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Being able to implement an effective nutritional strategy is of the utmost importance for any personal trainer, but especially those working with clients with weight loss targets.

While some PTs work exclusively towards helping others drop the pounds, the market is far too big for any to ignore completely.

Energy balance is the single most important factor for weight loss and in theory is simple. But in practice both personal trainers and the general public often struggle to bring things together for optimal results.

Below is a simplified version of the ‘tool kit’ I have used with great success for my own clients with weight loss orientated goals.

Food diary

Weightloss happens when the body burns off more than it consumes. It’s as simple as that. But before you can work out how much you should cut out to ensure your burn more, you must first establish what is being put in. To do this, keep a food diary and count the caloric content of everything that goes past your lips for seven days. The results may be surprising and act as an eye-opener. The process of keeping a food diary will also help to make you aware of the nutritional content of what you eat which is important for a well-balanced nutritional plan.


An accurate calculation of your basal metabolic rate (BMR) is required to compare how your current daily average sits with what your body actually needs. Your BMR estimates how many calories you would burn in 24 hours if you did nothing but rest. It is the minimum amount of energy required to fuel processes vital for survival. There are a number of ways calculate your BMR, but I recommend using the Mifflin-St Jeor method:

  • Men: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5
  • Women: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161

Activity level & weight maintenance

Along with critical bodily functions, your body also burns energy through movement. The more active you are, the more calories are required to fuel your body. Multiplying your BMR by the figure which most accurately describes your activity levels will give you the number of calories required for weight maintenance.

  • Sedentary (no exercise) x 1.2
  • Lightly active (light exercise 2-3 times per week) x 1.375
  • Moderately active (moderate exercise 3-5 times per week) x 1.55
  • Very active (exercise 5-7 times per week including high intensity work) x 1.725
  • Extremely active (daily intense exercise and/or a very physically demanding job) x 1.9

Note the difference between the calories you should be consuming to maintain your weight and your existing daily caloric intake. If you are overweight, you will most likely be consuming a surplus.

Create the deficit

By creating a caloric deficit you provide your body with less energy than it needs. Your body will make up this deficit by using your fat stores as fuel. This will gradually reduce the amount of fat on your body which in turn will improve your body composition and reduce your overall weight. To calculate how many calories you should consume during a deficit, multiply the number of calories for weight maintenance by the most appropriate rate of fatloss.

  •             Low intensity (10% deficit) x 0.90
  •             Moderate intensity (20% deficit) x 0.80
  •             High intensity (30% deficit) x 0.70

Macronutrient profile

Ensuring a good balance of macronutrients protein, carbohydrate and fat will help to increase levels of compliance and minimise metabolic adaptation, and multiplying the following figures by your weight in kilograms will provide in grams the minimum quantities of protein, carbohydrate and fat I recommend to create this balance.

  •             Protein: 1g x weight (kg) = minimum grams of protein
  •             Carbohydrate: 1g x weight (kg) = minimum grams of carbohydrate
  •             Fat: 0.5g x weight (kg) = minimum grams of fat

After calculating the minimum quantities of protein, carbohydrate and fat, there will still be some calories left to be consumed to meet the new daily caloric target, despite any deficit. Divide these by three and distribute evenly across protein, carbohydrate and fat.

To calculate how many grams of a particular macronutrient is required, divide the number of calories required accordingly:

  •             Protein: 4
  •             Carbohydrate: 4
  •             Fat: 9

Moulding the system

In a caloric deficit, weight loss efforts will be counteracted by everyday changes in energy levels, hormone concentrations and other metabolic adaptations which is why it is important not to drop caloric intake too dramatically. If you currently eat 1000 or more calories than your body needs for weight maintenance, set your caloric intake at maintenance levels for a few weeks before putting your body into a deficit.

Otherwise begin your programme with a 10 per cent deficit to establish what you can be compliant with, and if a further reduction is realistic, sustainable, or even necessary. Spend a minimum of one week on each level before considering moving on to the next.

You can experiment with the distribution of the additional calories to suit your own needs once the minimum amounts have been met. For example, those with higher activity levels may benefit from an increase in carbohydrate.

After 12 weeks, or on reaching your goal weight, recalculate your BMR and again, multiply this by your activity level to create a new maintenance value. Over a week or two, gradually adjust your current caloric amount to the new maintenance value.

When creating macronutrient profiles, a Personal Trainer should use their own knowledge and experience when recommending foods to meet their clients’ individual needs favoring highly nutritional foods over processed options.

Example: Sophie

Age: 30

Weight: 90kg

Height: 170cm

Activity level: sedentary

Existing average daily caloric intake: kcal 2,500

BMR = (10x90kg)+(6.25x170cm)-(5×30)-161 = kcal 1,652

Maintenance calories: 1.2×1652 = kcal 1,982

Deficit calories (10 per cent): 0.9×1982 = kcal 1,783

Basic macronutrient profile

Protein: 1×90 = 90g (kcal 360)

Carbohydrate: 1×90 = 90g (kcal 360)

Fat: 0.5×90 = 45g (kcal 405)

Total calories: 1,125

Remaining calories: 1783-1125 = kcal 658

Calories to be evenly distributed: 658/3 = kcal 219

Final macronutrient profile

Protein: (360 + 219) = kcal 579 (145g)

Carbohydrate: (360 + 219) = kcal 579 (145g)

Fat: (405 + 219) = kcal 624 (69g)

Total calories: 1,782

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