Last updated on August 19th, 2018
Ketogenic diets and very low carb diets are not new, but they are in vogue, and it’s important to understand what following one means for your physical and emotional health.
“Low carb” diets don’t really have defined parameters. Many people assume that it refers to the more junky kind of carb rich food – high in sugar and low in nutritional value.
Donuts, cakes, white bread, white pasta, potato…those kind of foods. Those are examples of empty carbs more than anything. Reducing your consumption of them is just common sense.
Carbohydrates are actually abundant, and include food groups ranging from the simple, fast, processed-sugar-laden junk to fruits and vegetables. Sugars and starches come in different packages and forms, but they all fit in the general category of “carbohydrates”.
The definition of “low carb” is perhaps best described using a Ketogenic diet as an example, and then expand from there.
What is a Ketogenic Diet?
Ketogenic diets rely on the formation of ketone bodies in the liver. These ketone bodies are often simply referred to as ketones, but the context is important if this is the case because “ketones” actually describe a lot of molecules.
There are 3 ketone bodies: acetoacetate, beta-hydroxybutyrate and acetone. The latter – acetone – is the product of breakdown of the two former ketone bodies. They are actually water-soluble chemicals, but “ketone bodies” will suffice.
The liver makes these three ketone bodies when blood insulin levels are low and blood glucagon levels are high.
This can be intentional, caused by very low carbohydrate intake (less than 50 grams per day), and unintentionally during starvation or through diabetes.
Nutritional ketosis, i.e. the intentional kind, is known as Ketogenic Dieting.
Carbs are your body’s primary source of fuel. When it has none left, it looks to fat to get its energy.
Fatty acids are released from fat cells and transported around the body to sites that need energy. Fatty acids cannot however be used by the Central Nervous System because they can’t cross the blood-brain barrier.
Ketone bodies can cross the blood-brain barrier and can therefore be used as fuel in the absence of glucose.
In fact, ketone bodies can be used by any cell with mitochondria for use as fuel.
Can Ketogenic Diets Cause Weight Loss?
They can, but only for the same reason any diet is able to: calorie restriction. By reducing carbohydrate consumption enough to trigger ketosis, people are usually eating less calories than they burn over the course of a day.
This is the primary reason for weight loss: Energy Out > Energy In.
One thing to consider is your ability to resist carbs at such a drastic scale. If you are constantly unhappy doing it then you will either remain so for as long as you can, or you will “break” and end up eating carbs, and possibly over-eating.
As with any weight loss diet, sustainability is the key. I try to advise a healthy, rounded diet that is 400 to 500 calories below your Total Daily Energy Expenditure (TDEE). That way you will likely feel less hungry (or downright crappy), you will be able to keep it up, and you will see the success.
Are Ketogenic Diets Healthy or Unhealthy?
If there’s one type of diet than can be defined as “low-carb”, it’s definitely ketogenic diets. Your liver knows pretty precisely what this means because when you eat under 50 grams of carbohydrate a day, it starts to build ketone bodies to replace glucose in your brain and central nervous system.
Think about what that means for a second. It means greatly reducing your vegetable and fruit intake, and it means losing all the whole food nutritional value that comes with it.
There are less extreme low-carb levels. The liver’s maximum storage capacity for glucose is roughly 150 grams, so eating less than that qualifies your diet as “low-carb”, while also allowing you to eat some healthy foods.
Intermittent fasting – where you eat regularly for a day and then fast for a day, or eat regularly for 5 days and then fast for 2 (the 5:2 diet) – is another way to trigger this process, albeit not constantly.
There are health benefits to intermittent fasting. Early evidence suggests life-extension may even be an advantage [https://www.ncbi.nlm.nih.gov/pubmed/24440038] of fasting because it can trigger some regenerative processes. Strong evidence in humans is still way off though.
Some people find intermittent fasting an easier way to lose weight. After all, they just eat normally when they do eat, and then simply don’t eat for a given time period.
Sometimes, simplifying things helps and avoids all the measuring and counting that is often the downfall of diets.
As for ketogenic diets, and what is essentially an permanent state of intentional fasting, the jury is still out.
There are many products available that has associated themselves with the Keto process such as Pruvit Keto Reboot