How to Calculate Calories for Fat Loss

Controlling food portions and making a conscious effort to increase physical activity is essential for long-term weight management.  

In the Western World, it is not like before, when our food supply was scarcer, and people were much more physically active. Today, high-density high-calorie food is cheap and readily available, and most people are sitting at a desk all day working from the office or home.  

This presents a real problem because our natural instinct as human beings when food is available is to overconsume it. In fact, if you put food in front of any animal in the animal kingdom, it will consume it.    

We are wired to eat more than we need at present as a means of storing excess energy in the form of body fat to defend against famine when food is not available.   

Not only that, but these days people eat for reasons other than actual hunger, such as stress, loneliness, boredom, and/or emotional eating.    


Therefore, controlling our food portions purposefully when food is overabundant is an essential skill set that we need to develop. It requires willpower, discipline, and self-restraint to go against our natural instincts.  

So, whether you are reading this as a qualified personal trainer or a health and fitness enthusiast, it is vital to understand this simple yet controversial topic. 


Why Calories Matter for Fat Loss 

Different diets go different ways of restricting food intake. Some diets restrict certain food groups, others restrict entire macro groups, and others restrict food portions.  

Ultimately, all diets work by creating an energy deficit.  



Studies have shown that diets that restrict portions instead of macros tend to have better dietary adherence [1].  

Diets that restrict entire macros or food groups operate under the presumption that you will automatically lower your food intake by eliminating those foods.  

However, that is not always the case. For example, we’ve had individuals following a keto or a low-carb diet plan discover that they were eating between 3,000-4,000 calories a day when they started tracking their caloric intake because they thought they had a free license to eat as many fats as they wanted since they were restricting their carb intake.  

Some fatty foods, such as nuts and cheese, are easy to overconsume if you do not monitor and control your portion sizes. The same goes for ‘low fat’ options disguised as healthy treats packed with sugar and calories. 



Now all of this (and more), we teach to personal trainers and medical professionals through our Performance Nutrition (PNC) Coach Online Nutrition Coaching Certification; click here for more information. 

In closing, irrespective of the diet plan that you are following, we still recommend tracking your calories and portion sizes.  


How Do I Calculate Calories for Fat Loss

Calculating your daily caloric intake can be separated into three simple steps 


Step 1: Calculate Resting Metabolic Rate (RMR) 

Your resting metabolic rate consists of the calories you expend at complete rest. This is the energy needed to sustain life. 

On average, a person burns around 1 calorie per kg per hour at rest. Therefore, if you weigh 60kg (132 lbs), you would burn around 60 calories per hour at rest or about 1440 (60×24) calories daily.

If you want a more sophisticated way of calculating RMR, use the Katch McArdle formula, as shown in Figure 1 below. 

For this formula, you will need to know your lean body mass, which you can obtain using skinfolds, DEXA, or through our partners at Evolt Body Scan.  


Step 2: Calculate Physical Activity Level (PAL) 

Next, you need to factor in your energy expenditure from physical activity. This includes both your exercise and non-exercise activity thermogenesis (NEAT).  


You can estimate your total daily energy expenditure (TDEE) by multiplying your RMR by the appropriate PAL factor from the table below:


determine your NEAT level, use Figure 3 as a guide:

For example, if someone’s RMR is 1400 calories, and their estimated PAL is 1.5, their TDEE will equal 1400 x 1.5, which equals 2100 calories per day. Their predicted daily energy expenditure is based on their RMR and physical activity level. 

Note that this is just an estimate, and if someone has been chronically dieting, their actual maintenance might be quite a bit lower.  

Step 3: Calculate Target Daily Energy Intake 

Once you estimate your daily energy expenditure, you can calculate your target daily caloric intake based on your goal.  

You generally want to set a modest deficit of around 15-25% for fat loss.  

This provides enough of a deficit to force the body to tap into fat stores without risking significant metabolic compensation or muscle loss. It also gives you a little wiggle room if you plateau to drop a little lower.   

For example, if someone’s predicted maintenance is 2000 calories, a 20% deficit would put them at 1600 calories.  


Carnivore, Intermittent Fasting, Low Carb, What Do I Choose? 


As mentioned earlier, every diet works by creating an energy deficit. So, it’s essential to maintain a consistent energy deficit, whichever diet type you choose. However, the diet you will most likely stick to long term will probably work best for you.  

We recommend a balanced diet with a fairly even spread of protein, carbs, and fats. This ensures that you get adequate amounts of each of the essential macro and micronutrients.  

We recommend spreading your calories evenly over 3-5 meals daily.  

For most people, this helps maintain stable blood sugar throughout the day. Eating at regular mealtimes may be more important than how often you eat as your body learns to anticipate food at those times, which helps with hunger and appetite management.  



In conclusion, all diets work by creating an energy deficit in some shape or form. However, diets that restrict food portions instead of food groups generally have a higher success rate.  

Restricting food portions instead of food groups or macros also ensures that you obtain greater macro and micronutrient diversity from your diet, giving you more control of weight loss plateaus.   


More Information 

Enjoy this article and want to learn more about nutrition, reverse dieting and more?  

Click here to access our FREE nutrition course by Dr Layne Norton, nutritionist and body composition expert. 



  1. Dansinger ML, et a. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomised trial. JAMA. 2005;293(1):43.