good for women.
If you do not metabolize fat well (i.e. you have a gallbladder issue or no gallbladder), keto can make you very sick because it’s a high-fat diet.
Keto can cause gallstones and kidney stones.
The ketogenic diet can exacerbate some eating disorders. The extremely restrictive nature of the ketogenic diet can cause binges. I have experienced this personally.
You may become nutrient deficient. The keto diet limits and excludes so many healthy foods like fruits and vegetables that you may not get all the vitamins and minerals you need.
Sorry darling, but eating bacon, butter, and cheese is NOT a healthy diet. Keto can be taken out of context and can absolutely be done wrong! A doctor or dietitian’s supervision is absolutely necessary when undertaking keto!
The diet is very low in fiber, which may cause digestive problems for some.
For some, the keto diet increases cholesterol and triglycerides.
It’s not a vegetarian- or vegan-friendly diet.
It’s expensive. Not only is it expensive to buy high-quality meats and fats, but you’ll likely need to take supplements because the keto diet often leaves people deficient in important nutrients.
Did I mention that you must eliminate pizza, donuts, pie, pasta, cake, bread, wine, beer, and BBQ sauce? Forever. Is that a commitment you’re willing to make?

I hope you don’t like pizza…because you can’t have it on keto!

The Bottom Line on Keto

Each of us is a unique individual with unique needs. If there was one diet that worked for all people, we'd all be on it, and we'd all be lean and healthy. The unfortunate truth is that, despite the existence of all these diets and all the information to which we have access, the diets don’t seem to be helping us! Those who are successful at lowering their body weight and keeping the pounds off are doing so through a more moderate approach to eating and a focus on health - not body size or appearance!

Do you need help figuring out why your body is retaining excess unwanted pounds? Contact me for a consultation!

Blog Author: Kelly Bailey, IIN certified holistic nutrition coach, and NPTI certified personal trainer

Learn more about the author here.

What is KETO?