Weight Loss Math

Weight control researchers have long known that to lose one pound of body weight requires that we eat 3500 Calories less than we burn, creating what's called a calorie deficit. Thus, if a person's total calorie deficit over time is known, their weight loss over time can be calculated. For example, assume a man expends about 2500 Calories in day-to-day living. (In other words, if this man eats about 2500 Calories per day he will neither gain nor lose weight.) If he goes on a 1500 Calorie per day reducing diet, his daily deficit would be 2500 - 1500 = 1000 Calories. In one week his deficit would be 1000 Calories per day x 7 days = 7000 Calories, and he should lose 7000/3500, or two pounds. (Note that the same math and logic can be used when weight is expressed in kg. In this case it takes a kcal deficit of 7700 kcal to lose one kilo of body weight.)

This computation technique, however useful, is somewhat crude. Primarily because the preceding calculation does not account for a very important scientific fact: As we lose weight we actually need fewer calories to maintain our lower weight. As a result, if a dieter's calorie intake remains constant over some period of time, their calorie deficit will decrease during their diet and the rate at which they lose weight will also decrease with time. And this effect becomes increasingly important with longer duration diets and when more weight is lost.

Only the Weight Loss Prediction tables in Weight Control and Total Fitness, (both available in U.S., metric and U.K. ediditions and published by NoPaperPress.com) account for this phenomenon. The following Weight Loss Prediction table is one of many found in Weight Control - U.S. Edition.

(Note that the numbers in the highlighted box in the table below are the time in days for a 160 lb woman to lose 20 lbs depending on the number of calories she eats.)

Your Daily Calorie (kcal) Needs

Your daily calorie needs (also called Weight Maintenance Calorie level) in simplified terms is the sum of your basal metabolic energy (also referred to as basal metabolic rate or BMR) and your Activity Energy.

Basal Metabolic Rate (BMR)

Your BMR refers to the energy your body expends performing involuntary functions such as cirulating blood, breathing, glandular activity, contraction of the intestines, etc. All these processes require energy. Test data show that the BMR depends on gender, age, height and weight.

Activity Energy & Activity Levels

Your activiy level depends on how physically active you are. This leads to the amount of energy you expend over and above your basal energy.

Use the following calculators to determine your BMR, estimate your Activity Level and then find your Total Daily Calorie (kcal) Needs, that is your Weight Maintenance Needs.

BMR Calculator U.S. or Metric units (click one) U.S. Metric (click one) Female Male : Height (in or cm) : Weight (lbs or kgs) : Age (years) BMR:

Does your BMR change? As we grow older, our BMR steadily decreases. In youth, BMR is higher, and as we age we have less lean body mass - slowing the BMR. The more lean tissue on the body, the higher the BMR, the more fatty body tissue, the lower the BMR. The good news is that an individual can raise their basal metabolic rate by undertaking regular strength and cardio exercise! This calculator should be used only as a general guideline. The numbers are approximations, and the calories you need may be slightly more or slightly less.

Activity Level & Daily Calorie (kcal) Needs Enter BMR (from BMR Calculator above): Sedentary (little or no exercise) Lightly active (light exercise/sports 1-3 days/wk) Moderately active (moderate exercise 3-5 days/wk) Very active hard exercise/sports 6-7 days a wk) Extra active hard exercise/sports & physical job) Daily Calorie (kcal) Needs:

Again note that these values are approximations. For a more accurate indication of your daily calorie needs see either Weight Control or Total Fitness, eBooks by NoPaperPress that contain comprehensive Weight Maintenance Calorie (kcal) tables. (Presenting the data in tables allows you to see at a glance the affect of gender, age, activity level and particularly body weight on your weight maintenance calorie needs.)