Body Mass Index (BMI) BMI is a measurement of body fat based on height and weight that applies to both men and women between the ages of 18 and 65 years. The simple tools below will calculate your BMI (using either U.S. or metric units) and tell you your "weight status" according to standards published by American Journal of Clinical Nutrition.

BMI Calculator (U.S. Units) Weight: *(lbs) *Height: *(ft)* *(in) Your BMI:

BMI Calculator (Metric Units) Weight: *(kgs) Height: *(cm) Your BMI:

What Does BMI Value Mean? Under weight = 18.5 or less Normal weight = 18.5 to 24.9 Over weight = 25 to 29.9 Obese = 30 to 39.9 Extremely Obese = 40 or more

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Note, that this is only one of many ways to assess your weight. If you have any concerns about your weight, please discuss them with your physician, who can address your specific situation.

When Does Weight Change Occur? We lose weight when the energy we expend in daily living is greater than the energy we get from the food we eat. When this deficit condition (energy imbalance) exists, our body gets the extra energy it needs by "burning" body weight - mainly fat - and using the energy stored in the fat. The result of this process is we lose weight as our body burns the fat it needs to return to an energy balance, or equilibrium. Weight gain can be explained by applying the converse of this reasoning. Because body weight is only lost or gained when there is an energy imbalance, we do not experience a weight change when the energy value of the food we consume equals the amount of energy we expend in day-to-day living. This point of energy balance represents the amount of energy required to maintain our body weight. Since the calorie is the measure of energy, this balance point is often referred to as the Weight Maintenance Calorie level.

Weight Loss Math

People on any weight-loss diet invariably want to know how much weight they will lose - and how fast. Simple metabolic calculations make a rough estimate possible.

Physiologists 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.

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. Note that only the Weight Loss Prediction tables in Total Fitness account for this phenomenon.

Your Daily Calorie 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 (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 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 Needs:

Again note that these values are approximate. For a more accurate indication of your daily calorie needs see any of the Weight Maintenance eBooks which contain comprehensive Weight Maintenance Calorie 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.)

Anyone Can Become Overweight A study by R.S. Vasan, M.D. (of The Framingham Heart Study) and other United States and United Kingdom researchers was published in a 2005 issue of the Annals of Internal Medicine. This study followed 4,000 people for three decades and suggests that in the long term, 90 percent of men and 70 percent of women will become overweight (with a BMI ³ 25). Interestingly, half of the men and women in the study who had made it well into adulthood without a weight problem ultimately also became overweight and a third became obese (with a BMI ³ 30). The message is that you can never become complacent. You must continually watch your weight because everyone is at risk of becoming overweight. Click here to read the entire article.

Valuable Resource Links The Weight-Control Information Network provides the general public, health professionals, the media, and Congress with up-to-date, science-based information on weight control, obesity, physical activity, and related nutritional issues. The Healthy Weight Forum is a peer education based forum offering support, motivation, recipes and fellowship for those interested in reaching and maintaining a healthy weight. The American Obesity Association is the only obesity organization focused on changing public policy and perceptions about obesity. News, articles, providers and advocacy. The American Heart Association Informing the public about misleading weight-loss claims and fad diets that can undermine good health. Better lifestyle habits help reduce your risk for heart attack. Harvard School of Public Health/Healthy Weight provide timely information on diet and nutrition for clinicians, allied health professionals, and the public. We Can! (Ways to Enhance Children's Activity & Nutrition) is a national education program designed for parents and caregivers to help children 8-13 years old stay at a healthy weight. Weight Loss Information The goal is to provide weight loss information, as well as tips and services on issues such as dieting, nutrition, exercise, so that you can better achieve your health and fitness goals.