The Keto Diet

Introduction to low-carb dieting

Low carbohydrate dieting has gained traction throughout the fitness industry over the last decade, but it's scientific basis stretches back over a century. While there are many "branded" low carbohydrate diets, such as Atkin's, South Beach, Paleo etc, there is one method in particular that is receiving the most attention (and the most scientific backing): The Keto Diet. To be more specific, Keto isn't a branded diet, rather it is a metabolic state in which your body uses molecules called ketones for energy as opposed to glucose. The premise of this type of eating is, "eat fat to lose fat." 

Is Ketogenic dieting the same as other low carb diets? 

Low carb diets are considered to provide less than 50% of your daily calories from carbs. Meanwhile, keto diets are considered very low carbohydrate diets and should provide less than 50g of carbs per day, or about 5-10% of your daily calories. In other words, you can be low carb dieting without ever touching ketosis. 

What is a Ketogenic (keto) diet?

A keto diet is a very low carb diet (also called a Very Low Carbohydrate Keto Diet, or VLCKD), where the body produces ketones in the liver to be used as energy instead of carbohydrates. Although all keto diets are low carb, that does not mean that all low carb diets are keto. 

When you eat something high in carbs, your body will produce glucose and insulin. Glucose is the easiest molecule for your body to convert and use as energy, so it will be chosen over any other energy source. Insulin is produced to process the glucose in your bloodstream by taking it around the body. Since glucose is being used as your body’s primary energy source, fats are not needed, and are therefore stored. Typically, on a normal, higher carbohydrate diet the body will use glucose as the main form of energy.

By lowering the intake of carbs significantly, the body is induced into a state known as ketosis. Ketosis is a natural process the body initiates to help us survive when food intake is low. During this state we produce ketones which are formed from the breakdown of fats in the liver.

The end goal of a properly maintained keto diet is to force your body into this metabolic state. We don’t do this through starvation of calories, but through starvation of carbohydrates. Our bodies are extremely adaptive to what you put into it – when you overload it with fats and take away carbohydrates, it will begin to burn ketones as the main energy source.

Traditional "Western" diets tend to be high in both carbohydrates and fats. With this type of eating, glucose is our body's primary fuel source. When we eat something with carbohydrates, blood glucose levels rise which triggers our pancreas to produce insulin. Insulin shuttles glucose into our cells and we receive energy. In a high fat, low carb ketogenic diet, glucose levels fall and an enzyme called lipase releases stored triglycerides in our fat cells. These fatty acids travel to our liver where they are transformed into ketones. Ketones are then used by our cells to produce energy. So our body switches from using glucose for energy to ketones for energy. 

Ketogenic dieting is not the only way to be healthy, rather it is an alternative for people who are having trouble sticking with a diet that works long-term. We know that more traditional diets that feature high carb, low fat and moderate protein diets work, but may be hard to maintain. This type of high carb, low fat eating does increase strength, endurance and athletic performance. However, we have also discovered that a high fat, very low carbohydrate and moderate protein diet can do the same. The typical "Western" diet of high fat and high carbohydrates is what we need to avoid because this type of eating leads to weight gain, diabetes, heart disease and cancer. Research shows us that fat is not the enemy and carbohydrates are not the enemy, rather it is the combination of both fat and carbohydrates together that should be avoided. 

This graph shows that if you drop your carbohydrates down to about 100g per day, you will have small amounts of ketones in your bloodstream for about a week or two before your body adapts and stops using fats for fuel. This is where most "low carb" diets will keep you. However, if you drop your carbohydrates even lower to about 60g per day you will be able to be in moderate ketosis for the first several weeks, then mild ketosis for the duration of the diet. If you drop your carbs even further to about 30g per day you will enter a deep state of ketosis and stay there, which is ideal. 

What do I eat? 

To start a keto diet, you will want to plan ahead. That definitely means having a viable diet plan. What you eat really depends how fast you want to get into a ketogenic state. The more restrictive you are on your carbohydrates (less than 15g per day), the faster you will enter ketosis. Normally, anywhere between 20-30g of net carbs is recommended for every day dieting – but the lower you keep your glucose levels, the better the overall results will be. 

A net carb is your total daily carbohydrates, minus the total fiber. For example, a cup of broccoli has 6 grams of carbohydrates and 4 grams of fiber. So your net carbs for 1 cup of broccoli is 4 grams. In this diet, you will track both gross carbs and net carbs. 

  

Your nutrient intake should be something around 70% fats, 25% protein, and 5% carbohydrates.

You want to keep your carbohydrates limited, coming mostly from vegetables, nuts, and dairy. Don’t eat any refined carbohydrates such as wheat (breads, pastas, cereals), starch (potatoes, beans, legumes) or fruit.

Dark green and leafy is always the best choice. Most of your meals should be a protein with vegetables, and an extra side of fat. Chicken breast basted in olive oil with broccoli and cheese. Steak topped with a knob of butter and a side of spinach sauteed in olive oil. If you’re finding yourself hungry throughout the day you can snack on nuts, seeds, cheeses or peanut butter to curb your appetite.

While a true keto diet uses about 75% fats, 20% protein and only 5% carbohydrates, some variations of this diet exist, consisting of about 70% fat, 20-25% protein and 5-10% carbs. However, in order to remain in ketosis, carbohydrate intake must remain very low, protein intake must remain moderate and fat intake must remain very high. The reason we keep protein intake moderate is due to the fact that when protein intake is too high, your body will be forced into gluconeogenesis, a metabolic state in which your body converts protein into glucose. When this occurs, ketone production is blunted. 

But fats are bad, right? 

There is lots of established research that shows us how "high fat" eating is bad for you, however, nearly all of the research that examines high fat intake does not control for carbohydrate intake as well. In fact, this research actually confirms the belief that it is a combination of high fat and high carbs that produces negative effects. When we control for carbohydrates and only focus on high fat, low carb eating, the research shows great promise in terms of the health benefits associated with this type of eating. High fat, low carb diets can decrease body fat, preserve muscle mass, decrease the risk of diabetes, heart disease and cancer, and lower both blood sugar and cholesterol. 

Isn't a high fat diet bad for cholesterol?

Traditionally, we have been told that high fat eating leads to high cholesterol. However, it is important to understand how cholesterol works in your body. Cholesterol is transported by molecules called lipoproteins. There are 5 different kinds, but the ones we hear the most are HDL (high density lipoprotein), LDL (low density lipoprotein) and VLDL (very low density lipoprotein). HDL, referred to as "good" cholesterol, is beneficial because it removes cholesterol that accumulates in the bloodstream. LDL and VLDL, referred to as "bad" cholesterol, is not desirable because they can be easily damaged by free radicals and tend to deposit cholesterol in the arteries, causing inflammation and clots. The goal of a healthy individual is to increase HDL and decrease LDL and VLDL while also increasing the size of the lipoprotein molecules themselves. The larger the size of a LDL and VLDL molecule, the less susceptible they are to damage from free radicals. 

Research has shown Keto diets increase the concentrations of heart healthy HDL cholesterol more than low fat, high carb diets. We also find that keto diets not only decrease LDL particle concentration (LDL-C), but also increases the size of the LDL molecules (called LDL-P). VLDL concentration also decreases on a keto diet. Overall, very low carb dieting will increase the "good" cholesterol and decrease the "bad" cholesterol, which is the opposite of what most people assume would happen!

When are ketones produced? 

Ketones are only present in the blood when carbohydrates are severely restricted. In this graph, we can see that blood ketones are definitely present during a 12 week keto diet, but not in a typical high carb, high fat Western diet. 

How long does it take to get into ketosis once I stop eating carbs? 

Once you cut your carb intake your body will use the remaining stored carbohydrate in your liver and skeletal muscles. The average person will store 25,000-30,000 calories worth of glucose, and these stores must be depleted before we can start using ketones for energy. The amount of time it takes for this to occur is highly variable and is based on how much you are restricting carbohydrates and how much glucose you have stored. It may take several weeks to sufficiently deplete glucose stores and start using ketones. Some individuals notice a drop in energy as these glucose stores are getting depleted. However, once you switch to ketones your energy will return to normal, and many people report having more energy than they have ever had before. 

After your body has adapted to using fat for fuel instead of carbohydrates (a process we refer to as keto adaptation), energy levels return. In this graph, highly trained cyclists were able to actually increase their performance time to exhaustion after keto dieting for 6-weeks. 

How are the results? 

When compared to a Western Diet ("WD" in the chart above), individuals on a Very Low Carbohydrate Ketogenic Diet (VLCKD) lose significantly more body fat even though dietary fat intake is significantly higher. 

Very low carbohydrate diets can also spare muscle mass more than higher carbohydrate diets. Without exercise, dieting will not only cause your body to lose body fat, but also lean mass as well. The higher your carbohydrate intake is while dieting, the more susceptible you are to lean muscle loss (as indicated in the chart above). The more you restrict your carbohydrates while dieting, the more lean mass you can keep. This is ideal for keeping your metabolism high. Keep in mind, though, that these results refer to dieting without exercise. But what happens when we keto diet and exercise? 

When resistance training is combined with keto dieting, we actually observe an increase in lean muscle mass, so it is possible to build muscle and lose body fat at the same time while ketogenic dieting. 

Benefits of a Keto Diet

• Cholesterol. A keto diet has shown to improve triglyceride levels and cholesterol levels most associated with arterial buildup.
• Weight Loss. As your body is burning fat as the main source of energy, you will essentially be using your fat stores as an energy source while in a fasting state.
• Blood Sugar. Many studies show the decrease of LDL cholesterol over time and have shown to eliminate ailments such as type 2 diabetes.
• Energy. By giving your body a better and more reliable energy source, you will feel more energized during the day. Fats are shown to be the most effective molecule to burn as fuel.
• Hunger. Fat is naturally more satisfying and ends up leaving us in a satiated (“full”) state for longer.
• Acne. Recent studies have shown a drop in acne lesions and skin inflammation over 12 weeks.
• Physical Performance and Keto Dieting

You may see some limitations on your performance when you first begin a keto diet, but as your body fully adapts to using fat as the primary source of energy – all of your strength and endurance will return to normal. This process typically takes about 2 weeks. As your body uses up all of your remaining carbohydrate stores for fuel, you will begin to feel sluggish. After your body adapts and switches energy systems from using carbs to using fat, you will immediately feel your energy return. 

Your glycogen stores can still be refilled while on a ketogenic diet. A keto diet is a great way to build muscle, but protein intake is key here. It’s suggested that if you are looking to gain mass, you should be taking in about 1.0 – 1.2g protein per lean pound of body mass. Putting mass on may be slower on a ketogenic diet, but that’s because your total body fat is not increasing. 

Precautions and Risks of Keto Dieting

There are a lot of misconceptions about low carb and keto dieting or high fat eating in general which has caused an overall negative outlook of dietary fats. However, extensive research conducted over the last 30 years shows the benefits outweigh the risks. And with more research being conducted in the last 5 years than in the previous 30, we can expect to see more positive benefits of high fat, low carb dieting being revealed in the near future. 

People normally get this confused with high fat and high carb diets, which are terrible for the body. Of course when you eat a lot of fatty foods that are high in sugar, you’ll be getting yourself in trouble. It’s not the high fat that is bad for us (nor is high carbs, for that matter). Rather, it is the combination of both high fat and high carbs that ruins the human body. 

As a precaution, you should always check with your physician if you have any concerns about starting a keto diet. You should especially be weary if your family has any pre-existing kidney or diabetic conditions – as the higher intake of proteins will put strain on your kidneys.

High cholesterol, high blood sugar, and heart disease is not something you need to worry about. High fat, low carb diets are well-known and documented for their improvements in cholesterol, blood sugars, and reduction of heart disease.

What happens to the body when going Keto?

Your body is used to the simple routine of breaking down carbohydrates and using them as energy. Over time the body has built up an arsenal of enzymes ready for this process, and only has a few enzymes for dealing with fats – mostly to store them.

All of a sudden your body has to deal with the lack of glucose and increase in fats, which means building up a new supply of enzymes. 

As your body becomes induced into a ketogenic state, your body will naturally use what’s left of your glucose. This means your body will be depleted of all glycogen in the muscles – which can cause a lack of energy, and a general lethargy. In the first few weeks, many people report headaches, mental fogginess, dizziness, aggravation and occasionally flu-like symptoms (Called the “keto-flu”). However, not everyone will experience these effects and they are all temporary. 

Most of the time, this is the result of your electrolytes being flushed out, as ketosis has a diuretic effect. Make sure you drink plenty of water and keep your sodium intake up. In fact, you should go overboard with the salt – salt EVERYTHING! This will help with water retention, and help replenish the electrolytes.

For a normal person that is starting a ketogenic diet, eating 25-40g of net carbs a day, the total adaptation process will take about 2 weeks. You may notice that if you’re an avid gym goer, you lost some strength and endurance. This is normal. Once your body becomes keto-adapted, your body will be able to fully utilize the fats as its primary source of energy. Many studies done have shown that there is no long term drop in performance for professional athletes on a very low carb ketogenic diet. Many also report more energy at sustainable levels throughout the day.

What does the future of keto research look like? 

While still in its infancy, research into the benefits of ketones beyond weight loss and physical fitness are being explored. Ketone bodies have signaling functions that inhibit histone deacetylases and control gene transcription. By increasing acetylation with ketones, we may be able to regulate genes that prolong the life of cells within the body, which means ketones may have "anti-aging" properties. 

Ketone bodies also increase serum beta-OHB levels in the brain which enhances memory function and may eventually be used to treat cognitive disorders such as dementia and Alzheimer's disease. Keto diets have already been used with success in individuals suffering from epilepsy and Parkinson's disease. 

Very low carbohydrate dieting may also help fight against certain types of cancer. Cancer cells survive off of glucose and by depriving the body of carbohydrates, cancer cells "starve" and may die off. This method may also be used to prevent cancer cells from forming in the first place, reducing the risk of developing certain cancers. 

Clinical recommendations

Long term ketogenic dieting can be used effectively for overall weight loss and other health and fitness related goals. Keto dieting will decrease body fat mass and increase lean muscle mass when combined with proper exercise. The optimal way to approach a keto diet is to cycle keto with low carb dieting every 3 to 6 months. Keto dieting with a slow transition to low carb then moderate carb dieting may be the best available long-term ketogenic cycle strategy.