What the science says about ketogenic diets and why they probably won't help you "bother" much.
There are many different food patterns, many of which also have cute names, such as South Beach Diet, Weight Watchers Diet, Atkins Diet, HCG Diet, Volumetric Diet, paleo diet, IIFYM (literally "IfIt Fits Your Macros "-" If It Fit into your KBJU "), carbs-backloading, the ketogenic diet, which we will talk about today.
One of the most used diets is the ketogenic one. Despite the fact that many people use it for fat burning, this diet is surrounded by a lot of misinformation.
Perhaps the most misunderstood aspect of the ketogenic diet is how it affects athletic performance and the ability to gain muscle mass and increase strength.
The ketogenic diet - from the word "ketosis"
Ketosis is a metabolic condition that occurs when the amount of carbohydrates in the diet is so low that the body simply has to use the fatty acids and metabolism of the ketone bodies for energy. It seems that everything is simple, but let's understand this process to understand why our body goes into a state of ketosis.
Our bodies need enough energy in the form of ATP to function.
ATP is a universal source of energy for all biochemical processes in living systems.
A person needs 1800 kcal per day on average (you can calculate your personal rate on a fitness calculator) to produce enough ATP and remain viable. At the same time, the midbrain requires about 400 kcal per day and uses almost only glucose as energy. This means that aperson needs to consume 100g of glucose per day just to maintain normal brain function.
What does this have to do with ketosis? On a ketogenic diet, we remove almost all carbohydrates from our diet, which means we are depriving our brains of glucose. But we need our brains to function somehow. Fortunately, the liver stores glucose in the form of glycogen and can donate a small amount to our brain to keep it functioning. Our liver can store 100-120 grams of glucose on average. With a severe lack of carbohydrates for brain functioning, the liver allows us to function normally throughout the day. Eventually, however, the liver's glucose stores cannot be replenished quickly and carbohydrates aren't just needed by the brain, which is why we have problems.
Our muscles are also a huge store of glucose: they contain 400-500 grams of glucose in the form of glycogen stores.
However, glycogen stores are not primarily designed to feed the brain. Unfortunately, our muscles cannot break down glycogen and enter it into the bloodstream to power our brain, due to a lack of an enzyme in the muscles that breaks down glycogen (glucose-6-phosphate dehydrogenase).
In the absence of carbohydrates, the liver starts producing ketone bodies which are transported through the bloodstream to our brain and other tissues that do not use fat for energy.
Let's quickly examine the biochemistry of these processes. When you "burn fat, " the fatty acid molecules in your body are converted into acetyl-CoA, which in turn combines with oxaloacetate to start the Krebs cycle.
During ketosis, our liver uses so much fat as energy that excess acetyl-CoA starts producing ketone bodies (beta-hydroxybutyrate, acetoacetic acid and acetone).
Gradually,with a regular carbohydrate deficiency, the body reaches such a state that this process begins to occur constantly, and the level of ketone bodies in the blood increases dramatically, so we can say that we are officially in onestate of ketosis.
What is a ketogenic diet and how does it differ from a "low carb" diet
A low carb diet and a ketogenic diet are not the same thing.
The low carbohydrate diet uses fat and carbohydrates for our daily energy needs. Our body does not store ketone bodies in the blood and our tissues do not use ketones for energy.
With a ketogenic diet, our body reaches the point where ketone bodies are produced in large quantities and used as fuel. During such diet-induced ketosis, beta-hydroxybutyrate levels can be between 0. 5 and 3. 0 mM / L. You can even purchase blood ketone test strips and measure your own.
A low-carb diet limits the amount of carbohydrates in the diet (often just under 100 grams per day), but beta-hydroxybutyrate levels do not reach 0. 5 and 3. 0 mM / L.
How to eat on a ketogenic diet
As we discussed above, the ketogenic diet should be high in fat and low in carbohydrates.
In traditional and strict ketogenic diets, 70-75% of the daily calories should come from fat and only 5% from carbohydrates. The amount of carbohydrates you can consume while in ketosis varies from person to person, but you can usually consume up to 12% of your calories from carbohydrates and remain in ketosis.
Protein intake is also very important. Most athletes have made it into their heads that they need to consume large amounts of protein, perhaps this is one of the factors in unsuccessful ketogenic diets.
As we discussed earlier, theprotein when consumed in high doses can be broken down into glucose (during gluconeogenesis) and therefore it is not possible to enter ketosis.Basically, if you consume more than 1. 8 grams of protein per 1 kg of body weight, this amount will be enough to get you out of ketosis.
Ideally, to improve your ketogenic state and maintain lean muscle mass, your diet should be around 75% fat, 5% carbohydrates, and 20% protein.
"Adaptation" phase in a ketogenic diet
If you read the literature on ketosis, you will notice a general trend. There is the most characteristic "adjustment" phase where people experience a clouded mind, feel sluggish and lose energy. Basically, people feel very sick in the first few weeks of a ketogenic diet. This is probably due to the lack of essential enzymes in our body, which are needed to efficiently oxidize certain elements.
To survive, our body tries to rewire itself to use other energy resources and learn to rely only on fat and ketone bodies. Usually, after 4-6 weeks of adapting to the ketogenic diet, all of these symptoms disappear.
Ketosis and athletic performance: a review of scientific research
Let's take a look at some studies that might answer this question.
Study n. 1The first study involved 12 people (7 men and 5 women, aged 24 to 60 years) who followed a self-prescribed ketogenic diet for an average of 38 days. Subjects performed moderate to intense training, blood counts, body composition, and maximum oxygen uptake were measured.
The same study authors conclude: "The radical reduction in carbohydrates did not statistically show a significant effect on running performance, judging by the time the subjects began to fatigue and the level of maximum oxygen consumption, butbody mass composition improved, participants lost 3. 4 kg of fat and gained 1. 3 kg of lean muscle mass. "
Therefore, study participants lost weight, but showed no noticeable changes in athletic performance. Additionally, the subjects decreased the body's ability to recover.
Study n. 2Another study involved 8 men in their 30s with at least 5 years of training experience. The subjects followed a 4-week mixed + ketogenic diet and did prolonged workouts on stationary bikes at varying intensities.
The ketogenic diet also had a positive effect on body mass composition, as in the first study.
Interestingly, the relative values of maximum oxygen consumption and oxygen consumption at the anaerobic threshold increased significantly with the ketogenic diet. The increase in maximum oxygen consumption can be explained by a decrease in body weight. However,the maximum workload and the workload at the anaerobic threshold were lower after the ketogenic diet.
This means that theketogenic diet resulted in weight loss, but also a significant decrease in explosive strength and the ability to train at high intensity. Do you want to be stronger and train more? So don't assume the ketogenic diet is a good choice for this.
Study n. 3The third study examined how a 30-day ketogenic diet (4. 5% calories from carbohydrates) affects performance in the following exercises: hanging leg lifts, push-ups on the floor, push-ups on parallel bars, pull-ups, squat jumping and 30-second jumps. The scientists also measured the body composition of the participants.
Here are the conclusions:
- The ketogenic diet caused a "spontaneous reduction in calorie intake" compared to the normal diet.
- No loss of performance was found with the ketogenic diet tested, however, no performance improvement was found.
As with other studies, there was a noticeable difference in body weight composition after the ketogenic diet: participants were able to lose weight. It should be borne in mind, however, that the participants selected for this study were already quite dry (about 7% body fat).
It is also important to remember that none of these tests considered the glycolysis process as a source of energy, they were more tests that tested explosive strength, phosphagen system and muscle fatigue tests.
Study n. 4In this study, 5 experienced cyclists performed the maximum oxygen consumption test and the time to exhaustion (TEE) test before and after a 4-week ketogenic diet.
As this research is quite lengthy, I want to focus only on the performance aspect and muscle glycogen levels. The TEE test showed a huge difference between the participants. One subject improved TEE scores by 84 minutes in 4 weeks, the second showed a 30 minute increase, while two subjects decreased by 50 minutes overall, and one subject remained unchanged:
Regarding muscle glycogen stores, a muscle biopsy showed thatglycogen stores after the ketogenic diet were nearly half of normal. This fact is already enough to say that you can say goodbye to high performance.
Research results on ketogenic diets
Let's take a look at what these 4 studies have in common:
Improved body composition.Each study resulted in a qualitative improvement in body composition. However, it is a controversial fact that this is the miraculous effect of the ketogenic diet, rather than spontaneous calorie restriction. Because if you research any type of diet and body composition, any diet that restricts calories improves body composition.
In the third study, subjects consumed an average of 10, 000 fewer kcal in 30 days (minus 333 kcal per day! ) than on a regular diet and, of course, lost weight.
It is likely that the ketogenic diet may still offer additional benefits in terms of changes in body composition, but research has yet to prove this.
It should also be mentioned that there is no literature to support the idea that a ketogenic diet can help build muscle. It only helps to lose weight.
- Decreased performance with high intensity loads. The first two studies showed a decrease in the subjects' ability to exercise at high intensity. This is possible for two reasons: first, a decrease in intramuscular glycogen and second, a decrease in hepatic glycogen stores during high intensity training.
- Reduction of intramuscular glycogen stores. Decreased athletic performance during high-intensity training is a sign of decreased intramuscular glycogen levels, studies have shown. It can also negatively affect the recovery of athletes who train and the ability of muscles to grow in size.
Mistakes made by people on ketogenic diets
Although there is no clear advantage over conventional calorie restriction, ketogenic diets can be a good tool for losing weight. If you are looking to lose weight (maybe even through muscle mass) then maybe you should try it. Now let's take a look at the mistakes people on ketogenic diets often make to avoid making them.
Lack of an adequate adaptation phase
Switching to a ketogenic diet can be very difficult for some people. Most often, people abandon the diet during the adaptation phase without completing it. The adaptation phase can last for several weeks, during which weakness is felt, consciousness becomes clouded, but after 2-3 weeks the energy levels return to normal.
If you want to try a ketogenic diet, give yourself plenty of time to adjust.
Eating too much protein
As we have already learned, too much protein can prevent ketosis. People often substitute low-protein carbohydrates with a ketogenic diet - this is a mistake.
Using a ketogenic diet under high intensity exercise
For high intensity anaerobic exercise, our body relies primarily on glucose stores in the blood, liver and muscle glycogen, and gluconeogenesis.
Since ketogenic diets reduce muscle glycogen levels, it is very difficult to train with high loads.
If you want to train at a high intensity, try a carbohydrate diet instead of a ketogenic diet.
Ketogenic diets prevent muscle gain
Ketogenic diets can help you lose weight, but not increase muscle mass.
CD will prevent you from training at high intensity and gaining lean muscle mass, so if these are the goals you are pursuing in your training then it is best to give up on the idea of practicing CD.
Consuming proteins and carbohydrates together produces a greater anabolic effect than consuming these nutrients alone. On a ketogenic diet, cut back on carbohydrates. And because you need both carbohydrates and protein for optimal muscle growth, you are missing one or both of these key nutrients.
Conclusion: Ketogenic diets are neither optimal nor effective for muscle building and athletic performance enhancement. However, they can help you lose weight, just like any other calorie restriction below your personal daily value.