ExerciseNutrition Weight-Loss. How Does It Occur?


Weight-loss is a tricky subject, that has many approaches, backgrounds, and theories!


Weight-Loss is a tricky subject, that has many approaches, backgrounds, and theories. This has made reliable information in this day and age, very difficult to come across. Each website will tell you something different. Although the quality of information seen is increasing, this can be a mind-boggling task for the average gym-goer to figure out.

I will attempt to explain the most common way of approaching weight loss goals. This is not an expansive guide covering all entities of nutrition, but it will be perfect for helping you understand how weight loss is achieved biologically and systematically. As well, it will help you understand terms such as energy and how it relates to calories/caloric intakes.

How does Weight-Loss work in our body?

We will start off asking, how does weight loss work in the body? Simply put, our body is like a car. Some people are like V8’s and require great amounts of fuel. Others are more like Corollas, requiring little fuel and able to run off of very little. V8’s require higher Calorie Intakes in human terms, calories are our equivalent of fuel.

Figuring out whether how much fuel your body needs can be tricky, and requires trial and error. However it can be relatively accurately modeled through three factors.

1) Your base energy expenditure, or basal metabolic rate. The natural rate at which your body burns calories.

2) Activity Levels of the person. How many calories they burn through activity. Smaller activities like typing, sitting, and breathing are all part of this, but use little calories. The more full-body movements you encounter daily, the higher your Activity Level and the more calories you burn daily as a result.

3) Thermic Effect of food. The usage of calories in the conversion and utilisation of food into energy that is available for ready usage.

Energy Expenditure

A good plan for weight loss must start with calculations around the individual’s energy requirements. This is based on the client’s basal metabolic rate. This is the rate at which a person burns energy or calories, while at rest and while the body is not digesting food. It differs among people, however, not as much as it has been made out to be in popular culture.

Activity Levels

A person’s activity level must also be taken into equation. Someone who is an athlete by trade, or even a busy tradie by trade, will often expend far more energy every day, week and year. Compared to, say, an office worker, who sits down 10/24 hours a day doing work.

This is exactly why it is so highly recommended to walk a minimum of 10000 steps every day. Our output through just this, is enough to both reap the benefits of cardiovascular and health improvements (which in turn could even positively impact your natural resting metabolic rate in its own). As well as greatly increase your energy output for the day. Walking between sets at the gym, or every 50 minutes at work, walking to work, or even getting in a nightly walk can go a long way in burning extra energy when practiced often.

Thermic Effect of Food Consumption

One final common criteria for calculating energy expenditure in a person, is the thermic effect of food consumption. This is the amount of energy it takes to process and utilise food within the body. It can often be estimated as 10% of food energy intake, meaning a person on a 2000 cal diet would spend around 200 calories of internal energy actually processing and using the fuel.

This is a good reason to include Protein into your diet. Protein has a much higher thermic effect, and can actually help with expenditure when used in your diet (protein also has so many other important effects in humans- do not count it out) correctly, as it is more difficult to process than fats for example.

Calculating a person’s energy expenditure levels

As a result of the great differences between people, this number is most easily found using a calculator. This, as you may already be thinking, is not accurate for everyone. Every client must be individually assessed and monitored. In case the number is too high, or too low for the individual, therefore either forcing too much or too little weight loss. These calculations are usually done using a TDEE calculator online. Or performing equations on pen and paper.

Conducting a Weight-Loss Phase

From here, Weight-Loss is theoretically simple. In order to lose weight, your body must have less energy (Calories) than is needed in order to support your TDEE (Total Daily Energy Expenditure) number. You can do this by slowly making reductions weekly or fortnightly, and will require you to consume less food. You can make simple drops in calories by dropping sauces, butters or milks from foods where possible. Or finding alternatives that are lower in calories.

Large drops in calories will require more structure in the meal planning. Hunger becomes more and more evident as you head further and further into your Caloric Deficit. A deficit of calories will have significant effects on energy levels when at the 500+ deficit range. Eg. a person in a 500 calorie deficit who usually consumes 2400 calories would consume 1900 calories. To counter for this, high volume, I suggest low-calorie foods to ensure a more filling meal, with less caloric intake. However, increases in Energy Output are always preferable to dropping calories.


You have now learnt the basics of how weight loss operates in humans and other animals. Do your best to modify your energy output before reducing calories, as this is the easiest and healthiest way to start weight loss. Once a routine of appropriate energy output is established, keep track of your morning scale weight bi-daily or weekly, and if weight-loss is not occuring on the scale, reduce by 200 Calories, and repeat.

Much more however goes into nutrition than simply increasing energy and decreasing food intake. Quality of food, timing of food in some cases, individual health parameters and tests, composition of foods, as well as Macronutrient & Micronutrient intakes are vital in ensuring you are providing your body with everything it needs, regardless of being in a caloric deficit.

Being healthy, does not mean losing weight, it means so much more than this, so when looking to set your goals, make sure you take this into equation and maximise your health in all areas to avoid harmingĀ  yourself in the long run. Contact us, or a coach in order to ensure you have these areas perfect, before jumping into anything blindly.

We all have the power to change our lives and health for the better, it all starts with a choice and a reason behind that choice! as well as the courage to continue in your pursuit, even during the hardest of times and days.

Unlimited Potential PT

Comments are closed