Intermittent Fasting and the Ketogenic Diet - Part 1

Previously we talked about intermittent fasting/time restricted eating and how you could apply it to your current type of diet for enhanced health and physique goals. 

Today, I want to begin a series on the ketogenic diet with you. We'll talk about how it shares many similarities with an intermittent fasting style approach, and whether or not a ketogenic or intermittent fasting style approach is best for you.

You may have heard of the ketogenic diet, often called the keto diet, or simply keto. The keto diet is a specific type of very low carbohydrate diet (VLCD).   

While the keto diet maybe be very low in carbohydrates, not all VLCD’s are ketoegnic.

This is a very important distinction, because the ketogenic diet is specifically formulated to encourage the production of ketone bodies, which are commonly referred to as ketones. Ketones are the by-products of the body breaking down fat for energy in a very low carbohydrate environment. This process is done naturally when fasting.   

The ketogenic diet was originally designed to mimic the effects of fasting. 

In fact, the ketogenic diet was originally created by doctors in the 1920s in order to mimic the therapeutic effects of fasting to aid in the treatment of patients with seizure disorders. This is due to the neuroprotective effects that ketones provide.

In recent years, the ketogenic diet has been gaining in popularity, first in fitness circles. and most recently, with mainstream America. 

Most people aren’t looking into a keto diet for its ability to mimic the therapeutic effects of fasting, however, they are looking into a keto diet because they believe that it will make them lose weight. And while it is true that you can lose weight successfully on a keto diet, it may not be for the reasons that you think. 

The common thinking behind a keto diet for fat loss is that it puts your body into a fat burning state called ketosis. Ketosis occurs when you're in a very low carbohydrate state and there's inadequate glucose from carbohydrates to fuel your bodily tissues. 

Your body begins to transform fatty acids freed form your fat cells into ketone bodies, which can then be burned for fuel in place of glucose (from carbs) by many of your bodies tissues.   

One thing that is often overlooked is that even in a state of ketosis, your liver will manufacture glucose to meet the minimal demands that your body has for glucose. So even in a ketogenic state, your liver will manufacture glucose. This is done to ensure that your muscles have glycogen, the glucose fuel required in order to function.  

Remember that keto mimics fasting. The muscles need glucose in order to function so in the absence of carbohydrates the liver will manufacture glucose. This is a survival mechanism built in to humans to allow us to fight to defend ourselves, or to have the strength to hunt prey after days of fasting.  

This is especially important for strength athletes, or for those who maximum performance is a must. 

While it is true that the liver will manufacture glycogen for the muscles to use for fuel, it can not and will not manufacture enough for optimal athletic performance.

If optimal performance at sport or the gym is your primary goal, then a ketogenic diet may not provide you will the raw fuel that your muscles need. [1] 

We have established that once in a state of ketosis, your body is now burning primarily fat in the form of ketones to meet its energy demand.  Burning more fat for fuel, sounds great right? But it's important to remember that in a fasted state, 100 percent of the fat that you are burning is coming from your bodies stored fat. Makes sense right? If you eat no food, the only fat you can burn is from stored fat.

In a ketogenic diet, however, you are eating large amounts of dietary fats. So while it's true that your body is “burning fat for fuel,” you are also eating fats to provide fuel. 

This is a key point because what this means is that even in a “fat-burning state of ketosis," you will not lose weight unless you eat fewer calories than you burn. 

For weight loss, maintaining a caloric deficit is an absolute must - it's the primary determinant in how much weight you will lose. 

When compared to a traditional low-carb diet, ketogenic diets have been shown to confer no additional metabolic advantage. Meaning, if your calories between the two diets are the same, then the weight loss will be as well. [2]

Even when compared to a higher carbohydrate diet, the ketogenic diet did not result in greater weight loss as long as calories between the two diets were matched. [3]

If it isn’t better for weight loss, then why do it?

I have fasted intermittently for nearly ten years, and have done a strict ketogenic diet for 6 consecutive months. My primary driver behind adopting these types of eating plans was to harness the variety of powerful health benefits that ketones provide. 

Below are just a few of the documented health benefits of ketones:

1) Ketones have neuroprotective benefits. They have been shown to block amyloid, a kind of plaque that builds up in the brain in Alzheimer’s cases. [4]

2) Ketone bodies protect agains dysfunction in the mitochondria. [5] 

Our mitochondria are responsible for generating 90 percent of the energy that we and our cells need to function. In addition to this, the mitochondria are responsible for regulating apoptosis (programmed cell death). This is the process by which the body recycles damaged cells. 

Unregulated cell growth can lead to diseases such as cancer. Research is showing that mitochondrial dysfunction is a factor in many chronic diseases. Ketones exert an antioxidant effect within the mitochondria, which prevents the damage that can lead to these diseases.

3) Ketones have mood-boosting, stabilizing, and anti-depressive properties. [6] [7]

The brain can switch to using ketone bodies for fuel. Emerging research suggests that this may lead to improvements in mood, depression and mental state. This is what's responsible for the mental clarity, energy, and focus that individuals report once they have hit a certain point during a fast, or after they've been on a ketogenic diet for a few days.

Ketones provide special heath benefits, not weight loss benefits.

The main health benefits to a ketogenic diet are derived from ketone production. A ketogenic diet has not been shown to result in more weight loss than other diet types, as long as calories are matched. 

So what are the drawbacks? It's a very restrictive diet. Eliminating carbohydrates entirely is not realistically sustainable for most people. 

If you want the balance of increased ketone production while still having dietary flexibility, intermittent fasting offers the best of both worlds so to speak. 

Remember, the keto diet was designed to mimic fasting. Our bodies naturally produce ketones when in a fasted state. When you wake up from an overnight fast, your body is already making some ketones. The longer that you extend your fast, the more ketones your body will produce. 

If you have questions about how you can benefit from increased ketone production through intermittent fasting or a ketogenic diet, I would love to hear them! 

-Jerry Teixeira

[1] Ketogenic diet benefits body composition and well-being but not performance in a pilot case study of New Zealand endurance athletes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506682
[2] Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets https://academic.oup.com/ajcn/article/83/5/1055/4649481
[3] Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men https://academic.oup.com/ajcn/article/104/2/324/456464
[4] Ketones block amyloid https://www.ncbi.nlm.nih.gov/pubmed/26923399
[5] Ketones Inhibit Mitochondrial Production of Reactive Oxygen Species Production Following Glutamate Excitotoxicity by Increasing NADH Oxidation https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1865572/
[6] The ketogenic diet may have mood-stabilizing properties https://www.ncbi.nlm.nih.gov/pubmed/11918434
[7] The antidepressant properties of the ketogenic diet http://www.ncbi.nlm.nih.gov/pubmed/15601609