I review the pros and cons of the Keto Diet and what I actually think about people using the ketogenic diet for weight loss.
I wasn’t planning on writing about the ketogenic diet but that all changed with my recent YouTube video. If you guys caught this video on my channel, my girl Abby Langer and I found a hilarious Reddit thread that shared some keto-followers favourite “strange but delicious” keto-friendly meals and snacks. Let’s just say, it was extreme. I was by no means under the impression that everyone (or even a large number of people) on the Keto diet ate that shit. But, I get why some viewers on youtube maybe thought that and they got PISSED. Like, viciously pissed.
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So, jokes aside, I decided to share what I ACTUALLY think on all things keto and give you guys a comprehensive review of the diet so there’s no confusion. At the end of the day, ‘haters gon hate’ but at least I can sleep at night knowing I’ve done my due diligence in whole heartedly giving you all the necessary information around this diet.
Let’s dive in.
What Is the Keto Diet?
If you haven’t already jumped on the keto diet bandwagon, I’ll give you a brief introduction. Basically, the ketogenic diet is a super high in fat (80% of your diet is fat), a super low carbohydrate (<5% of your diet) and moderate in protein (15-20% of your diet). Surely, not the most balanced of diets considering Health Canada your diet should contain 20-35% of protein, 45-65% of carbohydrate and 10-35% of fat. So how to you meet that skewed macronutrient distribution? Well, you load up on keto diet staples like meat, fish, butter eggs, cheese, heavy cream, oils, nuts, avocados, seeds and low carb green vegetables. And you cut out all your go-to carb sources like grains, rice, beans, potatoes, sweets, milk, cereals, and fruits. These kinds of restrictive diets tend to make nutrition professionals like dietitians run for the hills but I’m going to give it my honest unbiased account.
What is Ketosis?
Ketosis is natural and normal, though arguably not optimal.
Our bodies run well on glucose (carbs)–they give us the necessary energy we need to function on a daily basis. When our body doesn’t get enough glucose (either because we’re cutting carbs too low, OR we haven’t eaten in too long), our body kind of freaks out and looks for other forms of energy to satisfy that role. That’s where the fat comes in. Without carbs, our insulin levels drop and fat is released from our cells. The fat overwhelms the liver which turns it into ketones, our body’s second choice to carbs for energy.
So, to confirm. Yes, your brain CAN function without carbs, but carbs are still your brains favourite good and some brain cells can only use glucose for fuel.
Ketoacidosis in Diabetes
It’s important we distinguish between the process of ketoacidosis seen in type 1 diabetes and this ketosis that so many people on the keto diet are striving for. If someone with diabetes lacks enough insulin and/or does not eat enough carbohydrates, they risk entering a state known as ketoacidosis. For those with uncontrolled diabetes, this can increase the levels of ketones in the blood, increasing the acidity of the blood, and potentially leading to a coma or even death. In ketosis for a healthy individual, the level of ketones in the blood never reaches these crazy high levels so it’s generally safe for the average healthy individual.
Bottom line: Ketosis is not ketoacidosis and is generally safe for most healthy people.
Keto Diet History
So where did the ketogenic diet come from? Interestingly enough, this fad diet didn’t spark from a celebrity endorsement or some guy missing a medical license. There’s evidence of the keto diet being used back in the early 1920s to treat severe childhood epilepsy and it’s still being used today for that purpose. Research suggests that the production of ketones may influence neurotransmitter activity in neurons allowing for a reduction in seizure attacks. A recent Cochrane Review demonstrated a 30-40% reduction in seizures compared with non-keto diet controls. One thing to keep in mind, however (which is a theme when discussing the keto diet) is that it’s generally difficult to adhere to and difficult to tolerate for a lot of people. In other words, people go on it and then come off it pretty damn quick.
Once the medical community acknowledged the keto diet’s effectiveness in reducing seizure episodes, they decided to look further and study its impact on neurological diseases in general. Neurological diseases share a common problem – a deficiency in energy production. Ketones provide that energy for normal brain cell metabolism, and may even be a more efficient when the body is in starvation mode. When patients were put on the keto diet, the number of mitochondria (energy powerhouse) in brain cells increased. Ketones may also act as an antioxidant by inhibiting the formation of reactive oxidant species, which is why they may have promising effects in the treatment of certain cancers in conjunction with chemotherapy. Really exciting stuff, actually. Let’s look at a few other specific neurological diseases and the impact of the keto diet there.
In a study, Alzheimer’s patients fed with a ketogenic diet experienced improvements in their symptoms, which again may be due to the improved mitochondrial function. In another study, patients with Alzheimer’s were given a drug with ketones and after 90 days, they experienced improvements in cognitive function.
In a pilot study, five out of seven patients trialed a keto diet for 28 days and showed marked reduction in physical symptoms. Obviously, we need more research here but its an exciting finding.
This also may be too premature, but an animal study found that the keto diet delayed motor neuron death and showed MS improvements, however it did not increase the life span of the subjects.
Ketosis and Cardiovascular Health
What about heart health and the keto diet? Previous older schools of nutrition would purport that a diet rich in fats (specifically saturated fats) would be detrimental for heart health, but more recent research suggests that saturated fat is not as bad as previously believed. There is actually a tiny little bit of evidence that a keto diet may improve triglyceride, HDL and LDL levels. Like here and here. We’ll definitely have to wait to see how that research unfolds because there is definitely a lot of competing elements at play.
Keto Diet and Type 2 Diabetes
There have been many attempts at studying the link between type 2 diabetes and the keto diet. In one study, a strict low-carbohydrate diet was administered in obese patients with type 2 diabetes. After 14 days of being on the diet, the glucose levels of participants normalized, their hemoglobin A1C decreased from 7.3% to 6.8% and insulin sensitivity improved by 75%. Some of this study’s limitations include the short duration, the small sample size and the weak control group. In another study, 84 obese patients with type 2 diabetes were randomized to either a low-carbohydrate keto diet or a low-glycemic reduced calorie diet. At the end of the study, both groups experienced improvements in glycemic control however the low carb keto group had greater improvements in hemoglobin A1c and higher HDL levels compared to the low-glycemic group. These results suggest that low carbohydrate interventions may be effective at improving glucose control.
Keto Diet and Cancer
There is exciting research on the role of a keto diet as a form of treatment for cancer. In one study, the use of a keto diet on patients with advanced cancer was deemed safe, and some evidence suggested it played a role in stabilizing the disease or resulting partial remission. In another study, the keto diet was used as a form of therapy for patients with malignant brain cancer. The study found that the keto diet may carry anti-tumor effects when administered in experimental animal and human brain tumors. The researchers believe this may be due to the reduction in calories, which reduces the circulating glucose needed for tumor growth. It is still unsure whether a keto diet per se plays a role in this or simply calorie restriction. All of this is to say that the research is preliminary, however still promising.
Keto Diet and Sports Performance
Traditionally, in the sports nutrition field, we talk about the importance of timing carbohydrate and fluid intake on improving sports performance. For some time now, research has been looking at the role of very low carbohydrate diets on sports performance. Trailblazers in keto and sports performance research like Dr. Stephen Phinney have been conducting studies in this area since the 80s. In one of his studies, the glycogen stores of cyclists on a keto diet were not completely depleted and lipid oxidation was increased. Researchers concluded that the body was able to adapt to the lack of carbohydrates and preserve what was needed to use the fat as fuel. However, based on the VO2 max breath test, since the body was attempting to preserve the carbohydrate during the exercise, it appears that the intensity of the exercise was limited. In a more recent study, off-road cyclists following a keto diet experienced small improvements, but still not significant enough to make strong conclusions.
The only difficulty with some of these studies is that they tend to have small sample sizes, like this one that only has five cyclist participants and the data was largely skewed by the fact that only ONE cyclist experienced a large enhancement of exercise capacity after the keto diet. Their studies also tend to be short term. Back in 2014, Phinney and scientist Tim Noakes wrote an editorial that stated that in the past 31 years, there have only been a handful of studies measuring sports performance and low carb diets. Out of a total of 11, only 3 found exercise improvements. So far, no studies have evaluated the long term effects of the keto diet on sports performance (more than 6-12 months). That does not mean that the keto diet won’t be effective, but for now we don’t yet have the evidence to draw strong enough conclusions to call it standard best practice.
Keto Diet and Weight Loss
Aside from the therapeutic uses of a keto diet, most people are using this diet for rapid weight loss (surprise, surprise). Let’s take a look at what the literature says.
First of all, I can’t deny the fact that people will lose weight on a keto diet. Here’s why. First of all, you’re eliminating a major food group. When you do that, you limit your food options and most likely your food intake, so it’s not rocket science that you’ll likely lose weight. Second, most people on a low carb diet tend to increase their protein intake in the absence of carbs and there is some evidence that consuming higher amounts of protein may have some weight loss benefits. All of these effects take time, but a reasonable explanation as to why the keto diet leads to rapid weight loss is due to the loss of water weight. One of the concerns with the keto diet is the loss of muscle mass and the depletion of glycogen stores. Glycogen, which stores our glucose, also stores water, so when stores are depleted, we flush out excess water. In other words, that rapid weight loss isn’t fat, it’s just water.
The keto diet also has an impact on our hormonal levels. Many studies have looked at whether the state of ketosis suppresses our appetite through the actions of leptin and ghrelin. A 2013 study found that after patients lost weight on a keto diet, our hunger hormone (ghrelin) was altered and suppressed. A systematic review also concluded that the state of ketosis appears to be a plausible explanation for the suppression of appetite. So this the keto diet may be good for dieters who can’t stand the discomfort of hunger. Finally, the keto diet also may have an impact on our stress hormone, cortisol. This was demonstrated in a Harvard study where the keto diet resulted in an increase in cortisol in individuals following a very low carb keto diet. High levels of cortisol is associated with insulin resistance, cardiovascular disease and may promote fat accumulation.
So we got the short term effects, but what about long term impacts of the Keto Diet?
So one study looked at the long-term effects of a keto diet in obese patients and after 24 weeks, patients lost weight, reduced their total cholesterol, LDL, triglycerides and increased their HDL. Another study conducted on 132 obese patients found that the low carb (keto) group lost more weight than the low fat group while improving biomarkers like decreased triglycerides, improved insulin sensitivity, and decreased fasting glucose. This all was confirmed in a 2013 meta-analysis, 13 RCTs (1,569 participants) found that patients assigned to a very low carbohydrate diet resulted in greater weight loss compared to those assigned to a low-fat diet.
Having said that, there are also studies suggesting that long term carbohydrate restriction diets (aka. the keto diet) may result in fast short term weight loss but people gain it all back in the long term. An RCT put 63 individuals on a low-fat diet or a low carb diet, and the study found the low carb dieters lost more weight compared to the low fat group by month 3 and 6, but that the weight loss evened out by month 12. This was confirmed by a Meta-analysis which found that while low-carbers lost more weight than low-fat dieters but the differences disappeared by the one year mark.
Another thing we know about diets and weight loss is that the results are not easily maintained. I’ve written about this in depth with regards to the participants on the Biggest Loser. This was evident in a study analyzing 31 long term studies on dieting, which found 2/3 of dieters put back the weight they lost. Other research has reported the failure rate may be as high as 95%. This isn’t specific to the keto diet but rather, any diet that is restrictive and unrealistic may be nearly impossible to sustain.
So while the keto diet, like any diet, may result in weight loss, is it sustainable and what are the dangers of doing this long term?
Potential Dangers of the Keto Diet
Loss of Muscle Mass
A huge concern with the keto diet is the maintenance and potential loss of muscle mass. Many people will just think: hey, dummy, then just eat more protein. However, some research has shown that even if your protein intake remains constant, a low carb diet may promote muscle loss. A study from the Netherlands confirmed these findings. In the study, participants were given three diets (high carb, moderate carb, low carb) and moderate protein. The study found that those following a low carb diet experienced increased muscle breakdown. This is because when we eat carbohydrates, we produce insulin which promotes muscle growth. This is why athletes depend on carbohydrates (along with protein) to fuel their performance. When we eat carbs, the insulin release “unlocks” our muscles to let the protein in so it can do its job at building our muscles. So, when we skip the carbs all together, muscle glycogen stores get depleted, we lose out on those muscle building opportunities. Forget about high intensity training. A depleted glycogen store also means our workouts will suffer because we just don’t have enough oil left in the tank.
Keto “Flu” and Bad Breath
Since our body isn’t used to using ketones, we tend to feel flu-like when in ketosis. Lots of brain fog, fatigue, headaches, nausea and poor endurance. You also get bad smelling breath, sweat and pee from the acetone (a byproduct of fat metabolism). Sexy? Not so much. Thankfully, if you are in ketosis long enough, a lot of people report that most of these side effects start to go away.
Constipation is one of the most common onset side effects of following a keto diet. A ten-year study looking at the effects of a keto diet on 48 children found that 65% of the children experienced constipation. This is all due to the fact that a low carb diet means you’re missing out on fibre-rich grains, fruits and certain vegetables.
Feeding Tube Diet (WTF?!)
Before I continue, I must admit that this next diet practice is not practiced by all keto dieters, however, I had to mention it because it’s pretty disturbing. One of the founders of the keto diet as a weight loss strategy conducted a study where 19,000 patients were fed for ten days via a feeding tube. The feeding tube solution contained 800 calories, moderate amounts of protein and no carbohydrates (again, the standard keto diet). I’m sure you can imagine the results. Patients lost 10% of their weight, and 57% of that was fat mass. My bet is, once they unhooked from the feeding tube, they gained all that weight back just as quickly as they lost it.
Since the study, there have been a number of clinics popping up country wide providing this service to the public. This scares the SHIT out of me.
Feeding tubes are not a quick fix to help you get into your wedding dress. They’re a last resort, are solely temporary and are only used if an individual cannot eat or they have GI issues.
Aside from the crazy cost of doing something like this (close to $1,500), there are a shit ton of potential complications. Patients may experience infections, aspiration, erosion of the tissue in their nose and throat, along with electrolyte imbalance. The rush of minimal nutrients from a feeding tube can disrupt your body’s homeostasis and cause serious consequences. Sure you’ll lose weight, but at what cost? Um, no thank you.
With the high intake of fat, are we concerned about the high intake of cholesterol? YEP. A study using the keto diet as a form of treatment for epileptic seizures in children found that after 6 months of administering the diet, triglyceride levels increased, total cholesterol levels increased, and HDL and LDL increased. These results suggest that over time, a keto diet may lead to an increased risk of hypercholesterolemia and hypertriglyceridemia. In the same ten-year study, 40% of patients developed hypertriglyceridemia and 29% of patients experienced hypercholesterolemia. So, if heart disease runs in your family, you may want to bow out now.
Strict dietary restriction means we may be missing out on crucial vitamins and minerals. With the keto diet, major minerals that are missed include sodium, potassium and chloride which is why they are typically supplemented with a table salt tablet. Other vitamins that might be missed out on include vitamin D, calcium, magnesium, selenium and zinc. The lack of vitamin D and calcium puts keto dieters at risk for reduced bone health and increased risk for fractures and long term bone diseases.
The Verdict on the Keto Diet
Cutting out a whole food group (or in this case, more than one) is a dietitian’s worse nightmare. It not only makes it a really hard diet to follow, but also stresses the hell out of your body and makes it work a lot harder to keep up.
Carbohydrates make up the life blood of our body’s ability to function. Our body’s need it to run efficiently, promotes muscle growth and endurance in athletes and gives us the energy to get through the day.
We’ve seen the role of a keto diet in neurological diseases and as a form of treatment. The keto diet may also act as a quick fix rapid weight loss tool just like any other restrictive diet. While the risks are likely low if you’re an otherwise healthy individual, I still wouldn’t brush them off as NBD.
More problematic for me is the fact that ANY diet, especially one that is as devastatingly restrictive as the keto diet, is likely to encourages disordered eating behaviours. I’ve written about my own experience with , and this is a pretty scary reminder of how UNHEALTHY that world can be.
I’m a big believer that everything – especially carbs – can be enjoyed in moderation and the best diet is just whatever eating pattern you find most pleasurable that also meets your body’s unique needs. I don’t know about you, but I need a summer peach, or a pillowy slice of focaccia, or a mindful bowl of pasta.
What does your body need?
Leave me a comment below. Have you tried the keto diet for weight loss?
Have you been successful?
Would you ever attempt a NO CARB diet?