Watch the Carbs, Don't Fear the Fat!

brain health healthy eating healthy living real food sugarfree May 26, 2024

When you ask people what their favourite source of energy is, they will likely name some kind of carbohydrate.  This could be bread, pasta, potatoes, a grain such as rice or quinoa, or even a chocolate bar!  No matter what form they come in, they will all be metabolized in your body into glucose–or fructose when it comes to fruit.

Sugar and its many forms, so common in our high-carb diets, are a major health problem.  Diseases such as diabetes are almost non-existent in cultures which have not been exposed to our fast, highly processed, sugared foods. 

One of the reasons sugar can be so dangerous is because of a process in the body called Glycation, producing advanced glycation endproducts, or AGEs, which damage the brain.  AGEs are brown, sticky compounds that prevent the body from working properly, that are created through a chemical reaction between protein and sugar in the presence of heat.  When the body has an unnaturally high level of sugars, the heat generated by normal body activities promotes this reaction, just like the caramelization reaction a cook will look for when heating sugar and cream to turn it into candy.

Glucose is the simplest form of carbohydrate, the final end product when we eat complex carbohydrates, and is one of the preferred fuel sources (the other is fat) for our brain, organs and working muscle. 

But how much and what kind of carbohydrates should we choose?

Strategy #4 - Watch the Carbs, Don't Fear the Fat!

The Glycemic Index

The glycemic index or GI is a popular concept used to determine the effect of certain carbohydrates on blood sugar levels in the body. It therefore represents the metabolic response of the body to the carbohydrates we eat.  

Foods that have a low GI do not raise blood glucose levels as much, nor as fast as foods that have a high GI.

Glycemic Load

The main problem with using the standard GI is that it only accounts for the type of carbohydrate and not the amount. Therefore, the glycemic load or GL was introduced to represent the glycemic index adjusted for the amount of carbohydrates, thus representing the quality and quantity.

The higher the GL, the greater the expected increase in blood sugar levels. 

The GL is calculated by multiplying the GI of a food by the grams of carbohydrates per serving size. Therefore, foods with a greater amount of protein, fat or acidity, will help blunt the glucose response, improving blood sugar levels.

The Glycemic Load of a food can be classified into 3 groups:

  • Low GL = <10
  • Medium GL = 11-19
  • High GL = >20

Click HERE for a table that shows some of the common foods that their respective glycemic load.

Don't Fear the Fat!

Any carbs consumed in the diet that are not immediately used, will be stored in the body as fat.

That means there’s another source of fuel for your body, one that for many years we were led to believe would be harmful:  Fat and Ketones

This isn’t surprising, given the demonization of fat that has occurred over the last 70+ years, and with widespread marketing of low-fat products, low-fat diets that seem to be commonplace nowadays. 

A lot less attention is directed toward the widespread evidence that supports, nay recommends a regular intake of fats in a healthy diet. 

The Critical Role Of Fats

Fat plays multiple, essential roles in the body – meaning that those following a “low fat” diet may not be getting enough for their essential needs!

  • Energy source
  • Major component of cell membranes
  • Appetite suppressant
  • Key player in managing inflammation
  • High in nutrients such as fat-soluble vitamins A, D, E and K

Fat is required for optimal cell function, and is a structurally integral part of every single cell membrane within the body.

Fat as an energy source

In the absence of Carbohydrates our bodies flip from using glucose (and storing fat), to using that stored fat and ketones (made from fats) for fuel The ability to flip what our bodies use as fuel (between glucose and ketones) is called “metabolic flexibility.”

It’s thought that we, and many animals, evolved to have this ability to survive short periods of fasting from when we were hunter-gatherers. There were times when people didn’t have a lot to eat, but they still needed to survive and think clearly enough to successfully hunt and gather food. This can explain why our bodies and brains don’t necessarily become sluggish when we’re fasting. It makes a lot of sense, although it has yet to be tested in current-day hunter-gatherers.

Intermittent Fasting

This metabolic switch can explain some of the health benefits of fasting. When our bodies prefer using fats for fuel, the body starts burning our stored fat. This is how Intermittent Fasting (IF) helps with overweight, obesity, metabolic syndrome, and type 2 diabetes. When the body uses fat for energy this decreases the amount of fat in the body. Reduced stored fat reduces weight, and health benefits from weight loss (like lower blood pressure and insulin resistance) are felt.

This “flipping” of the metabolic “switch” happens after the available glucose is depleted. This is anywhere from 12-36 hours from the last meal, depending on the person. At this point the fats in our cells start getting released into the blood and are metabolized into ketones. These ketones then go on to fuel the cells with “high metabolic activity” - muscle cells and neurons. 

Since the body is burning fat and using ketones to fuel the muscles, fasting can preserve muscle mass. Some studies of IF show that it preserves more muscle mass than regular calorie reduced diets do. 

The other high metabolic activity cells fueled by ketones are neurons (in the brain and nervous system). IF helps our brains because when our neurons start using ketones for fuel, it preserves brain function and increases brain-derived neurotrophic factor (BDNF) which is very important for learning, memory, and mood. BDNF also helps enhance synaptic plasticity (changes in our brain that help with learning and memory) and allows our neurons to better resist stress. These are all improvements in brain function, and some animal studies also show improvements in the structure of the brain too. For example, new neurons are produced in the hippocampus (the part of the brain important for short- and long-term memory) in animals who IF.

Plus, according to Patrick Holford in Upgrade Your Brain: 

Your brain loves ketones, derived from fat, and runs better with a supply of both glucose and ketones. Ketones are made in the liver, most directly from a kind of medium-chain triglyceride called C8 oil. Studies giving two tablespoons of mainly C8 oil to those with declining memory have brought their brains back to life, producing over 200 per cent more energy from ketones. You can buy C8 oil, often derived from coconut oil, and add it to foods and drinks. Pure ketone esters and salts are used by some to rapidly increase the brain’s supply of ketones. Giving your brain a break from carbohydrates and going ketogenic for a while helps repair it.”


  • Watch your Carbs
  • Choose low GL carbs, and avoid those that are highly processed.
  • Don’t Fear the Fat
  • Choose healthy, natural fats from both plant and animal sources
  • Consider Intermittent Fasting to “flip the switch” from glucose to fat as your source of fuel 
  • Give your brain a break from carbohydrates and go ketogenic for a while to help repair it.


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