A special diet called ketogenic diet, or keto diet, has been trendy for quite a while. I’ve seen online articles about ketogenic diet, people talking about and trying keto diet, even friends around me were doing it. But what exactly is ketogenic diet, how does it work, and does it really work wonders as many people promote? I’ve done some research and here’s what I found.
What Is Ketogenic Diet?
Ketogenic diet is a diet that contains very low carbohydrates, adequate protein, and high fat. The history of ketogenic diet can be traced back to a century ago, when doctors used it as a cure for epilepsy, mainly in children. It has also been studied for use in other diseases like Alzheimer’s, autism, Parkinson’s, sleep disorders etc. Patients with type 2 diabetes have shown evidence of improvement after taking a ketogenic diet.
It’s probably because of its weight losing side effect, that ketogenic diet has also become what some will call “fad diet”, for those wanting to shed stubborn pounds but have failed using other weight loss methods during the years.
How Does Ketogenic Diet Work?
Normally our recommended daily calorie consumption is around 55% to 60% carbohydrates, 10% to 15% protein, and 35% fat. This is because carbohydrates are the main energy source in our body. Once one starts ketogenic diet, with very low amount of carbohydrates, the glycogen in the liver will be depleted within 24 hours, and free fatty acid will then be used to generate energy. When free fatty acid is oxidized by the liver, three organic compounds - β-hydroxybutyrate, acetoacetate, and acetone, or collectively known as ketone bodies, will be formed, enter the blood and be transported to other parts of the body to provide energy, including the brain, but only partially. The state that ketone bodies accumulate in the blood is called ketosis.
Same with other weight loss diets, ketogenic diet limits daily calorie consumption to create a calorie deficit. Based on the fact that even a lean person (65kg, 12% body fat) stores only 2,500 kcal energy from body glycogen, but over 74,000 kcal energy from body fat, mainly subcutaneous and visceral fat, theoretically having a very low-carb diet makes the body enter ketosis in a very short time, and keeping a calorie deficit forces the body to consume body stored fat for energy, similar to fasting. In fact, ketogenic diet is considered partial fasting.
The biggest advantage of Keto may be that fat is very satiating, which helps to curb food cravings, especially when one is on a diet.
This is claimed to be very helpful for those who have type 2 diabetes characterized by insulin resistance, and their body fails to properly respond to insulin, which “regulates the metabolism of carbohydrates, fats and protein by promoting absorption of glucose from the blood into liver, fat and skeletal muscle cells” and therefore controls blood sugar level. Ketogenic diet may be beneficial to them because carb intake is limited to minimum. A study has also shown that ketogenic diet “had beneficial effect on…insulin resistance”.
Therefore, it is understandable why keto diet has gained so much traction among people who are obese or diabetic. But as an unconventional diet, what adverse effects may one have to face?
Side Effects of Ketogenic Diet
Similar with other weight loss diets, since brain tissue relies heavily on carbohydrates as a source of energy, it will not be a surprise that lack of carbs in the diet will have negative cognitive effects, for example, difficulty in concentrating. A lack of carbohydrate supply also impairs ATP-PCr and glycolytic system, which is the energy source for anaerobic exercise like strength and resistance training. This is proved by a study, which shows that “short-term low-carbohydrate, ketogenic diet reduces exercise performance in activities that are heavily dependent on anaerobic energy systems”.
Apart from those mentioned above, ketogenic diet has common side effects including:
- digestive issues like constipation or diarrhea in the beginning,
- change of smell in breath and urine due to ketone bodies accumulation,
- further water loss because of very low carbohydrate intake,
- and dysmenorrhea in women.
Other side effects and deficiencies include:
- increase in cholesterol level, although it’s said that it can be solved by substituting saturated fat with polyunsaturated fat,
- vitamin deficiency due to the nature of the diet – non-holistic, little access to carbs and fruits, although it’s said that taking vitamin supplements can solve the problem,
- possible loss of fat-free mass (muscle mass) if protein intake is not enough.
Is Ketogenic Diet Worth Trying?
For people with underlying conditions like obesity, type 2 diabetes, or neurological disorders like epilepsy mentioned at the beginning, ketogenic diet may be worth trying after consulting with their own doctors. But what about healthy people who don’t have underlying conditions? Is ketogenic diet worth trying for them?
If you still have this question unsolved in mind after reading the side effects and possible safety issues mentioned above, please also consider the economical aspect.
First of all is the increase spending on substituting carbohydrate with fat. To avoid potential increase in cholesterol level, polyunsaturated fat is needed, especially omega-3 rich food like salmon. This further increases the cost.
Second, in order to maintain muscle mass, more protein will be needed. Ketogenic dieters are suggested to consume 0.8g protein per pound lean body mass, or 1.7g per kg lean body mass to prevent muscle loss, as opposed to Recommended Dietary Allowances (RNA) of 0.8g per kg BODY WEIGHT. This means more money will be needed to be spent on meat, fish or protein supplements.
Third, the nature of ketogenic diet requires vitamin supplements, which is another expense.
Some say that if you are on a budget, you can figure out strategies to get cheap but good protein sources. Then it becomes a matter of spending more time versus more money.
Is It a Good Lifestyle?
Again, for people who have underlying conditions that may benefit by improving their current condition, ketogenic diet can be a good lifestyle. For healthy individuals this is most of the time not the case.
Apart from spending more money on food, change of lifestyle from traditional balanced diet to ketogenic diet also has other concerns.
It’s not sustainable and less eco-friendly. Ketogenic diet requires more consumption on fat and protein, which is mainly from animals, unless the consumer is vegetarian. Besides, many dieters give up and go back to their former lifestyle. Their weight bounces back afterward most of the time, just like other “fad diets”.
Change of lifestyle is not easy, and consistency is the key. Unbalanced diets have the problem of cravings for the nutrients that one lacks or even health problems after a certain amount of time, which makes it hard to persist. So instead of either spending more money or time, and even risking someone’s own health, why not take a traditional balanced diet with exercise that’s easier to stick to?
 Rahel Kristina Stocker, Emilie Reber Aubry, Lilly Bally, Jean-Marc Nuoffer, Zeno Stanga. Ketogenic Diet and Its Evidence-Based Therapeutic Implementation in Endocrine Diseases. 2019 Jun;108(8):541-553. doi: 10.1024/1661-8157/a003246. PMID 31185843.
 Kymberly A Wroble, Morgan N Trott, George G Schweitzer, Rabia S Rahman, Patrick V Kelly, Edward P Weiss. Low-carbohydrate, Ketogenic Diet Impairs Anaerobic Exercise Performance in Exercise-Trained Women and Men: A Randomized-Sequence Crossover Trial. 2019 Apr;59(4):600-607. doi: 10.23736/S0022-4707.18.08318-4. PMID: 29619799.
 Ketogenic diet: Is the ultimate low-carb diet good for you? Harvard Health Publishing. 2017 Jul.
 Keto: The Home for Ketogenic Diets. Reddit.
 Physiology of Sports and Exercise. Six Edition. W. Larry Kenney, Jack H. Wilmore, David L. Costill.