There are loads of different energy calculations, we have selected the Mifflin one, as it personalises the calorie target based on characteristics of an individual (sex, age, height, weight, activity level). This means it’s more personally tailored to you.

Your daily energy or calorie needs, should be based on how much muscle you have, and how much you move. A calculation to determine how much muscle mass you have, is more difficult to accurately determine, but everyone should be able to fill in the information that this calculation requires.

A couple of critical points with this: This is not a starvation diet plan. Statistically the optimal energy deficit number, for long term sustained weight loss, is 20%. If you go on a bodybuilders shred week diet or some swim suit diet plan, they may give you a 50% deficit, which will definitely give you results, but that plan, and those results won’t be sustainable. But, because the plan is so drastic, if you make a few mistakes and over eat a few times, you may still be in a deficit, and lose some weight.

As this plan is designed to be sustainable, and only has a moderate deficit number, it shouldn’t leave you starving and de-pleated of energy. However, you can’t afford to make as many mistakes, as that can bring you up to your maintenance level, where you won’t lose weight. So, you should test regularly (with a recorded weekly weigh in) and adjust things (nutrition and/or training) accordingly, based on your results. You only have two variables to manipulate, training and nutrition. You can lose weight without doing any training, but that’s not going to get you healthy, fit, or strong with an athletic physique. So once you’ve decided on the type and number of training sessions you’re going to do. If you stick to your nutrition targets, don’t lose weight, and aren’t prepared to increase your training sessions. Then you need to make modifications via your nutrition and drop your calorie targets slightly.

Once you get the right result, which should only be a 1% loss of your body weight, per week (again – this is a statistical long term weight loss target number). Record the correct calorie target and how many sessions you did, and you have your winning recipe. It can take a few goes to get this right, but once you’ve got it, you’ll no longer be guessing or hoping for the result, you’ll have a lot more control over it.

I’m not a huge fan of calorie counting for every meal, what I recommend is: Do a few counts on normal meals you would generally eat, and set them up calorie specific to your target numbers. Record this (which can be a simple as a written breakdown you leave on your fridge, phone or diary, or even a simple picture), then you should be able to more accurately guestimate other similar meals based on your calorie counted ones.

My most successful weight loss clients, are always the ones that put the work into getting their nutrition right. Training is about building your ideal physique, improving health and performance, weight loss is about getting you calories right!


Enter the following info into the blanks:
  • Gender, Age, Weight, Height, Activity factor
  • Then select an energy deficit for weight loss (I recommend going for 20%), or go for the slight energy surplus option for building muscle. There is a maintenance option too.
  • Once you have your calorie target, enter how many meals you want to split that total over, and you’ll have your meal target number.

    Then it’s simply a matter of making your meals up to those targets, and testing your result at the end of each week, to ensure you’re getting the result you’re after.


    Estimated Calories Kilojoules
    Per day
    Per meal
    Sedentary - Little to no structured excerices 1.3 1.3
    Light 1.5 1.5
    Moderate 1.8 1.7
    Heavy/Aggressive 2.1 1.8

    There are 4.2 kilojoules per calorie. Divide kilojoules by 4.2 to get calories or times calories by 4.2 to get kilojoules.


    To lose 1 kg of fat it is necessary to achieve a 28,700 KJ (7000 calorie) deficit.


    According to exercise physiologists Victor Katch & Frank Mcardle, the average female between the ages of 23 and 50 has a maintenance level of about 8820 kilojoules per day (2100 calories), and the average male about 11,760 kilojoules per day (2800 calories).


    American College of Sports Medicine (ACSM) recommends that calorie levels never drop below 5040 kJ (1200 calories) per day for women or 7,560 kJ (1800 calories) per day for men. Even these calorie levels are quite low (Venuto 2012). ‘Of the calculations tested the Mifflin standard provided an accurate estimate of actual resting metabolic rate in the largest percentage of non-obese and obese individuals’ (Frankenfield 2003).   Using the Mifflin equation, resting metabolic rate can be accurately predicted in about 80% of nonobese and overweight people and in about 70% of obese people (Frankenfield & Ashcraft 2011)


    Frankenfield, D, Ashcraft, C 2011, Estimating Energy Needs in Nutrition Support Patients, Journal of Parenteral & Enteral Nutrition, vol. 35, no. 5, pp. 563-570

    Frankenfield, D, Rowe, W, Smith, S & Cooney, R 2003, Validation of several established equations for resting metabolic rate in obese and nonobese people, Journal of the American Dietetic Association, vol. 103, no. 9, pp. 1152-1159.

    Body fat rating scale men women
    Competition Shape (“ripped”) 3-6% 9-12%
    Very Lean (excellent) < 9% <15%
    Lean (good) 10-14% 16-20%
    Average (fair) 15-19% 21-25%
    Below average (poor) 20-25% 26-30%
    Major improvement needed (Very poor) 26-30%+ 31-40%+

    High body fat levels have been linked to over 30 health problems including diabetes, high blood pressure, cardiovascular disease, cancer and osteoarthritis. Being categorized as “clinically obese” means that body fat is at such a level that these health problems become more of a concern. Men are considered borderline at 25% body fat and clinically obese at 30%, while women are borderline at 30% and clinically obese at 35% body fat.


    Essential body fat is 2-3% for men and 7-8% for women.


    With few exceptions, most women who try to maintain their body fat levels at or below 10-13% can have problems with estrogen production, their menstrual cycles and reproductive systems become disrupted and bone density may decrease, putting them at higher risk of osteoporosis as they grow older.

      Reference: Venuto, T 2012, Burn the fat feed the muscle, What is the Necessary Body Fat Percentage to See Your Abs?, viewed 20th August 2015,