26 January 2018 , Posted by Jay Geraghty

Bodyweight in both men and women is controlled by the calories we consume relative to the calories our bodies burns in a 24hr period and is known as our Energy Balance or Calorie Balance (the amount of energy in an item of food or drink is measured in calories). Everything we eat and drink (excluding water) provides our bodies with calories and any exercise we do, whether that’s walking, running, resistance training as well as our daily bodily functions i.e. breathing, blood circulation, metabolism etc burns calories. If we consume the same amount of calories as our body burns in a 24hr period, our body weight stays the same. This is known as our Maintenance level (maintenance meaning our weight doesn’t go up or down, but remains the same).

Every single person will have their own unique daily calorie maintenance requirement which depends on multiple variables such as age, height, weight, gender and activity level. Below is a good starting point for both men and women when trying to determine their maintenance level for my target market.

Maintenance Table

Once we know our maintenance level, by altering either side of the energy balance equation, your body weight will change accordingly.

If we eat ABOVE our maintenance i.e. we eat more calories than we burn in the same 24hr period, we gain weight – AN ENERGY SURPLUS

• The body stores fat in response to a calorie surplus
• Rate of fat gain is generally proportional to the size of the surplus created.

If we eat BELOW our maintenance i.e. we eat less calories than we burn in the same 24hr period, we lose weight – AN ENERGY DEFICIT.

• Fat, glycogen, and muscle can be used for energy to make up the caloric difference.
• Fat loss is generally proportional to the size of the deficit created.

This is the essence of dieting and fat-loss (and gaining, on the other end of the spectrum). When you consume less energy than your body uses daily, it is forced to use some of its stored energy (fat mass, ideally).

It is the ONE single variable that absolutely MUST be present in order to achieve any meaningful tissue (fat or muscle) losses or gains.

A caloric deficit (to lose) or a caloric surplus (to gain).

That now said, in order to lose body fat, we need to create an energy deficit to that of our maintenance level. From experience, reducing your calorie intake by 20% below maintenance, over a 7-day period, is a good starting point and should allow you to lose 1-2lbs of body fat each week – Note: This is an estimation and results will vary from person to person.


If you were required to consume 2000 calories per day (for maintenance), in order to lose a 1-2lbs per week, you would then need to eat 1600 calories per day (2000 minus 20%). By consuming 1600 calories but burning 2000 calories per day, you create a calorie deficit and the body is forced to use its own energy stores, predominantly body fat, to make up the difference.

Deficit Table

Our Energy Balance is defined by the laws of thermodynamics and dictates whether weight is lost, gained, or remains the same. It’s the basic formula for how body weight is regulated in all living organisms, including humans. Physics is not just an idea, it’s the law.

Creating a calorie deficit is the only determining factor in losing bodyfat. It’s how the human body works and is the only way any human has ever or will ever lose weight, it always has been. The higher the baseline FM level of an individual, the more aggressively the caloric deficit may be imposed. The deficit can either be imposed daily (24hrs), and/or over the course of the week (7 Days).

Why Does Fat Loss Stop?

Most people have a tendency to assume that if their maintenance caloric intake is exactly 2500 calories and they eat 2000 calories per day, they should consistently lose exactly fat each week until they reach their goal weight, believing their 2,500 calorie maintenance will never change. Wrong, and here’s why: Your maintenance level isn’t static. It changes.

As your body weight decreases, so does your calorie requirements for energy maintenance – as a smaller body requires less calories. Eventually a new maintenance level will be reached and maintained and your body will no longer be in a caloric deficit. In other words, your body has now caught up and adjusted to the amount of energy it expends, and is able to perform the same activities, but using your lower calorie intake per day. This is why it’s important to always remember the fundamental and only requirement for fat loss – you must consistently REMAIN in a calorie deficit to continue to lose body fat.

Fat loss slowing down or stopping is defined as an extended period (1-2 Weeks) of being stuck at a certain bodyweight. There are only ever two possibilities to why its stopped. They are –

1. Lack of compliance i.e. not keeping your body in a calorie deficit, or
2. A new maintenance level has been reached.

That’s it, nothing else! Fat loss is simple – You create and ‘MAINTAIN’ a calorie deficit for a period time until desired weight is reached – Simple.

When fat loss stops, after the initial deficit has been created, which it will and normally happens between 3-6 weeks for most people, it’s simply a matter of re-opening the deficit with either a further decrease in calorie intake (from food), increase in energy output (exercise), or a combination of both. That’s it. Remember, that maintaining a caloric deficit is the key to fat loss. Before you ever make any changes, be true to yourself, if you haven’t stuck to your plan that week, but decide to remove food or do more exercise, you are only jeopardising your results and make it harder for yourself over the long term.

Jay – The Physique Geek