Laying the foundation for an effective diet can be a complicated process. Many trainers, in their frustration, turn to computer software programs in an effort to simplify the process. While these programs are indeed handy, a client may lose confidence in an instructor who relies too heavily on software, and too little on their own knowledge. Let's get back to the basics. We will simplify calculating caloric needs and nutrient ratios in this article.

Determining Daily Caloric Requirements

The ISSA's method for determining daily caloric requirements has been around for many years. I am taking the same information here and putting it into a "three step" process. The trainer will need to know the client's sex, percent body fat, weight and average approximate daily activity level to complete the process. You may follow along with the material near the end of Unit 9 in Fitness: The Complete Guide. Remember that Basil Metabolic Rate (BMR) is the number of calories one would expend if they did NO activity all day.

Step 1

For Men: 1 x body weight (kg) x 24 = _ For Women: .9 x body weight (kg) x 24 = _

  • to convert pounds to kg, divide weight in pounds by 2.2

Step 2

In this step you must multiply the result from step 1, by the "multiplier" in the right column that corresponds to the percent body fat range of your client. This step takes into account that pound for pound, leaner people generally have a higher BMR.

  • Men 10 to 14% / Women 14 to 18% = 1.0
  • Men 14 to 20% / Women 18 to 28% = .95
  • Men 20 to 28% / Women 28 to 38%  = .90
  • Men over 28% / Women over 38% = .85 


Male Weight:  200 pounds (90.9 kg)

Body Fat:  15% 

To find weight in kg, divide the body weight in pounds by 2.2. 200 pounds divided by 2.2 = 90.9 kg*

Example Step 1 1 x 90.9 x 24 = 2182 Example Step 2 2182 x .95 (multiplier from table 1 corresponding to 15% body fat) = 2073 BMR = 2073 calories / day

Note: To determine your average BMR per HOUR, simply do not multiply by 24 in the equations in step 1, or divide the daily BMR by 24. In our example, 2073 divided by 24 = 86.4 calories / hour.

Step 3

Now that you know the BMR, the final step in determining daily caloric expenditure is to factor in your daily activity. Obviously, activity means you are going to burn more calories than the BMR. Find where you fall in the activity categories below and multiply your daily BMR (or your hourly BMR if you want to calculate hourly caloric expenditure) by the number on the left of your range to find your daily caloric expenditure.

Average Daily Activity Levels

The Average Couch Potato range:

1.30 (130%) = Very Light: Sitting, studying, talking, little walking or other activities through out the day 1.55 (155%) = Light: Typing, teaching, lab/shop work, some walking throughout the day

The Average Fitness Buff Range:

1.55 (155%) = Light: Typing, teaching, lab/shop work, some walking throughout the day 1.65 (165%) = Moderate: Walking, jogging, gardening type job with activities such as cycling, tennis, dancing, skiing or weight training 1-2 hours per day

The Average Athlete or Hard Daily Training Range:

1.80 (180%) = Heavy: Heavy manual labor such as digging, tree felling, climbing, with activities such as football, soccer or body building 2-4 hours per day 2.00 (200%) = Very Heavy: A combination of moderate and heavy activity 8 or more hours per day, plus 2-4 hours of intense training per day


Using the same 200 pound male with a daily BMR of 2073 calories per day, we determine that he is mostly sedentary during the day with the exception of some jogging and about 40 minutes of weight training. This would put him in the activity category of 1.65, or 165% of his BMR.

Total daily caloric expenditure = 2073 calories x 1.65 = 3420 calories

Our 200-pound male at 15% body fat and a BMR of 2073 calories per day uses a total of 3420 calories on an average day. When planning a zig-zag diet program for this client, this would be your starting daily caloric mark, and you would zig-zag up and down from this number.

Remember that there are 2500 calories in a pound of muscle and 3500 calories in a pound of fat. For a client to gain one pound of muscle per week, you need to make sure that every seven days they have consumed 2500 calories (average of 350 calories per day) more than they expended. For a client to lose one pound of fat per week, make sure that every seven days, the client has consumed 3500 fewer calories (average of 500 calories per day) than they expended for the week.

Determining Proper Ratios of Protein, Fat and Carbohydrates

Now that we know how many total calories need to be consumed each day, where do the calories come from? In the diet there are three worthwhile sources of calories: fat, protein and carbohydrates. There are many different ratios, and methods of determining those ratios, in use today. Following is just one of the many ways to figure the caloric ratio, but seems to work pretty well, with a good success rate.

Calories per gram of the three major nutrients: 

Protein  4 calories per gram  

Carbohydrates 4 calories per gram

Fat 9 calories per gram 

We will begin with protein requirements. It is now fairly common knowledge that active people need more protein than the RDA, but just how much is needed? Take a look at the following chart to determine how much protein is required for different categories of people.

Protein Requirements in Grams per Pound of Body Weight per Day

  • Sedentary Adult (RDA) 0.40
  • Adult Recreational Exerciser 0.75
  • Adult Competitive Athlete 0.90
  • Adult Building Muscle Mass 0.90
  • Dieting Athlete 1.00
  • Growing Teenage Athlete 1.00

Let's continue with our sample athlete from the Determining Daily Caloric Needs section. Let's say our 200-pound male is an adult competitive athlete. He will need .90 grams of protein per pound of body weight per day. Then, from the table above we know there are 4 calories per gram of protein, so we multiply the grams of protein per day by 4 to get calories from protein.


.90 x 200 = 180 grams of protein per day 180 grams x 4 calories per gram = 720 calories from protein

Fat - Learn More

Percentage of calories from fat can vary quite a bit, depending on whom you talk to. The RDA, for example, says that fat calories should consist of no more than 30% of the diet. This number is good for general health, but is considered too much fat for individuals seeking peak performance and physical condition. The ISSA recommends that fat calories stay at around 15% of total calories.

Please keep in mind that many people, especially in the US, are accustomed to very high fat diets. Often time clients may come to you with a diet closer to 50% of calories from fat! In these cases, you may need to wean them off of the fat slowly, or they are likely to lose interest in the fitness lifestyle. It would be best to start clients like this at a percent of fat you feel they can tolerate (30 to 35% of calories from fat, for example), and then slowly continue to reduce the amount over time.


Continuing with our 200-pound male athlete:

.15 (15%) x 3420 total daily calories = 513 daily fat calories 513 fat calories / 9 calories per gram of fat (see table 2) = 57 fat grams per day

Carbohydrates - Learn More

Now that we have determined calories from protein and fat, the remainder of the calories can only come from one source: CARBS! Carbohydrates are the body's preferred source of calories, and should make up the largest calorie supply of any nutrient in the diet. We determine the calories needed from carbohydrates by simply subtracting the calories from fat and protein from the total daily calories.


Continuing with our 200-pound male athlete:

3420 daily cals - 513 fat cals - 720 protein cals = 2187 carbohydrate calories 2187 carbohydrate calories / 4 calories per gram (see table 2) = 547 grams of carbohydrates per day

Our 200-pound adult male athlete is eating a caloric ratio of:

  • Fat 15%
  • Protein
  • 21%
  • Carbohydrates  64% 


There are many different ways to determine daily caloric needs and nutrient ratios. What I have done here is taken the ISSA principles, and introduced the method of putting it all together that I have used with our students for the past year. The students really seem to like this method, so I wanted to make it available to all who care to use it. The ratios can be tweaked a little bit, but I find this method produces excellent ratios for almost all types of clients. If you have questions, please contact me at, or call our tech support line at 800 892-4772.

About the Author



ISSA was the first organization to recognize the need for specialized levels of education in the fitness field.

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