How And When We Store and Burn Body Fat

Storing body fat

Fat loss is not the most important, nor is it the most crucial part of health and fitness. It is however, the topic most people are interested in; the reason people get back into fitness every January for their New Year’s resolutions. If you are reading this because you either want to burn fat faster or have been unsuccessful so far in your fat loss goals, this will be a worthwhile read.

In simple english we will discuss when and why your body stores and burns body fat. I am a firm believer that if you don’t fully understand the reasons behind things, you will be less likely to stay motivated and succeed in your goals. Similarly to watching a sport you don’t understand, you will often lose interest or want to do something else before the game is over.

Am I Burning Fat Now?

Technically we are always burning some amount of both fat and glucose at all times. The ratio of fat to glucose burned is negotiable. The amount of fat we store on our bodies at any given time is also negotiable. You might argue that it’s different for everyone and I would agree with this statement but, there are unchanging core principles when it comes to fat.

“Focus on the things you can change and let go of the things you can’t.” – Unknown Author

Without understanding what fat is and when or why your body makes the decision to burn it, you can’t ever really spot the problems keeping you from burning fat. Sure, anyone can follow a pre made nutrition plan but, sometimes a nutrition plan falls short of your specific needs. Only the person with an understanding can know how to make alterations to it and be successful. So if you want to burn fat, learn about fat!

Storing Energy for Later

When you eat food, especially carbohydrates, it is converted by your body to glucose. Glucose is a fuel that your body runs on. When you eat carbohydrates insulin is produced to push the glucose into cells that require the energy. If you eat a lot of carbohydrates and produce more fuel than your body currently needs, the extra glucose is converted into fat stores for later.

Insulin moving glucose into cells

Even protein eaten in excess can create additional glucose through a process called gluconeogenesis. The one macronutrient we eat that does not make us fat, (counterintuitively) is fat. Eating fat does not create adipose tissue (body fat) as it is not turned into glucose by any bodily processes. We get fat when body fat is created by pushing excess glucose into cells.

More about the negative affects of glucose on your health here, in the post; “Metabolic Syndrome – What Actually Causes Heart Disease and Diabetes Also learn the differences and health concerns for the two types of fat your body stores. (Subcutaneous and Visceral fat)

Fat Adaptation

As mentioned earlier, you are always burning some ratio of glucose and fat. We have 2 different modes of fuel utilization that drastically changes where your calories are being burned from. One is for burning majority from glucose (Glucose Adapted) and one for burning majority from fat (Fat Adapted).

“Ketone bodies are formed by ketogenesis when liver glycogen stores are depleted” – [2]

We only switch into a fat adapted fuel burning state when glucose supplies are restricted for an extended period of time. The body won’t burn fat unless it is sure there is no other option first, and will even burn muscle (protein converted to glucose) for a bit before dipping into fat stores full on. This body function is how we survived long periods without carbohydrate rich foods. Agriculture has ensured an abundance of carbohydrate rich foods all year round, meaning the average first world individual spends little to no time in a fat adapted state.

Fat Adaptation Diagram

If the glucose supply is restricted for long enough, your body switches from primarily burning glucose to primarily burning ketone bodies. 

Ketone bodies – “are three water-soluble molecules that are produced by the liver from fatty acids” – [3]

Ketones are a fuel source that can be used almost interchangeably with glucose for a majority of your body functions. (In some cases like the heart, it is a preferred fuel source.) The signal for your body to go back into a glucose adapted state is simply the reintroduction of an unrestricted glucose supply. Usually an amount of dietary carbohydrates that is beyond the threshold specific to your own metabolism. The signal that tells your body to stop burning fat is the insulin hormone created to clear the excess glucose from your blood. So, if you eat a type or amount of food that spikes your insulin, you will be taken out of fat adaptation immediately with no wait period.

“Well that sucks!” You might say, but remember this process used to be, and still is a survival mechanism for long periods without glucose based food supplies. This explains why it’s so difficult to burn fat. Knowing all of this will help you formulate a plan for tapping into this system. And if fat loss is your goal then you definitely want to tap into this system. During exercise you can see in excess of twice as many calories burned from fat when fat adapted.

“Peak fat oxidation was 2.3-fold higher in the LC group” – The FASTER Study [1]

The infographic above is the best way to visualize the way your body works if your goal is burning fat. Although the body is always burning a certain percentage of both glucose and fat at all times, it’s important to know the process at which you can change your primary fuel to fat and how easily you can lose that fat adapted state.

Calorie restricting diets that only pay attention to the calories in, calories out model, don’t cut it when our goal is fat loss. They don’t take into account that carbohydrate restriction is needed to prevent glucose and insulin spikes that are counter productive to our fat loss goals. These spikes cause us to continually have to go through the muscle burning stage to get into fat burning. This is less than ideal since the muscles are our engines, and the bigger the engine you have, the more fat you can burn. And if we are burning glucose and muscle, we are not burning fat. We want to spend as little time as possible in the muscle loss zone.

What to Do

In the future there will be links to different approaches to fat loss in this section. For now I will leave you with a few tips and you will have to sign up for the email newsletter in the right hand column of this page for future updates.

Fat Loss Tips:

  • Try working out first thing in the morning when glucose is low and you are closest to fat adapted.
  • High intensity workouts burn more glucose than fat, so consider working out at 60% intensity, as this seems to be the sweet spot for fat burning.
  • Consider removing all sugar and high glycemic index foods from your diet.
  • Remove the majority of starches and grains from your diet.
  • Move all the remaining grains and starches in your diet to your post workout meals when you actually need refuelling.
  • If not working out, limit grains and starches to just one meal a day and exercise moderation with your portion sizes.



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Note: If you read something in this article that you whole heartily disagree with based on scientific empirical evidence, please share it with me here. I’m always interested in appending and updating my information to be as accurate as possible for my readers.

Also contact me if there is anything you would like me to expand on or write about as it applies to your personal situations.


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