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Metabolism and your Weight Loss

How do you Lose Weight and Keep it off?

If you missed our last article on Weight Loss Vs Fat Loss, click here.

If you're ready for the next part, let's dive back in!

If we were to narrow down all the Biological, Environmental, Social aspects of Weight Loss, there appears to be one major determinant of your Fat loss potential, your Metabolism.

What is Metabolism?

Metabolism is simply a chemical process that occurs within a living cell. It is a process that breaks down substances to produce energy. It is also responsible for our overall body composition.

Of all the thousands of metabolic processes that run, we can only directly change and influence a select few. The most common form of measurement is your Basal Metabolic Rate (BMR).

What is BMR?

Your Basal Metabolic Rate also known as your Resting Metabolic Rate (RMR) is the amount of Energy expended while at rest. It is responsible for vital organ functionality such as the Heart, Lungs and Brain.

Your BMR also typically represents about 45-70% of your overall Daily Energy Expenditure. [1] Leaving us with about 30-55% remaining for use in Daily Energy Expenditure.

Metabolism and Weight Loss?

This leads us to perhaps one of the most sought out questions, "Why am I Not Losing Weight?".

In short our body maintains a narrow range of weight via dietary and environmental conditions. This is done by both altering our food intake and by changing our metabolism. Most in particular the rate of burning body fat through a process called 'thermogenesis'.[2]

Whilst there are many variables determining/deterring your weight loss, lets breakdown how your Metabolism responds to Weight Loss:

When calories are restricted, our metabolism slows down within a 24 to 48 hour period. It also continues dropping by about 15%-30% regardless of the body weight of the individual. [3]

Part of the slowing of metabolism when we diet is also due to a loss of metabolically active body tissue (+/- 15%) by the same mechanism. This incompletely understood mechanism by which this metabolic change occurs appears to have to do with changes involving the muscle tissue.

What does this look like?

When eating excessively and gaining weight, both basal metabolism and the energy cost of exercise increase to help burn off extra calories and slow down weight gain.

The reverse happens when we restrict calories, to help slow down weight loss. A result of this process is that after starving ourselves, we gain weight very rapidly when we resume normal eating patterns.

An example would be decreasing how much Energy (Calories) you're currently consuming:


Dropping from 2000 calories to 1500 calories would cause body fat to burn at about i.e. 40 grams per day. This rate would slow down to 20 grams per day by the end of the second month. By the third month it has slowed down considerably to 10 grams per day stopping altogether soon after.[4]

Similarly, after temporary overeating, we lose weight very rapidly when we resume normal eating. Another result of this process is that it is generally impossible to maintain a reduced weight while eating normally. Following weight loss, our energy expenditure is reduced, allowing us to gain weight on less food.

This is one of the main causes of the infamous "dieter's plateau" resulting in people giving up on their weight loss program. Now that we have a rough idea on how weight loss affects the metabolism, we can plan further ahead.

Past Transformation

Checkout this successful and awesome transformation by a past client:

Before Vs After Vs After-After

"When I first started training 2 years ago I wanted to lose weight. I have achieved that. Now, I am focusing on gaining a lot of lean muscle which has been my focus for the last year. I have achieved this but, I still could not lose the last lot of stubborn fat on my stomach. It wasn't really bad I know but I train every day and I felt like i' not getting anywhere with my stomach and I have heard its because I eat a lot of sugar LOL. Tbh I never worried about counting Macros and Calories until I met Franz.

In only a few weeks of shifting to fat loss and counting I was able to start seeing results! I couldn't believe it! Thank-you so much Franz! I couldn't have done it without your help! I really want to just inspire others to change their lives as I have! You've got to simply go for it though! My hope is that my story can help inspire others! I'm aiming to put on a few more kilograms in the next 6 weeks and really bulk then shred as I want to compete next year!" - Lauren.

How do I Lose Weight Successfully?

- In order to Lose Weight Successfully we firstly need to be consuming enough calories for our BMR and Daily Energy Expenditure.

- Secondly we need to start consuming slightly lesser calories but still enough for our BMR and Daily Energy Expenditure.

- Dieting down on as many Calories possible will put you in a prime position going forward as your metabolism adapts and Weight Loss stalls.

- Giving yourself adequate time is also another determining factor of successfully Losing the weight and keeping it off for good.


Weight Loss isn't overly complex. The solution is rather a simpler one.

If you're having trouble Losing Weight, click here.

If you're looking for further concepts on Nutrition and more on the science of Fat Loss, checkout my latest eBook:

Includes a BONUS chapter on how to Calculate your Macronutrient and Calorie Requirements!


1. Cruz, Franz. Eating For a Purpose: Basic Concepts on Nutritional Value (2015) - Energy Consumption. Energy Requirements, p13.

2,3. Todd I. Stark, The Concept of a Body Fat SetPoint (1998) - The "Body Fat Set-Point": Can it be changed permanently? page 4 & 5.

4. Keesey, Richard E. (1980). "A Set-Point Analysis of the Regulation of Body Weight," in Stunkard, Albert J., Obesity. W.B. Saunders Co.

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