Nutrition Math 101

Written by Toma Grubb

Sunday, 16 December 2007

TURNING CONCEPTS INTO USEABLE NUTRITION VALUES

or

Nutrition math 101

This is an exercise I think everyone should do to understand the concepts. Once you understand the concepts it is so much easier to use good software to do the daily, weekly and per meal calculations. If you want to do it all manually, this is a tutorial on how to do it.

To be usable, the vague concepts of low fat, low carbohydrate, low cholesterol etc. have to be converted into usable serving sizes of each food.
Before we can do that we need to start with where we are now and where we want to be. The thing we have to start with is what we are trying to accomplish. Is it better blood glucose control? Is it weight control? is it reduction of Cholesterol or some other issues. To be able to make meaningful meal plans we need to first determine is in our goal are we trying to gain weight, loss weight or maintain weight. There are a lot of ideal weight charts all over the internet and in books but that concept is as obsolete as a TR 80, a Sinclair 1000, or an 8 track stereo. They were all state of the art in their day but all have been replaced by more recent developments. The "ideal weight" is now replaced with the "healthy weight

The method of determining a healthy weight suggested by the Center for Disease control is the BMI or body mass index. The BMI is determined by one of several methods. the most accurate are also the most costly. For truly accurate BMI measurement, you need to be weighed with special equipment in water. For most of us this is unnecessary, all we need is the formula method. Body builders, Olympic and professional athletes may find it useful in maximizing there potential , but most of us. it just isn't that critical. This method still isn't perfect, it doesn't take into consideration things like age, muscle density and abnormalities but it is far better than what preceded it. An other deficiency of the BMI method is, two people can have the same BMI, but a different percent body fat. A bodybuilder with a large muscle mass and a low percent body fat may have the same BMI as a person who has more body fat because BMI is calculated using weight and height only. Recently, it has been reported to me by people that I know, that slightly over weight men live longer. ( I have not been able to find confirmation of this report.) If this is true I am sure the "normal' range will be increased. With this said, I believe most of us know where we feel best and are most comfortable. You can have your BMI calculated at Center for Disease Control, Body Mass Index

So you have calculated your BMI and found which weight category your BMI matches. What does this all mean?
BMI is not the only indicator of health risk. BMI is just one of many factors related to developing a chronic disease (such as heart disease, cancer, or diabetes). Other factors that may be important to look at when assessing your risk for chronic disease include: Diet, Physical Activity, Waist Circumference, Blood Pressure, Blood Sugar Level Cholesterol Level, and Family History of disease

All persons who are obese or over weight should try not to gain additional weight. In addition, those who are obese or who are over weight with other risk factors should consider losing weight. A complete health assessment by a physician is the best way to decide the right steps for you. Whatever your BMI, talk to your doctor to see if you are at an increased risk for disease and if you should lose weight. Even a small weight loss (just 10% of your current weight) may help to lower the risk of disease. Physical activity and good nutrition are key factors in leading a healthy lifestyle and reducing risk for disease. Visit our Resource Section for links to information on BMI, obesity, physical activity and nutrition.

If you are unable to use the BMI calculator, or if you are interested in how BMI is calculated, Here are the mathematical formulas. You can calculate BMI using either feet, inches, and pounds, or meters, centimeters, and kilograms.

English Formula

Body Mass Index can be calculated using pounds and inches with this equation

BMI = (

Weight in Pounds
(Height in inches) x (Height in inches)

) x 703

For example, a person who weighs 220 pounds and is 6 feet 3 inches tall has a BMI of 27.5.

( 220 lbs.
(75 inches) x (75 inches) ) x 703 = 27.5

Metric Formula

Body Mass Index can also be calculated using kilograms and meters (or centimeters).

BMI =	Weight in Kilograms (Height in Meters) x (Height in Meters)
	or
BMI = (	Weight in Kilograms (Height in centimeters) x (Height in centimeters)	) x 10,000

For example, a person who weighs 99.79 Kilograms and is 1.905 Meters (190.50 centimeters) tall has a BMI of 27.5.

99.79 Kg
(1.905 m) x (1.905 m) = 27.5

Once we have our present weight and our desired weight we have a starting point for determining how much of each item we should eat each day/meal. Our nutrient intake will be based on how many calories our body needs. This is based on our weight and how active we are.

There are several ways to estimate your calorie needs. You can start with the Quick Estimate. A Quick-Estimate-of-Calorie-Needs is exactly that. It doesn't allow for factors like metabolic rate, age or body fat percentage. So don't use it as an exact calculation of calorie requirements - it's simply a ball-park calorie assessment. If you want a more precise calculation of your daily energy needs, google for the Harris Benedict Formula for Calorie Needs The software we recommend uses this formula and gives you the option of using a general estimate of your activity level or allows you to track fairly precisely.

Quick Estimate of Calorie Needs

If very active	multiply your current weight in pounds	17
If moderately active	multiply your current weight in pounds	15
If typically inactive	multiply your current weight in pounds	13

Example: if you weigh 170 pounds and lead an inactive lifestyle, your calorie needs are very roughly 2200 calories/day. To Lose Weight Deduct 500-1000 Calories. Your calorie-needs are the amount of calories you need to MAINTAIN your weight. To lose weight, you must eat fewer calories than this. For example, 1 pound of body weight is roughly equal to 3500 calories. So if you wish to lose 1 pound of weight per week, you must reduce your calorie needs by 3500 calories a week or 500 calories a day. To lose about 2 pounds a week, reduce your daily calorie-needs intake by 1000 calories.

Note:
(1) Whatever your weight loss requirements, it is best to eat a minimum of 1200 calories (women), or 1600 calories (men).
(2) Don't forget to factor in the calories you burn during exercise.
Fill in the blanks for your calorie needs per day:

      __________pounds (Your current body weight.)
    X__________cal/pound (see the chart above for the cal/pound for your activity level)
     =__________ Your calorie needs per day.
+/-__________ + 500 calories to gain, -500 calories to loose approx 1 pound per week.

Record this number and hold on to it, we will be using it in later. . In Step #4 we will be converting our calorie goal into a PCF goal so we will be able to arrive at the specific grams of Protein, Carbohydrates and Fat we will be including in each meal for the perfect balance that will result in the best health we are capable of. Again it is so much easier to have the software do this for us, but we really need to understand what the software is doing.