How much should I eat?

Posted: December 12, 2010 in Nutrition

Nutrition (also called nourishment or aliment) is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. You may ask, how is nutrition related to my fitness goal?  Nutrition actually plays a bigger part than the training itself.

First, we’ll be talking about energy balancing. This will take into consideration the calories consumed and the calories expended.


Neutral energy balance is when the calories you take in is equal to the calories expended. This will result in maintenance of weight

Negative positive balance is when the calories you take in is less than the calories expended. This will result in lower weight and fat loss.

Positive energy balance is when the calories you take in is greater than the calories expended. This will result in increased weight with higher fats and muscle mass.

It’s easy to calculate the amount of calories we consume a day by reading the nutritional information on food labels. But how about caloric expenditure? We need to know how many calories are used up by our bodies in order to ensure that we have the desired energy balance to achieve our fitness goals.

Daily energy expenditure consists of three components: basal metabolic rate (BMR), diet-induced thermogenesis (DIT) and your physical activity level.


Basal metabolism rate is the amount of calories you need to maintain the body during resting conditions. It varies from people to people based on their age, gender, height, weight and body composition (muscle mass).

Physical activity level is the amount of physical activity you get daily. Physical activity is any movement that requires your muscles and that can expend calories. The higher your physical activity level, the more calories you burn.

Diet-induced thermogenesis, or thermic effect of food is the energy expended by our bodies in order to consume and process food. So now you know eating can help you burn calories too!


Your basal matabolism rate (BMR) can be estimated by the Schofield Equation (1985)











However, that’s just the BMR and not the total number of calories you would need a day if you take into consideration the amount of physical activity. With more physical activity, you would naturally need more energy.

Multiply your BMR by the Physical Activity Level Factor and you would get the Estimated Energy Requirements (EER) you would need daily.









For example, if a female is 20 years old weighing 70kg and has a physical activity level factor of 1.5, her total daily caloric requirements would be (14.8 x 55kg + 487) x 1.5 = 1951.5kcal. In order to achieve the desired enerygy balance to achieve your fitness goals, consume calories according to your caloric requirements.


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