The Ketogenic Diet
The Ketogenic Diet | Let's Talk About it
With the many diets that exist today, the ketogenic diet is arguably the most popular. Often being lumped together with the Paleo, South Beach, and Atkins diet to name a few, a true ketogenic diet actually differs when compared to these diets in certain respects [7]. Unlike these diets that appear somewhat similar, a true ketogenic diet puts a higher emphasis on fat (requiring an intake of up to 90% of your daily calories [7]) while putting limitations on the amount of protein and carbohydrate that you can eat as a result. When done correctly, the body is then forced to convert fatty acids into what are known as ketone bodies to provide us energy in the place of glucose. This results in the state known as nutritional ketosis [9]; giving the diet its notorious name.
The 3 ketone bodies we create.
However, with all the buzz lately surrounding this style of eating, it often gets people thinking as to what this diet actually entails. From better mental focus to less systemic inflammation; the anecdotes around a ketogenic diet can often be bold without much context as to why that is.
But hopefully today, we can better understand the nuts and bolts behind this diet and what it actually means for the people wanting to try it. Because although the diet seems simplistic on the surface, there are a few more nuances behind how to follow this diet correctly. So without further ado, let's dig into the ketogenic diet, how it works, and how you can use it to your advantage without all the confusion behind certain misinformed advertisements. Bulletproof coffee anyone? Yeah, me either.
Ketosis | The Definition And The Guidelines You Should Follow
Keto, or ketosis by definition, is a normal metabolic process that occurs when your body lacks a molecule known as glucose for fuel. Glucose, which is classified as a simple sugar, is the body's preferred source of fuel and is typically metabolized first for energy whenever a meal is eaten [8].
Glucose molecule
If your body becomes deprived of glucose via low carb consumption or glycogen depletion (carbohydrates that are stored within the liver and muscle), your body then has the ability to convert a molecule known as Acetyl-CoA (which is synthesized from fatty acids and other molecules) into 3 distinct ketone bodies for fuel in the place of glucose. Also termed ketosis.
Once inside the muscle, the ketone body generates ATP
Put simply, once carbohydrates are restricted to a certain extent, your body will eventually synthesize ketone bodies to take their place. This factors in the consumption of protein as well, since, when protein is consumed over sufficient amounts, protein can be converted directly into glucose for the body to use. This process is called gluconeogenesis [1][10].
Misconceptions Of A Ketogenic Diet
Common misconceptions around a ketogenic diet are the idea that vegetables, various sources of fats, as well as protein can be consumed with no limitation whatsoever. However, this is a common mistake. Certain fat sources, like avocado and peanut butter, contain relatively high amounts of carbohydrates and therefore shouldn’t be consumed in excess without being accurately accounted for. On the other hand, consuming too much protein can synthesize glucose naturally once your protein requirements are in fact met.
Therefore, a ketogenic diet shouldn't be confused with a ‘high protein diet’ and it should also take into consideration the carbohydrate content from the various sources of fat that you consume. Vegetables also should not be consumed loosely as vegetables alone are primarily carbohydrates. In short, all 3 macronutrients have a role to play as any small deviation will disrupt the process of ketosis. But, what guidelines must we follow then if going into ketosis is the ultimate goal? Consider these 3 below as they will address each macronutrient properly.
Guideline #1 | Keep Carbohydrate Levels Low
A mandatory guideline here, but how low are we talking? Well, much lower than you probably thought. According to Harvard Health and other research around a ketogenic diet, the number of carbohydrates that you should consume needs to be at or below 50 grams per day in order to be effective [4][5][10]. Therefore, foods like fruits, grains, cereal, and even those higher-carb fat sources like avocado, all need to be monitored closely for dietary success.
Common carbohydrate sources and higher carbohydrate fat sources. As we can see, 50g can add up fast.
Deviating too far above the recommended carbohydrate range is enough to make glucose the primary energy source, while going too far below it may cause unwanted side effects. These may include headache, constipation, and muscle cramps to name a few [11].
Guideline #2: | Keep Protein in Check
As previously mentioned, protein should also be monitored on a ketogenic diet as gluconeogenesis, or the creation of carbohydrates from certain amino acids can still occur. Therefore, regardless of carbohydrates being present or not, certain amino acids can be converted back into glucose by entering what is known as the Citric Acid Cycle or by being converted directly into pyruvate and eventually glucose [1].
Amino acids are located within the purple/red boxes.
Put simply, once enough protein is in your body for systemic recovery and key metabolic processes, consuming any more than this will lead to 2 different fates. One fate being the excretion of any leftover protein from the body and the other being protein that is converted directly into a form of energy [12][3]. This includes glucose, as previously mentioned, as well as fat.
Regarding how much protein to consume, .54g/lb - .7g/lb of protein seems to be a good place to start [6]. Therefore, depending on the person and how active they are on a daily basis, the more or less protein within this range will need to be eaten. The more exercise that you do, especially with weight training, the more protein that you'll need to eat (and vice versa).
Guideline #3 | Remainder Of Calories Come From Dietary Fat
Once carbohydrate and protein intake is taken into consideration, navigating your intake of fat is the last step in this process. A small caveat, however. Total calories still need to be accounted for as eating too many of them, especially from fat, will lead to weight gain and other health issues.
People may often complain of weight gain on a ketogenic diet and this is sometimes the reason why. Oils, butter, nuts, etc. are relatively small in regards to their portion size but come loaded with calories given their high energy density nature. This makes fat easy to over-consume, especially on a ketogenic diet given their abundance.
There are approximately 450 calories in 1/4 cup olive oil.
A Template For You To Follow | Implementing These Guidelines
With this advice in mind, applying these guidelines correctly will be key, as blindly putting meals together may not be the best idea. Cravings, lethargy, and desires to eat more carb-heavy food are likely to kick in initially, but knowing what numbers you should hit from the get-go will help you fight any carbohydrate urge.
Step 1. Calculate Your Daily Calorie Needs
Otherwise known as your TDEE, knowing how many calories that you should roughly consume will be step number one in setting up this diet. This is because knowing how much you should consume from the start will give you the information needed to determine where those calories come from (carbohydrate vs. protein vs. fat). To do this, we can use the NIH body weight planner as a good estimate to go by: https://www.niddk.nih.gov/bwp.
In the physical activity box, select ‘very light’ to obtain one number, and then re-do the calculation with the activity level you think corresponds with your weekly exercise routine. This will be the range of calories you‘ll want to eat as this is only a rough estimate as to what you’ll truly need. For reference, I would say I’m quite active on a weekly basis, however, my calories correspond best to the very light activity calculation: ~2,150.
Step 2. Determine Your Intake of Carbohydrate, Fat, & Protein
Once we know how much to eat, we now have to decide where these calories will need to come from. This can be referred to as “setting up your macros” so to speak given the need to be somewhat strict with them. Because carbohydrates are the food we want to limit, they will be the first nutrient we’ll need to consider. After carbohydrates, we will then set up our protein intake and lastly our fats. See below.
For carbohydrate intake: aim to consume 20g-50g per day and adjust this intake depending on the outcome. More active individuals may be able to consume closer to 50g while those who are less active may want to lean closer to 20g. However, 50g seems to be the upper limit for nutritional ketosis to occur regardless [9]. This equates to 120-200 calories from carbohydrates.
For protein intake: multiply your TDEE by .54 and .7. This is the range you should aim to consume. In the beginning, aim to consume the number that comes out when you multiply your TDEE by .7. Higher protein intakes may come with added benefits in terms of satiety, dietary adherence, and preserving lean muscle, which should be a priority given the scarcity of carbohydrates [17][18][19][20].
For fat intake: consume the remainder of your calories to meet your TDEE. If you want to gain weight, eat slightly over your TDEE with fat calories (250 calories worth). If you want to lose weight, then consume slightly below your TDEE by restricting fat calories (250 calories worth). For health purposes, aim to keep saturated fat low (<10% of your daily calorie intake) while consuming higher amounts of omega-3 and monounsaturated fats [13][14][15][16].
Step 3. Adjust Based On The Outcome.
In terms of adjusting these numbers, specifically from carbohydrates and protein, obtaining either a ketone blood meter or breath analyzer can be something you can do. These will measure the levels of ketone bodies present in either the blood or breath to give you feedback as to where these ketone levels fall. For a ketogenic diet, ketone levels should measure roughly .5-3.0 mmol/L which is the state previously referred to as nutritional ketosis [9]. This range is typically considered safe [20]. If your carbohydrates are being consumed within the 20-50g window, it’s likely your ketone levels will be within this nutritional ketosis range (hence no need to buy a monitor). If this is not the case, take a look at your food consumption and adjust your carbohydrates and protein if needed.
What To Expect On A Ketogenic Diet | False Claims & Why They Aren’t True
After making the commitment to adopt this diet, the first thing people may experience is a decline in energy and feelings of lethargy. Since carbohydrates play a big role in fueling our muscles, brain, and other vital organs, it’s very likely a drop in this macronutrient will cause a shift in how a person feels [21][22][23]. Here are some other common claims that often confuse people around a ketogenic diet.
Claim #1: A Ketogenic Diet Is The Blueprint For Weight Loss
The ketogenic diet is quite useful for weight loss as suggested by dieters who decide to try it. By itself, however, the ketogenic diet is no blueprint for any weight loss effort considering total calories are being considered [25]. Meaning, weight loss will be a direct result of any energy reduction you happen to induce. Therefore, if you expend more energy (calories) than you eat, weight loss will occur no matter the diet.
Claim #2: A Ketogenic Diet Is Good For Anaerobic Activities
Anaerobic activities that include sprinting, weight lifting, or anything similar are best completed with an energy source that supports the anaerobic pathway. This means glucose. Since anaerobic activities take place without oxygen (which means anaerobic), glycolysis, or the breakdown of glucose for energy, occurs as a result (energy labeled as ATP).
Glucose on the other hand is not needed for aerobic activities that utilize oxygen to generate energy. Here, fats are the primary fuel source making the ketogenic diet more supportive of these activities. These activities include lower intensity efforts such as easy jogging, walking, and activities that keep the heart rate below 60% of your maximum heart rate [24]. Anything more intense than this and glucose will start to be used.
Claim #3: A ketogenic Diet Is Good For Longevity.
Diet and longevity is a topic that’s still being researched. However, a slight calorie deficit; a diet rich in micronutrients; and a diet that includes periods of fasting may be indicators of supporting longevity from what we know [26][27][28]. A ketogenic diet, although it can create a calorie deficit quite easily, may miss out on the micronutrient aspect the other diets may offer. Micronutrients typically come from carbohydrates that include fresh vegetables, fruits, and various legumes.
Final Thoughts On A Ketogenic Diet
With the many diets available to us today, the ketogenic diet is in a category of its own. Having more strict guidelines when compared to the others, it is still possible to make this diet work day-to-day. Long term, the ketogenic diet may not be the most lifestyle-friendly as restricting any macronutrient, especially carbohydrates, can be difficult to sustain given their abundance. However, if this is still a diet you may want to try, sticking to these guidelines will be a step in the right direction.
References
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