How does energy flow through your body?

Many people find it difficult to maintain a healthy flow of energy through their body, which has led to a global epidemic of obesity and lifestyle-related disease.

What is energy?

‘Energy’ is a transferable property defined as: The capacity for doing work and/or making heat. Thermodynamics is the branch of science that explains the physical laws governing energy.

The First Law of Thermodynamics states: The amount of energy in a closed system (our entire universe) always stays the same. The energy can change from one form to another, but it cannot be destroyed; and new energy cannot be created.

That means the energy flowing through your body right now has been moving around our universe, in a variety of forms, since the dawn of time.

No energy, no life 

The cycle of life begins with the sun. Plants transform the energy from sunlight into a form that animals can eat (food) or breath (oxygen). 

When you eat plants or animals, energy flows in to fuel your metabolic processes. Some of this food energy is stored inside your body and the rest flows back out to continue the cycle.

When energy changes form, it generates heat. Your body uses the heat generated by metabolism, and other cellular processes, to maintain its core temperature.

Excess body heat is lost to the environment and changes into other forms of energy.

How does energy flow in?

All the macronutrients – Carbohydrates (Carbs), Proteins and Fats – are sources of food energy.

Sucrose (table sugar) is a Carb. When a single Sucrose energy molecule goes into your mouth, it hydrolyses (water is added) and the energy changes into two new molecules called Glucose and Fructose.

These molecules transform into other forms of energy, which are either stored or keep flowing through your body and then out to continue the energy cycle.

Energy storage

It is essential to balance your own energy flow to maintain lifelong health. If more energy goes in than comes out, your body automatically stores the excess.

Excess Fructose energy is stored as fat in your liver. The liver has limited capacity to burn fat for energy and can be overwhelmed very quickly when you eat a lot of sweetened food and drinks.

Glucose energy is stored for a short time (1-2 days) as glycogen in your liver and muscles. Unused glycogen converts to long-term storage (visceral body fat), which collects around your organs (belly) and muscles.

When you follow a low Carb diet, fast* and/or exercise intensely, short-term stored energy will run out and your body will switch to using visceral body fat and excess protein to keep you humming.

*Fasting is not advised for children and teenagers under the age of 16 years.

How does energy flow out?

A small amount of transformed energy flows out of your body as heat, sweat or waste, which transfers energy to the environment, including soil, plants and animals (e.g. bacteria).

However, the majority of energy flows out when you exhale Carbon dioxide (CO2).

Plants convert CO2 to Oxygen (O2) and provide food for animals, which keeps the cycle of life flowing.

You can balance the flow of energy through your body by making wise food choices, exercising daily and building therapeutic fasting into your routine.


Download the ‘Energy Cycle Poster’ and ‘Metabolic Maze’ and use them to explore the concept of energy with a child to help them understand and teach others about how energy flows through their body.


Download the printable A4 flyer for this module.