The keto diet has risen to popularity based on numerous experienced health benefits such as weight loss. As a result, it has garnered interest from people who would like try an alternative to traditional diets.
However, a common questions we get asked is what are the drawbacks of keto?
In this article we’ll explore both sides of the coin; the advantages and the disadvantages. It is our hope that by having this holistic understanding, you will be able to make more informed decisions about your diet and health.
Table of contents
Pros of the keto diet
Weight loss
Weight loss, especially during the short-term, is one of the main reasons for the popularity of the keto diet.
There is a mountain of anecdotal evidence that keto leads to significant weight loss, with forums filled with people talking about 10, 20 or even 30 pounds of weight loss in a short period of time.
The total amount of weight loss, in combination with the short time period to experience the results, is key to keto’s success.
The scientific literature has some conflicting reports regarding diet macronutrient composition and weight loss.
However, there is a significant amount of evidence that supports the association between low carbohydrate diets and weight loss[1].
For example, a meta-analysis of 8 studies demonstrated that ketogenic diets led to substantial weight loss as well as significant reductions in waist circumference[1].
Reduction in appetite
Keto diets have been strongly associated with reductions in appetite, due to the higher satiating effects of proteins and fats compared to carbohydrates[2].
This is extremely significant when it comes to weight loss and diets, and is one of the reasons the keto diet leads to weight loss.
Studies have demonstrated that cravings and feelings of hunger are associated with less weight loss and lower diet compliance[3].
Basically, if you feel more hungry during your diet, you are more likely to give in to your temptations.
Following a diet like keto, which leads to higher levels of satiety, is therefore a good way to increase diet compliance and progressive weight loss.
Improved glycemic control and insulin sensitivity
Obesity is well known to be a factor in the development of insulin resistance.
There is also evidence that insulin resistance may contribute to obesity and therefore has a bidirectional relationship[4].
The keto diet has been shown to improve insulin sensitivity and impart greater glycemic control compared to higher carbohydrate diets[5].
Factors such as fasting blood glucose and insulin levels show improvement after adhering to a keto diet[5][6].
This is particularly beneficial to individuals with type II diabetes, or overweight individuals with insulin resistance.
As insulin resistance and obesity are associated with a host of other metabolic conditions, as well as diseases like cancer, improving insulin sensitivity can have a host of secondary benefits[4].
Treatment for epilepsy
One of the key benefits of the keto diet is it’s ability to treat epilepsy.
Epilepsy is a health condition that results in seizures. Many people take anti-seizure medication, but for some individuals, these medications are not effective in controlling their seizures[7].
It has been known since the 1920s that a ketogenic diet can help improve seizure frequency and severity[8]. As a result, the ketogenic diet is currently an established treatment for children with epilepsy, but adults can also benefit[7][8].
Normally, anti-seizure medications would be used. But after 2 treatments have been proven to be ineffective, the keto diet intervention is the prescribed treatment[7].
This has delivered impressive results and helped numerous epileptics with their condition[8].
Increased energy
A benefit that is frequently mentioned on the keto diet is increased energy.
Anecdotal evidence from online forums suggests that people on the keto diet feel more energetic and have increased mental focus.
This could be due to the greater stability in blood glucose and insulin levels on the keto diet. With more consistent blood glucose levels, people may be able to focus for longer periods of times and generally feel more energetic.
This is supported by a meta-analysis on the impacts of carbohydrate consumption on mood[9].
The study found that carbohydrate consumption was associated with increased fatigue and less alertness compared to placebo[9].
By eliminating carbohydrates, keto can result in improvements in alertness and energy, which can have an overall beneficial impact on your life.
Improved skin
The association between diet and skin is a complex one.
However, there is some evidence that ketogenic diets are associated with improvements in certain skin conditions.
After being on a keto diet, many people notice their skin looks clearer and has improved tone. Some of the improvement in skin tone is likely due to reduced water retention, but improvements in other skin ailments are also apparent[10].
Emerging evidence investigating the link between diet and skin health has found that low calorie ketogenic diets can show improvements in skin conditions such as acne and psoriasis[11][12].
A study conducted in patients with acne found improvements in lesion count in the low glycemic (keto) group, compared to the high glycemic group[13].
However, patients on the low glycemic diet also experienced weight loss, so it is unclear whether the keto intervention or the weight loss was chiefly responsible for the improvements in acne[13].
Keto may improve skin health due to the lower consumption of carbohydrates, which reduces overall body inflammation. The link is promising but requires further research.
Numerous additional health benefits
Low carbohydrate diets have been linked to a number of significant health benefits.
Following a keto diet has been associated with reductions in hypertension, inflammation and improvements in cardiovascular risk factors and cognition[14].
Studies have demonstrated improvements in both systolic and diastolic blood pressure following a ketogenic diet intervention[15].
In addition, cardiovascular risk factors such as triglyceride levels were shown to improve with the keto diet[14].
There is also emerging evidence that ketogenic diets are beneficial for more serious diseases such as cancer as well as neurodegenerative diseases, such as Alzheimer’s[16][17].
Cons of the keto diet
Keto flu - initial side effects
As many of you may already know, starting the keto diet can be associated with a number of initial, unpleasant side effects.
(Read more in our article “Top 10 short-term side effects of the ketogenic diet”)
This is colloquially referred to as the “keto flu,” and generally lasts from a few days to weeks when starting the keto diet[18].
Symptoms of the keto flu include headaches, fatigue, gastrointestinal issues (e.g. diarrhea or constipation), nausea and others. These symptoms can be quite unpleasant and can cause people to abandon the keto diet[18].
While they are unpleasant, it is important to remember that they are usually self-limiting, and should resolve within a few weeks.
Potential nutritional deficiencies
As the keto diet severely restricts the entire food group of carbohydrates, there is a possibility of nutritional deficiencies.
Many carbohydrates contain important nutrients such as fibre and micronutrients. When eliminated, this can lead to nutritional deficiencies, especially if keto-friendly alternatives are not found.
Studies examining micronutrient intake on low carbohydrate diets have found notable decreases in certain micronutrients, notably; thiamine, folate, magnesium, calcium, iron, and iodine[19].
If not addressed, these nutrient deficiencies can lead to health conditions and deteriorating overall health.
Fortunately, most of these can be relatively easily resolved through a diverse keto diet, combined with a healthy dose of micronutrient supplementation.
Check out our guide on common nutrient deficiencies on the keto diet.
Cardiovascular risk factors - LDL
It may be confusing to list cardiovascular disease risk as a potential con of the keto diet when it has also been listed as a potential pro.
Let us explain.
Low carbohydrate diets have indeed been shown to improve many factors associated with cardiovascular diseases.
However, some studies have also shown an increase in low density lipoprotein (LDL) cholesterol. LDL-cholesterol is the ‘bad’ cholesterol, large quantities of which can lead to atherosclerosis and cardiovascular disease[20].
Several studies have shown that the keto diet leads to increases in LDL-cholesterol, which is the reason for the concern[21][22].
However, upon closer inspection, it appears these studies followed keto diets that were higher in saturated fats[21][22].
Keto diets with a high proportion of unsaturated fats did not result in the same level of increase in LDL-cholesterol[20].
So high LDL-cholesterol levels are strongly associated with cardiovascular disease. In addition, the keto diet can raise LDL-cholesterol, which could potentially impact cardiovascular health.
Decreased muscle mass and reduced hypertrophy
A potential con of the keto diet is the impact it has on muscle strength and hypertrophy.
A small study followed participants over a 3 month period and fed them either a keto diet or a more traditional Western diet. The study found that although the keto group lost an appreciable amount of body fat, they also lost leg muscle[23].
As a saving grace however, strength did not decline within the keto group, and was comparable to the Western diet group[23].
Another study was conducted on bodybuilders, to compare the impact of the keto diet vs Western diet on body fat and muscle mass over a 2 month period[24].
Although there were similar increases in strength, the keto group did not increase lean muscle mass. This was in contrast to the Western diet group, that showed significant increases in muscle mass[24].
This highlights the concern that the keto diet could lead to decreased muscle mass, and impair muscle hypertrophy.
Kidney stones
Development of kidney stones is a real risk in people following a strict ketogenic diet, especially over the longer term.
Studies have found that the incidence of kidney stone development in people following the keto diet is approximately 5-6%[25].
It is thought that the high amounts of animal protein in the keto diet are responsible for the development of kidney stones. In fact, high consumption of animal protein is a well-established risk factor for kidney stones[26].
When you combine the increase in animal protein with the decrease in certain fruits and vegetables, you end up in a situation that promotes the development of kidney stones.
Studies have however shown that supplementing with potassium citrate can help prevent kidney stones[27].
In a study of children on the keto diet, only 2% developed kidney stones when supplemented with potassium citrate, compared to 10.5% in the control group[27].
Restrictive food choices
While not directly related to physical health, another con is that the keto diet is quite restrictive.
By eliminating carbohydrates, you will no longer be able to eat many of your favourite foods, such as pizza, pasta and burgers.
In addition, the keto diet can be more challenging from a food preparation perspective, and require more planning in advance. Keto foods are generally fresh and require more cooking than ready-made meals, or oven foods.
For some, this may not be a challenge on a day to day basis, but can make eating out a real challenge. Most restaurants and cafes are not designed with a keto diet in mind, so finding keto options is difficult and expensive.
Constantly being vigilant about your diet can be draining and may mean you don’t enjoy food the same way you used to.
Long-term sustainability
One of the main cons that people mention about the keto diet is that it isn’t sustainable in the long run.
Many people view keto as a way to quickly drop pounds and then return to their old eating patterns. As mentioned, when you completely eliminate your favourite foods, it can be very challenging to maintain that diet for a long period of time.
The planning and preparation takes a significant amount of time, which can be unrealistic if you have a particularly busy job or other commitments.
Final thoughts
Overall, the keto diet can be used as a lifestyle to help you reach your weight loss goals and improve your overall health.
Like any diet, there are drawbacks, many of which can be addressed or mitigated. However, some of the negatives are a reality of the eating style. Hopefully this article has provided you with a bit of perspective about the pros and the cons of the keto diet, and helps you make an informed decision about whether it is the right diet for you.
