Like Maths? Calories and Macros for Fat Loss 101- made simple!


There is so much information out there these days, it’s hard to know what fad to believe.

What is better?

  • Low Carb

  • Paleo

  • Low Fat

  • Mediterranean

  • Keto

  • Carnivore

  • Plant Based

  • Vegan

Ahhhhh! It’s so confusing!! With all this information and all these theories of which diet is best for fat loss and good health, no wonder people give up easily. Make sure whatever you listen to or read is actually science-based, with published peer-reviewed studies to back it up. Dr Google and Netflix documentaries are most probably not.

I like to keep it simple- EAT REAL FOOD. If you are not sure of what this means, it is fruit, vegetables, natural dairy, meat from animals, whole grains, legumes and drinking water. This is also the most beneficial for longevity and good health. If you have an allergy or sensitivity to one of these foods, then eliminate it from your diet- easy…and move on. You can still add in “fun foods” occasionally to your diet, just not every single day- and plan it in, so you know what you are going to have and when.

If you want to lose fat for good health, appearance and for improving your body composition, then basic nutrition knowledge is power. You don’t need to overthink things or worry about “superfoods” and spend big bucks on supplements.

The number one focus is to create a calorie deficit and stick to it over time. Boring, I know!

There are 5 main principles to construct a diet for maximum results in fat loss, performance and body composition in regards to nutrition. These are in order of importance:

1. Calorie Balance -50% (this is the main point and what you should be focusing on first)

2. Macronutrients – 30%

3. Nutrient Timing – 10%

4. Food Composition- 5%

5. Supplements -5%

Calorie balance is the amount of calories you consume versus expend every day. If you are hypocaloric for the day, it means you used more calories than you took in. In every single studied instance (and according to the 3 laws of thermodynamics), a hypocaloric diet leads to tissue loss, which is usually a loss of fat tissue, but it can be muscle tissue as well. If you consistently run a calorie deficit for days and weeks on end, the weight loss will become detectable on the scale and visible on your body.

Calorie balance accounts for 50% of the success of any diet. The single biggest factor in fat loss is whether you have a calorie deficit. If you do not eat enough food to meet all your body’s needs, it uses body fat to meet the shortfall in supply.

The second most important principle is macronutrients- roughly 30% of diet success. I am referring to protein, carbohydrates, and fat.

A quick overview:

  • PROTEIN – Protein molecules are specific arrangements of amino acids. Proteins in the form of enzymes facilitate all important functions in the body, including cellular transport, forming body structures, constructing most of the nervous system AND the most important function is that protein is the building block of muscle tissue. If building muscle or maintaining muscle is your goal, then protein is of primary importance- it literally constructs muscle and helps build and repair. Protein has approximately 4 Kcals per gram of energy.

Around 1g per pound of goal bodyweight is a good place to start in determining how many grams of protein you need per day.

  • CARBOHYDRATES – While protein is the single most important building block of muscle tissue, carbohydrate is the single most important source of energy. Carbs are the best and most preferred source of energy for athletic and high intensity activities. Carbs are also the primary refuelling source of recovery from activities you just did. The most dominant source of carbs for high intensity work is stored in the muscles (and liver) in the form of glycogen. Glycogen is a giant molecule of glucose packed together, and glucose molecules are broken off it to be used for energy. Taking in carbs after hard training replenishes stores of glycogen and allows you to recover and train hard again. Carbohydrate has approximately 4Kcal per gram of energy.

Recommended Carb intake for activity level

“Sedentary” 0.5g per pound of goal body weight

“Light activity” 1.0g per pound of goal body weight

“Moderate activity” 1.0g-1.5g per pound of goal body weight

“Hard activity” 1.5g-2.0g per pound of goal body weight

  • FATS- Fats are utilized by the body to form important hormones, to construct parts of all cells (especially those of the nervous system), and to insulate and cushion our joints from the constant pounding they receive from hard training. Fat also has a high satiety level- a little goes a long way. Fat has over double energy of both carbs and protein at 9 Kcals per gram.

I’m not going to elaborate much on nutrient timing – although if you are an athlete or fitness enthusiast then keeping most your carbohydrates around your training time is optimal, this maximizes performance and recovery.

So how do you calculate your calorie deficit? Firstly, check in with yourself that you are ready, willing, and able to commit to 6-12 weeks of dieting to make the change. If the answer is yes and you have worked out your “why” to refer to when it gets hard (and it will), then let’s get started!

Calculate your energy needs (calories) based on your goals and activity and multiply by your goal bodyweight in pounds.



Lightly active

(<3 hours/wk) x 10-12


Moderately active

(3-7 hours/wk) x 12-14


Very active

(>7 hours/wk) x 14-16



For example if I was 65kg = 65x 2.2 (143.3 lbs.). Multiply my weight in kg by 2.2, to get my weight in pounds (lbs.).

And I wanted to lose 5kg, my goal body weight would be 60kg = 132.3 lbs.

I trained 6 days a week at moderate intensity for at least an hour. Then using the table above, I would multiply my goal body weight by 14. Start with the higher number and monitor for at least 2 weeks to see if this is working:

132.3 x 14 = 1852 calories per day

I suggest go for the higher end (you can always drop back after a few weeks of monitoring if the scale is not moving down). And later when your body adapts and you start to plateau that is when you change the calories to move down, so then multiply by 13, then lastly towards the end of the diet multiply by 12 (for moderate training).

In regards to macronutrient split a balanced approach is the easiest to maintain- this could look like a 40/30/30 split of carbs, protein and fats- you can play with these ratios a little if you prefer more fat to carbs- but at least keep protein 30% at a minimum to maintain muscle mass while losing body fat.

For example for me on my 1852 calories per day this would mean:

40% carbs = 1852 x 0.4 = 741 calories from carbohydrates

This equates to (741/4) = 185gm of carbohydrates per day (1g of carbs = 4 Kcal)

30% protein = 1852 x 0.3 = 556 calories form protein

This equates to (556/4) = 140gm of protein per day (1gm of protein = 4Kcal)

30% fat = 1852 x 0.3= 556 calories from fat

This equates to (556/9) = 62gms of fat per day (1gm of fat = 9Kcal)

So, my Macronutrient split (if I’m counting macros) for my calorie deficit of 1852 Kcals per day is:

Carbs- 185gm

Protein – 140gm

Fat- 62gms

If I preferred more fats to carbs and I wasn't training as much then my split could be 30% carbs, 30% protein and 40% fat. It is up to you.

You can split this throughout the day according to your preferred eating method- anywhere between 3-6 meals per day. I prefer 4-5 meals, but this is totally your choice. You can measure it’s effectiveness over time by scale weight (weigh in twice weekly but graph it from month to month), if your weight has a downward trend you are on the right track- don’t change anything! If it has an upward trend or maintenance and you are following your calories honestly (not only 5 days on and 2 days off), then recalculate the calories using the table – use the lower number.

It is completely normal to feel a little hungry on your diet!

After 12 weeks maximum it is then a good time to have a diet break and what I mean by this is to sit in maintenance for 1-3 months. Maintain your new body weight (you will need to adjust your calories up a little per day -somewhere between 250-500 Kcals per day) and keep monitoring (using the scale) again over the month. Your body will need time to adjust to it’s new “set point” of weight. If you do not do the maintenance, most likely you will go back to where you started. The maintenance is the most important part- anyone can lose weight, but keeping it off is the challenge!

If this is all too confusing, I offer nutrition coaching to make your life simpler and constant support to keep you on track to reach your goals. Feel free to email me for more details.

Thanks for reading, stay strong and enjoy the journey!


Precision Nutrition V4 The Science and Practise of Macros, by Dr John Bernadi

Renaissance Periodisation- Renaissance Women (Fat Loss, Muscle growth and Performance Through Scientific Eating, by Dr Jen Case, Dr Melissa Davis and Mike Isratel

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