A Look into the Science

One diet does not fit all! Has anyone else ever been fixated on that 2000 calorie number? Growing up I remember my mom emphasizing that magical number. But is it really magical? Research says NO!! (see my "A Little Bit of Research" section below to search for articles on this topic) How then did 2000 calories become the standard recommendation and why does it continue to reign? This number fails to accurately take into account important aspects such as height, weight and activity level, however, what it does do is provide a decent estimate to start with.

Counting calories is an important aspect of finding and maintaining your health but it is not the only aspect! What exactly are calories and why should we keep track of them? 

CALORIES or Should I say KILOCALORIES

• First of all when you see "calories" on a label it is really referring to kilocalories- for some reason the government has refused to correct this common error so just be aware that Calories = Kilocalories
• Kilocalories are a measurement of heat energy needed to raise the temperature of 1000 grams of water 1 degree Celsius.
• We are constantly using and consuming kilocalories. This relationship is called energy balance
• To maintain a weight we must find an energy equilibrium(caloric intake =caloric output)
• Positive Energy Balance is when intake exceeds output-->weight gain
• Negative Energy Balance is when output exceeds intake-->weight loss
• Calculate your BMR and Resting Metabolic Rate (RMR):
• The RMR is an estimation of the kilocalories you expend when you are not fasting but completely relaxed- this is typically 6% higher than your Basal Metabolic Rate (calculation of your basic energy requirements when fasting). 
• BMR for Woman= ((weight)/(2.2lb/kg))/(.9kcal/1hr)*24hrs/1Day
• the average number of calories burned per hour in a woman is .9kcal/kg
• Take me for example:
• ((126)/2.2ln/kg))/(.9kcal)*(24hr)= 1,527.3 kcal BMR
• (1,527.3*.06) + (1,527.3)= 1,618.9 kcal RMR
• the average number of calories burned per hour in a man is 1.0kcal/kg
• The BMR and RMR are rough estimates to provide you with a starting point only. Various factors can increase or decrease the actual amount!!!!
• Exercise, Age, Muscle Mass, Body Surface Area and Gender are just a few!
• Physical Activity can increase your energy expenditure as much as 25-40% 
• Energy Expenditure

• Indirect Calorimetry:
• EER: Estimated Energy Requirements that are based on the Food and Nutrition Board (as seen in chart above)
• take into account:
• Weight
• Height
• Gender
• Age
• Physical Activity Level
• See Energy Expenditures from MyPyramid to calculate your estimated expenditure!! (mypyramid.gov)
• This is probably your best estimate as to how many kilocalories you should be consuming within a couple hundred kcals.

Breaking Down your Kilocalorie Consumption into the Food Groups

• Daily Values
• Standards for energy producing nutrients
• Major energy producing nutrients are 
• Fats 20-30%
• Carbohydrates 45-65%
• Proteins 10-35%
• note that you may decide what percentage you choose as long as it equals 100%
• Recommended Range of Kilocalorie allotment

• Translating the Recommended Values to Tangible Numbers:
• EXAMPLE: Expected Energy Expenditure= appx 2400kcal
• Of these 2400 kilocalories
• Fats= (2400* .25)=600kcal/day
• Carbohydrates=(2400*.45)=1080 kcal/day
• Proteins=(2400*.30)=720 kcal/day

****These are the very basics of science in nutrition. Much more goes into finding and maintaining a healthy weight!