Keto: Fact or Fiction?
Updated: Aug 14, 2019
So, you all know that I love a good research review. I get asked all the time about various diets and I decided to take a harder look at the research behind (or not behind) the keto diet.
Honestly, after spending 10+ hours on this post, I think I am going to keep my research reviews to psychology topics. However, I do value this time I had to learn more about keto! If any of you dietitians out there ever want to guest post a research review, please email me! I'd love to have you!
Let's get one thing straight:
I am not a doctor or dietitian. I am a mental health therapist who treats negative body image and disordered eating. This post is basically just a compilation of all the information I have found on the internet. All of it will be linked as we go! As always, this is just for educational purposes and should not be taken as a replacement for mental health or medical treatment.
What is the keto diet?
The keto diet means you eat low carb and high fat (70%-80%). People do this in order to put their body in a state called ketosis. Ketosis means your body is producing ketones and you are getting some of your energy from those, instead of carbs that have been made into blood glucose. Oh, and before we move on, did you know that carbs are "the most important source of energy" for our bodies?
Anyway, according to Dr. Stefani Reinold, our bodies are never 100% in ketosis because they will always prefer glucose (carbs)! And they will break down muscle and other tissues to get that glucose (carbs). She says this is a good thing because if we got to a point where we couldn't burn glucose, we would be at risk for a life-threatening thing called ketoacidosis.
How was the keto diet invented?
It was developed in 1921 to treat epilepsy in kids. Acetone (a part of those little ketone bodies our body makes when we eat low carb high fat) turned out to have anticonvulsant properties. (Kind of cool! I'll admit!) However, when anticonvulsant medications were created in the 1970s, they stopped using the keto diet as a medical treatment. (Apparently it is sometimes used today, but only when someone has tried two different medications and neither of them has worked.)
In 2013, a Silicon Valley podcaster and author picked the keto diet up and from there it went viral. As these things tend to do on the internets.
Does the keto diet help you lose weight?
Yup! But mostly because you'll probably end up eating less calories overall. So you could probably lose weight without doing keto if you just ate less calories.
Now, whether or not that weight loss is sustainable is another question. Long term studies (meaning AT LEAST 2 years, preferably 5) show that weight regain happens.
This study showed "Percent BMI loss was no longer significant after [2 years], and weight regain became significant within [4 years] after surgery". This study looked at people in the BMI category of "obese" (a BMI critique is a blog post for another day) after 9 years (now THAT'S a long term study!) and found the probability of them attaining a "normal" BMI weight was 1 in 210 for men (that's .004%) and 1 in 124 for women (.008%). When looking at "morbid obesity" BMI, these numbers went to 1 in 1290 (.0007%) and 1 in 677 (.001%)! Last, the probability of people with "morbid obesity" achieving a 5% weight reduction after even 1 year was 1 in 8 for men (12%) and 1 in 7 (14%) for women.
So, when anything is promising us weight loss, we want to see studies with LONG TERM follow up and statistics show that it is sustainable.
And, I'll end this little tangent with a plug for focusing on behaviors instead of just weight. If it's really about health, then health promoting behaviors should be getting just as much attention as weight loss.
What are the benefits of the keto diet?
So, I did find a few potential benefits. I read research the best I can, but a lot of it was a little jargon-y. So, take all of this with a grain of salt.
First, it may help with certain congenital metabolic diseases that prevent the body from using carbs as fuel.
Second, there is some interesting stuff about how it may help with memory and cognitive disorders! This study had 23 older adults eat low carb for 6 weeks and saw their verbal memory improve, which is interesting for Alzheimer's. (This is a pretty low sample size, though.) Likewise, this study looked at 152 people (better sample size) with mild to moderate Alzheimer's and gave them an oral ketogenic compound every day for 90 days. They gave them an Alzheimer's assessment on day 45 and saw their scores differ from the placebo group. Oh, and this who study was double blind and randomized. However, you'll notice they gave them a compound. This wasn't them eating keto. So, that's something to consider.
Third, there is also interesting research on keto and Parkinson's disease. This study had 7 (once again, really small sample size) people eat according to keto for 28 days and found that 5 out of the 7 improved on a Parkinson's scale assessment. This could be due to the placebo effect, though since it wasn't blinded.
Last, there is conflicting evidence about using a ketogenic diet during chemotherapy.
Does the keto diet help lower your cholesterol?
I saw lots of claims that eating keto can lower your cholesterol. So, I looked for long term studies showing the effect eating keto has on your cholesterol and found this "long term" study that went for... 1 year lol. Long term? I don't think so! Clicked the next one and it was for 24 weeks.... nope! Clicked another and it was 12 weeks. If you find a study that shows it lowers cholesterol in humans over the long term (5+ years) please email me and I'd be happy to take a look and revise!
Does the keto diet protect your brain?
Even though some people claim it has "neuroprotective" facts, science says the effect it has on our brains is "yet to be established". So, jury is still out on this one!
Does the keto diet help with diabetes?
Does the keto diet help with polycystic ovarian syndrome (PCOS)?
There was one study on this but it only had 11 participants and went for 24 weeks. So, once again, small sample sizes and short term results make it hard to draw a conclusion!
What are the cons?
Sustainability: First things first, as with all diets, we have to ask ourselves: Is it sustainable? The keto diet is so strict, is it really something you can do for the rest of your life? And when you quit, you'll most likely gain back any weight you lost.
Increased heart disease risk: Diets that are high in fat are associated with higher risks of heart disease.
Higher lipid levels: Follow up studies have shown that people who eat low carb high fat have higher lipid levels. This study looked at the blood of 20 male runners (smaller than ideal sample size) and found that the men who had been eating low carb high fat for over a year had 65% higher plasma total cholesterol, 83% higher low-density lipoprotein, and 60% higher lipoprotein. They also found that their lipoproteins were distributed differently in their bodies. High volume exercise is supposed to lower these levels, so it's confusing. The authors thought this may have happened due to the low carb high fat (keto) dieters eating more saturated fat and cholesterol.
Fuzzy thinking: Not getting enough carbs can lead to fuzzy thinking. This study divided 19 women (smaller than ideal sample size) into a low-carb or low-calorie diet and then gave them cognitive assessments. They found that "during complete withdrawal of dietary carbohydrate, low-carbohydrate dieters performed worse on memory-based tasks than [reduced calorie] dieters. These impairments were [improved] after reintroduction of carbohydrates." This makes a lot of sense because our brain uses carbs as it's main source of energy and I think we all know how we get when we are hungry haha.
Linked to heart arrhythmia: Long term low carb diets have been linked to heart rhythm problems. This study looked at 14,000 people (that's a good sample size!) over the course of 20 years (and for a long time!) and found that “low carbohydrate diets were associated with increased risk of incident AFib [a type of heart arrhythmia] regardless of the type of protein or fat used to replace the carbohydrate". They had divided people into three groups of low (>44.8%), moderate (44.8%-52.4%), and high (52.4%) carbohydrate intake and found people who reported low carbohydrate intake were most likely to develop AFib [the type of heart arrhythmia]. In fact, they were 18% more likely than the "moderate" carb eating group and 16% more likely than the "high" carb eating group.
Low micronutrients: Considering this diet says you can't eat fruits or vegetables (if they put you over your carb limit), it's possible eating keto and make you low on micronutrients. This study looked at Atkin's (which also limits carbs) and found that "an individual following a popular diet plan... has a high likelihood of becoming micronutrient deficient; a state shown to be scientifically linked to an increased risk for many dangerous and debilitating health conditions and diseases".
Deydration: Too many ketones can lead to dehydration.
Constipation. The keto diet is low in fibrous foods like grains and legumes.
Higher morbidity rates: Now, I've saved the best for last. If you can believe it, eating low carb high fat is associated with HIGHER rates of morbidity.
Researchers look at data from the National Health and Nutrition Examination Survey 1999-2000. They looked at 24,825 people who were followed for an average for 6 1/2 years. The average age was 47 and it was pretty evenly split men and women. They divided them into four categories based on their carb intake. Group 1 averaged 66% carbs, group 2 averaged 57% carbs, group 3 averaged 49% carbs, and group 4 averaged 39% carbs. (The Dietary Guidelines for Americans recommends 45%-65% of your total calories be carbs.) They compared the lower carb groups (2, 3, and 4) with the higher carb group (1). Oh, and they controlled for age, sex, education, marital status, poverty-to-income ration, total energy intake, physical activity, smoking, alcohol consumption, BMI, and a bunch of other stuff.
They found that the people in the lowest carb intake group (group 4) had a "32% increase in total mortality, 35% increase in cancer mortality, a 51% increase in coronary artery disease, and a 50% increase in stroke mortality".
Other resources on keto:
All the studies are linked above!
Listen to Dr. Stefani Reinold's podcast on keto (and other diets) here.
Listen to Science VS check the research on keto here.
Read a dietitian's blog post about keto here.
So, is keto fact or fiction??
I'll let you decide! Comment below what you think. As always, feel free to email me if you find links to interesting research!
Oh, and if you're in Seattle and would like to schedule an appointment for therapy, I am taking new clients! Click here for more information.
P.S. There were 25 citations in this blog post because #citationsaremylovelangauge. If you found this post helpful, please share it! I don't get paid to post anything on this blog and it all takes quite a bit of time!