How To Be An Efficient Fat Burner Over 50: Understanding Metabolic Flexibility

Metabolic Flexibility to burn fat

To be an efficient fat burner, your body needs to be able to switch from burning glucose to fat as a fuel source. This switching ability is called Metabolic Flexibility. It is the ability for the body to switch between different sources of fuel for energy.

Having metabolic flexibility means your body adapts its fuel source according to the demands placed on it, like exercising or just sitting around, fasting or having just eaten, and yes, even when you’re stinkin’ thinkin’.

An efficient fat burner can adapt and switch proficiently between fuel sources. It’s this adaptation that increases the opportunity for the body to use fat and its fat stores for fuel. Metabolic flexibility increases the chances to have better lipid oxidization, i.e., fat burning.

This fuel-switching adaptation better supports our muscles when we’re moving or doing high intensity work, and with less fatigue.

Why Being An Efficient Fat Burner is Important

Being an efficient fat burner allows you to extract and deliver oxygen to the body. This in turn, allows your body to burn more fat. The more fat you burn, the less fat you have on your body.

Being able to burn fat efficiently is also an indication on how well your body is breaking down and using the nutrients from the foods you eat.

Just think. Your cells are absorbing, digesting, transporting and storing food in such a way that allows your body to switch and use different fuels for energy…on demand.

The speed of your metabolism is affected by your activity levels, muscle mass and several other factors. As a result, metabolic speed varies from person to person.


Fuel stores come in three forms, carbohydrates, fat, and protein. Carbohydrates are the body’s principal energy source.

Carbs turn into glucose which can be used immediately as fuel from the bloodstream, or the body can tap on its stored fuel in the liver and muscle. This stored fuel is known as glycogen.

How much glycogen storage you have is influenced by the type of food you eat and the amount of exercise you do.

The body requires less oxygen to use carbs as fuel than it does with fat and protein. This makes carbs the most efficient fuel for high intensity work .

But carbs can be tricky.

Our marketplace today is loaded with highly refined foods and carbs, where fiber has been broken down and processed. This processing causes the food to be easily and quickly absorbed as glucose in the bloodstream. Insulin rushes in to get the glucose out.

Metabolic Flexibility refined carbs

If there’s too much glucose in the bloodstream that your body can’t use, it’ll store it as fat.

Over time, our cells can’t manage the glucose overload. The cells lose their ability to respond adequately when glucose comes into the bloodstream, and it creates insulin resistance.

Similar things happen when you’re eating multiple meals a day. Because your body becomes reliant on the constant flow of calories, you’re never giving your system a rest. Your insulin levels never have a chance to drop.

Blood sugar levels rise to unhealthy levels leading to weight gain, insulin resistance and type 2 diabetes.


Fat, on the other hand, is the most concentrated form of energy and provides us with twice as much energy as carbohydrates. Transporting fats from the adipose tissue into the working muscles is a much slower process than carbohydrates’ immediate response.

Fat is like having a whole barrel full of quarters when you go to the laundry. It’s almost unlimited as a source of energy. Intensity and workout or activity duration determine how the body’s uses fat as fuel.

Fat requires more oxygen than carbohydrates to burn. As duration of work or activity increases, you’re running out of steam so the intensity decreases. More oxygen is available and then fat becomes the main fuel. Fat assist with energy demand as glycogen stores lower.

When we’re at rest, our bodies are designed to get about 80% of its energy from fat. The remainder energy requirement comes from glucose. For many people, however, the switching mechanism is damaged, and they burn glucose instead.

Not being able to cross over or switch fuel sources efficiently means your body will burn glucose as its main source of fuel. It gets stuck there.

Your body will continue to burn glucose and

it won’t be able to burn fat.

This is metabolic inflexibility, a result of nutrient overload, high carb diet and not enough exercise.

These metabolic shifts can set us up for metabolic syndrome, leading to diabetes, obesity, cancers and cardiovascular diseases.

Fats have negligible effect on insulin, can eat more fat and not spike blood sugar and continue to promote fat burning vs fat storage.

Eating high amounts of fat with very low or no carbs can force the body to burn fat using the ketones from fat as fuel. This type of diet has conflicting evidence as to health outcomes. When it’s time to add carbs back in, this type of diet can impair the body’s ability to use carbs. This also leads to metabolic inflexibility.


Protein can also be used as fuel, and generally occurs much later when glycogen stores fall. You would find this occurrence in long endurance events. The body will break down muscle where protein is stored and process that into glycogen.

Lean muscle protein can be broken down and used as fuel if your diet isn’t adequate in total calories.

How to Become An Efficient Fat Burner for Over 50

Becoming an efficient fat burner over 50 and having metabolic flexibility is more difficult to determine. There are many factors that could play a role.

As we mature, our cells don’t absorb and use nutrients as efficiently as they once did. We also tend towards muscle loss which fuels metabolism. The rate of actual energy processing in our bodies reduces, affecting and reducing metabolism.

General consensus is that our metabolic flexibility will also decline.

But stay with me here…not much research is done on metabolic flexibility for older adults.

And there are things we can do to keep up to maintain, perhaps even improve these some of these factors.

How do we do that? You guess it, diet and exercise. Surprised? Shouldn’t be.

Eating a variety of foods provides an opportunity to eat the rainbow, helps hormones work better and provides various nutrients as fuel sources.

Fasting can also help in establishing metabolic flexibility as it forces the body to use up glucose.

Exercise more often and throw in some high intensity work a few times a week. This helps with being able to switch fuels. Vigorous exercise can require up to 95% of our fuel storage.

Doing more strength training helps build lean muscle mass, increasing metabolism.

Metabolic Flexibility strength training

Exercise requires metabolic flexibility in switching fuels to support the energy demands made on muscles to perform the work.

We should also throw getting a good night’s sleep in there, too, as disrupting our circadian rhythm has far-reaching consequences into our health on many fronts.