Almost every report you hear about obesity and health also talks about BMI. Just what is BMI and why does it matter?

What is BMI?

BMI stands for Body Mass Index and it is recognized by the National Institutes of Health and The World Health Organization as the best standard to judge obesity. Not everyone agrees with this judgment, and we’ll talk about that disagreement later.

BMI is a quick and easy calculation to estimate how much fat you have. Mathematically, which you shouldn’t worry too much about, BMI is defined as your body weight divided by the square of your height.

The idea is, the higher your BMI the more fat you probably have. And the more fat you have the less physically active you probably are. And the less physically active you are and the more fat you have then the less chance you have of being healthy.

BMI is popular because it easy to calculate. All you need to know is your height and weight, which are both easy to measure. And that’s the source of the problem with BMI too. We all know people can be the same weight and height and look totally different. One person can be mostly flab and another person can be solid muscle, and they’ll have the same BMI.

Researchers looked at how various BMI ranges were related to disease and death. They found certain BMI ranges were associated with better health, and certain BMI ranges were associated with worse health. They assigned weight ranges into categories based on projected health risk.

Here are the BMI categories the researchers came up with:

·        Underweight: less than 18.5.

·        Ideal: greater than or equal to 18.5 but less than 25.

·        Overweight: greater than or equal to 25 but less than 30. This is approximately 10 percent over your ideal body weight.

·        Obese: greater than or equal to 30 but less than 40. This is approximately 30 pounds over your ideal weight.

·        Morbidly Obese: greater than or equal to 40. This is approximately 100 pounds over your ideal weight.

These relationships were figured out by statistics, which means they were calculated using data from lots of people. It doesn’t say anything about how you in particular will turn out health-wise. But statistically, to be in the healthiest group, you should have a BMI in the ideal range, between 18.5 and 25.

To help you get a feel for how height, weight, and BMI are related, here are the BMI ranges for someone who is 5’ 9" tall:

What are the Historical Obesity Rates?

In the USA, the percent of obese adults varied little from 1960 to 1980. Obesity increased considerably between 1980 and 1991, from 13 to 21 percent among men and from 17 to 26 percent among women. This trend continued. In 1999–2000 obesity increased to 28 percent of men and 34 percent of women.

Imagine a movie of how obesity rates have changed over time on a state by state basis. According to the Centers for Disease Control (CDC) statistics, in 1990 only 4 states had obesity rates between 15-19 percent and no states had rates above 20 percent.

Move the calendar ahead 10 years to 2000 and a lot had changed. All 50 states had obesity rates of 15 percent or more. Thirty-five states had obesity rates as high as 20 percent or greater.

Flip the calendar ahead another 5 years to 2005. Only 4 states had obesity rates less than 20 percent and 17 states had obesity rates of 25 percent or greater. Three states—Louisiana, Mississippi, West Virginia—had obesity rates greater than 30 percent.

This isn’t just an American problem. Worldwide obesity rates are climbing fast too.

What are the Current Obesity Rates?

Here are the general obesity rates in the US as of 2002-2004:

·        Over 66 percent of adults are overweight or obese.

·        Over half of the adults are overweight.

·        Nearly one-third of adults are obese.

·        17 percent of adolescents ages 12-19 years old are overweight.

·        19 percent of children ages 6-11 years old are overweight.

·        Nearly 3 percent of men are extremely obese (having a BMI of 40 or more)

·        Nearly 7 percent of women are extremely obese.

Obesity varies a lot by race/ethnicity and by age as of 2002-2004:

·        About 30 percent of non-Hispanic white adults are obese.

·        About 45 percent of non-Hispanic black adults are obese.

·        Nearly 37 percent of Mexican Americans are obese.

·        Nearly 29 percent of adults between 20 to 39 years old are obese.

·        Nearly 37 percent of adults between 40 to 59 years old are obese.

·        31 percent of adults 60 years or older are obese.

A RAND study found the percentage of Americans who are extremely obese¾about 100 pounds or more overweight¾increased by 50 percent from 2000 to 2005. That’s twice as fast as the growth of moderate obesity.

US obesity rates may be even worse than they appear. These numbers are gathered via a telephone survey in which people volunteer their own height and weight numbers. It has been found that people aren’t completely honest about their height and weight, which could lead to a significant under-reporting of obesity rates.

According to the World Health Organization, worldwide there are:

·        Over 300 million obese adults.

·        Over one billion overweight people.

·        Over 830 million undernourished people.

What we see now, probably for the first time ever, is that more people are overweight than there are hungry. Most of the hungry live in the underdeveloped countries. Only an average of 300 calories a day stands between getting enough calories and hunger.

What are the Future Obesity Rates?

As you can probably imagine, the future looks grim.

·        The International Obesity Task Force (IOTF) estimates that nearly 287 million children worldwide could be overweight or obese by 2010, which is 85% more than a decade earlier.

·        The overall obese population could possibly rise to more than 700 million by 2015, with nearly 2.3 billion overweight globally.

·        In the USA and Canada, it’s thought that half of all adults are likely to be obese with only one in five people of healthy weight.

·        One in three people born in the USA today is expected to develop Type II diabetes. The rest of the world isn’t far behind.

There’s no sugar coating these numbers. They are what they are. I don’t expect scary numbers to make a difference to people, but they are an interesting perspective on where the world is headed. We are going to have an avalanche of health problems coming down on us in the not so distant future.

What Does this Mean in Real Pounds?

The BMI measurement can be a little abstract. What does a BMI of 27.5 look like? What does a high rate of morbid obesity really mean? It’s hard to tell because they don’t give out actual weight numbers in the statistical data. I was able to dig up some weight numbers that can help visualize increasing obesity rates.

In the 1960s and 1970s, average-weight of American adults increased only a pound or two in each decade. Then in 1980, the average adult America gained 8 pounds. And in 2002, the average American weighed nearly 25 pounds more than they did in 1960, yet averaged only an inch taller.

Averages are still hard to visualize. In 2004, the International Health, Racquet & Sportsclub Association sponsored a nationwide survey to see what people actually weighed. Here’s what they found:

·        3.8 million Americans weigh more than 300 pounds, which is fine if you are 7 foot tall, but it’s not so fine if you are of average height.

·        More than 400,000 Americans weigh more than 400 pounds.

·        1 in 9 adult men weighs more than 250 pounds.

·        1 in 6 women weighs more than 200 pounds.

·        The average adult male weighs 196 pounds.

·        The average woman weighs 163 pounds.

I don’t know if these numbers seem high or low to you, but using real weights instead of BMI numbers makes it easier to see what’s going on.

Why Should You Care About Your BMI?

You should care about BMI for two reasons:

1.      A lot of medical conditions are related to your weight. Knowing your own BMI gives you an idea of your health risks.

2.      BMI is frequently mentioned in studies and news reports. Knowing your BMI will help you make sense of new information as it comes in.

Being overweight may increase your risk of the following health problems:

·        Hypertension

·        Dyslipidemia (for example, high LDL cholesterol, low HDL cholesterol, or high levels of triglycerides)

·        Type II diabetes

·        Coronary heart disease

·        Stroke

·        Gallbladder disease

·        Osteoarthritis

·        Sleep apnea and respiratory problems

·        Some cancers (endometrial, breast, prostate, and colon)

·        “Man boobs,” or pseudo gynecomastia

·        Psychological problems (low self-esteem, depression)

·        Infertility

·        Knee joint, and other musculo-skeletal problems

·        Skin problems

This time it’s not just personal. People with a BMI over 40 are expected to have twice the health costs of normally weighted people. Moderately obese people (a BMI of 30-35) are expected to have increased health care costs of 25 percent. Obesity is a problem that affects us all in one way or another.

Calculating Your BMI

There is a table you can use to look up your BMI on the following page.

 The BMI calculation for children is more complicated because they are still growing. Please go to http://YourDesignerDiet.com to calculate the BMI for children (and adults too).

What is your BMI? Look in the table above’. If you are overweight or above, take a look at section Why Should You Care About Your BMI? to see what problems you may have as a result.

What do you think about your BMI? Does it seem accurate to you? It may not be.

		Ideal						Overweight						Obese
BMI		19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40
	Weight (Pounds)
Height (Inches)	58	91	96	100	105	110	115	119	124	129	134	138	143	148	153	158	162	167	172	177	181	186	191
	59	94	99	104	109	114	119	124	128	133	138	143	148	153	158	163	168	173	178	183	188	193	198
	60	97	102	107	112	118	123	128	133	138	143	148	153	158	163	168	174	179	184	189	194	199	204
	61	100	106	111	116	122	127	132	137	143	148	153	158	164	169	174	180	185	190	195	201	206	211
	62	104	109	115	120	126	131	136	142	147	153	158	164	169	175	180	186	191	196	202	207	213	218
	63	107	113	118	124	130	135	141	146	152	158	163	169	175	180	186	191	197	203	208	214	220	225
	64	110	116	122	128	134	140	145	151	157	163	169	174	180	186	192	197	204	209	215	221	227	232
	65	114	120	126	132	138	144	150	156	162	168	174	180	186	192	198	204	210	216	222	228	234	240
	66	118	124	130	136	142	148	155	161	167	173	179	186	192	198	204	210	216	223	229	235	241	247
	67	121	127	134	140	146	153	159	166	172	178	185	191	198	204	211	217	223	230	236	242	249	255
	68	125	131	138	144	151	158	164	171	177	184	190	197	204	210	216	223	230	236	243	249	256	262
	69	128	135	142	149	155	162	169	176	182	189	196	203	210	216	223	230	236	243	250	257	263	270
	70	132	139	146	153	160	167	174	181	188	195	202	209	216	222	229	236	243	250	257	264	271	278
	71	136	143	150	157	165	172	179	186	193	200	208	215	222	229	236	243	250	257	265	272	279	286
	72	140	147	154	162	169	177	184	191	199	206	213	221	228	235	242	250	258	265	272	279	287	294
	73	144	151	159	166	174	182	189	197	204	212	219	227	235	242	250	257	265	272	280	288	295	302
	74	148	155	163	171	179	186	194	202	210	218	225	233	241	249	256	264	272	280	287	295	303	311
	75	152	160	168	176	184	192	200	208	216	224	232	240	248	256	264	272	279	287	295	303	311	319
	76	156	164	172	180	189	197	205	213	221	230	238	246	254	263	271	279	287	295	304	312	320	328