Nutrition: What are macros and how to calculate them?

Macronutrient Key Facts

4 calories per gram

Composed of amino acids (‘essential’, which the body attains through diet and ‘non essential’ which the body can assemble itself)

Used in our body for growth and repair of cells, increasing muscle mass and in enzymes, hormones, antibodies and neurotransmitters

Aids with satiety, immune function, metabolism, weight management and performance

Protein has a thermogenic effect and can also liberate fat from stores around the body to be utilised as energy


4 calories per gram

Carbs can be classified as simple and complex

Simple carbs are faster to digest and absorb compared to complex carbs

Carbs are the primary source of energy for your bodies cells


9 calories per gram

Three distinct categories, saturated, monounsaturated and polyunsaturated which can be found in unprocessed and wholefoods.

Trans and hydrogenised fats are industrially processed, usually found to preserve foods and increase shelf life of products.

Dietary fat supports metabolism, cell signaling, the health of various body tissues, immunity, hormone production, and the absorption of many nutrients

Improves satiety, body composition, mood and can offer cardiovascular protection

How to calculate your macros

When calculating your macros a good place to start would be to understand exactly how much energy in calories your body would need to maintain at rest, this is called your basal metabolic rate (BMR). To create a more accurate figure of your BMR, it would be wise to understand your body composition and body fat percentages. Body fat percentages can be calculated using skin callipers, although these are more likely to be correct if performed by a trained professional).

The Katch McCardle method for working out BMR is:

P = 370 + (21.6 x LBM), where LBM is the lean body mass in kg.

To workout LBM:

LBM= Body Mass in KG x (100 – Bodyfat %) / 100

Lets take a 100kg athlete with 10% body fat.

LBM= 100 x (100-10)_/100

LBM is 90kg.

BMR= 370 + (21.6x90)

BMR = 370 + 1944

BMR = 2314 Kcal

Now you know your BMR, you need to factor in a few calculations based on your daily activities and of course your training!

Average activity multiples

1.2 Sedentary job (desk job and little exercise)

1.3-1.4 Lightly Active (Light daily activity AND light exercise 1-3 days a week)

1.5-1.6 Moderately Active (Moderately daily Activity & Moderate exercise 3-5 days a week)

1.7-1.8 Very Active (Physically demanding lifestyle & Hard exercise 6-7 days a week)

In the above example our athlete with a BMR of 2314Kcal has desk job but trains intensely 5-6 days a week.

If our above 100kg athlete works in a sedentary office job (category 1.2) but then trains hard 5 days a week (catergory 1.8), it would be sensible to put him in a mid range of around 1.5.

TDEE (Total daily energy expenditure) = 2314 x 1.5

TDEE= 3702 kcals

The TDEE is an estimate of your maintainance calories, which would effectively allow you to retain a constant weight, in order to create a defecit, you can decrease the overall calorie intake, or increase activity levels.

There are other considerations when working out your preferred macronutrient intake. The following table will outline the characteristics of three body types, ectomorphs, mesomorphs and endomorphs. When setting up a nutrition plan, it is important to know your body and understand some key traits that tie into developing an improved physique. For example, if you are an endomorph, starting at a higher body fat percentage and a slower metabolic rate, you may find it useful to understand that due to impaired insulin response or beta cell dysfunction, your ability to utilise carbohydrates may be significantly lower than an ectomorph. Having said that, if you are a trained individual, it could be that your carbohydrate tolerance is actually quite good! These tables are approximates only and in no way should be considered the key to success when creating your own nutrition plan, as you will surely realise by now, what works for one person will not necessarily be right for another.

Somatotype Characteristics Approximate percentage of macro split for each Somatotype 
Protein Carbs Fats
  • Naturally thin with skinny limbs
  • Endurance Exercise
  • Fast metabolism
  • High sympathetic nervous system activity
  • Higher carb tolerance
25% 50% 20%
  • Naturally muscular and athletic.
  • Bodybuilding/ Strength
  • Testosterone and growth hormone dominant
  • Moderate to high sympathetic system activity
30% 40% 30%
  • Naturally broad and thick set.
  • Strength Exercises/ Powerlifting
  • Insulin dominant
  • Slow metabolic rate
  • Low sympathetic system activity
  • Low carbohydrate tolerance
35% 25% 40%

Our 100kg, 10% body fat example could fall into the mesomorphic range. Therefore to calculate protein, carbs and fats you will calculate the following:

Protein= (3702*0.3) = 1110.6 kcals = 277g protein

Carbs = (3702*0.4) = 1480.8 kcals = 370g carbs

Fats = (3702*0.3) = 1110.6 kcals = 123g fats

If you are unable to categorise your body type clearly, there is another simple approach to working out your macros. Consuming between the range of 2-2.2g protein per kg and fats at around 1g per kg body would be within normal ranges for an individual that trains. The rest of the daily calories can be consumed in carbohydrates.

Therefore protein would be 2.2*100= 220g (880kcals) fats 1x100= 100 (900kcals) and carbs would be set at (3702-1780)= 1922 kcals (480g).

Timing and considerations

While cutting your goal should be to retain a positive nitrogen balance and stimulate muscle protein synthesis (MPS). This can be achieved through consuming between 20-30g of high quality sources of protein every 3-4 hours. MPS offers a protective effect against muscle loss, as body fat levels reduce. By retaining a high level of protein in your diet there will be an increased thermogenic effect (calorie output will increase to digest the protein), muscle protection and offer greater satiety.

I am a huge advocate of using carbohydrates within your diet, if you are able to utilise them effectively. Carbohydrates will fuel your sessions, your recovery and also improve your sleep. Carbs have had a bad reputation, because most people tend to either over eat them or tend to consume refined or processed forms, whilst also misunderstanding optimal timing of consumption. I tend to use slower digesting carbohydrates pre workout or through the day and faster digesting carbs post workout.

For some reason dietary fats got a bad rep, then a great rep and then people thought that it would be better to just replace all carbs with fats. Nutrition can be a minefield. Therefore keep it simple, if you have moderate amounts of each macronutrients you will cover all basis for optimal health and function. I keep a healthy level of fat intake in my diet throughout a cut, as they play a huge role in mood, energy provision, increased insulin sensitivity, fat loss and hormone production.

I always start a cut on around 4 litres of water, which for me is quite easy. Others struggle to drink plain water, therefore mixing in Reflex Amino Fusion can have a great effect on not only hydration, but also providing your body with a constant steam of essential amino acids. Consuming enough water can aid in the blood flow from tissues and improve the ability to oxidise fat on a cellular level.

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