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  • Based on BMI, about one-third of Americans are considered obese, but new research shows that when other methods of measuring obesity, such as body fat percentage, are factored in, that number may be closer to 60 percent
  • Body-mass index (BMI), which gauges weight in relation to height, is widely used as a measure of overweight and obesity, but it is a flawed measurement tool, as it tells you nothing about where fat is located in the body, and does not measure body fat
  • Levels of the hormone leptin are also strongly associated with body fat percentage; testing your leptin levels could be used in addition to your BMI to help get a more accurate picture of your true risk of obesity and related diseases
  • Measuring your waist circumference and your body fat percentage are two tools that may be superior to BMI for measuring your risk of obesity-related diseases, and are powerful indicators of your health
 

New Study Shows Obesity Rate Is Actually Far Worse than Previously Recognized

April 21, 2012 | 33,574 views
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By Dr. Mercola

In the United States, where two-thirds of all states already have obesity rates exceeding 25 percent, and 12 states now have obesity rates over 30 percent, it is shocking to hear that these rates may actually be underestimated.

But this is precisely what new research has revealed.14

Body-mass index (BMI), which gauges weight in relation to height and is widely used as a measure of overweight and obesity, is to blame for the flawed assessments.

Are Nearly 60% of Americans Obese?

Researchers compared BMI measurements to body fat percentage (using a DEXA scan, which is a FAR more accurate method to assess body fat percentage) among 1,400 people.

For women, about half of those who were not classified as obese according to BMI were considered obese according to body fat.

Among men, one-quarter of those not identified as obese by BMI were found to be obese by body-fat measures.

In all, nearly 40 percent of participants whose BMI classified them as overweight were actually obese when their percentage of body fat was taken into account.

According to lead author Dr. Eric Braverman, president of the nonprofit Path Foundation in New York City, "Based on BMI, about one-third of Americans are considered obese, but when other methods of measuring obesity are used, that number may be closer to 60%."i

As such, BMI also neglects to factor in how muscular you might be.

Athletes and completely out-of-shape people can have similar BMI scores, or a very muscular person could be classified as "obese" using BMI, when in reality it is mostly lean muscle accounting for their higher-than-average weight.

Dr. Braverman says of BMI:ii

"Some people call it the 'baloney mass index."

Many studies, such as one published in the Journal of the American College of Cardiology,iii have found that a high BMI was associated with a lower risk of death, a phenomenon known as the "obesity paradox." This finding as an example of how BMI is a flawed measurement tool, as it tells you nothing about where fat is located in the body, and it appears that the location of the fat is more important than the amount of fat when it comes to measuring certain health risks, such as heart disease risks. BMI also uses weight as a measure of risk, when it is actually a high percentage of body fat that makes a person obese.

Could Testing Your Leptin Levels Make Your BMI More Useful?

The researchers found that levels of the hormone leptin were strongly associated with body fat percentage, and suggested that testing your leptin levels could therefore be used in addition to your BMI to help get a more accurate picture of your true risk of obesity and related diseases.

The hormones your fat cells produce impact how much you eat and how much fat you burn. One of these hormones is leptin, and leptin sends signals that reduce hunger, increase fat burning and reduce fat storage. That is, if your cells are communicating properly and can "hear" this message.

If you are eating a diet that is high in sugar, fructose and grains, as the sugar gets metabolized in fat cells, fat releases surges in leptin. Over time, if your body is exposed to too much leptin, it will become resistant to the leptin (just as your body can become resistant to insulin). Leptin resistance causes an increase in the visceral fat your body produces. Likewise, it is through an inflammatory process that it's thought visceral fat causes its damage, and the same diet that makes you leptin resistant will also increase inflammation and body fat in your body. By tending to one factor -- diet -- you can reduce your risk of both becoming leptin resistant and producing excess visceral fat.

What's a Better Way to Gauge Your Weight Health than BMI?

Another simple and inexpensive option is measuring your waist circumference, as a thick waist is a well-known sign of a build-up of visceral fat, a dangerous type of fat around your internal organs that is strongly linked with type 2 diabetes, heart disease and nonalcoholic fatty liver disease.

It is thought that visceral fat is related to the release of proteins and hormones that can cause inflammation, which in turn can damage arteries and enter your liver, affecting how your body breaks down sugars and fats. When your body routinely stores excess visceral fat, you increase your risk for high blood pressure, high cholesterol, vascular disease, atherosclerosis (hardening of your arteries) and an increased thickness in the walls of your heart.

Your waist size is also a powerful indicator of insulin sensitivity, as studies clearly show that measuring your waist size is one of the most powerful ways to predict your risk for diabetes. Determining your waist size is easy. With a tape measure, figure the distance around the smallest area of your abdomen below your rib cage and above your belly button. If you're not sure if you have a healthy waist circumference, a general guide is:

  • For men, between 37 and 40 inches is overweight and more than 40 inches is obese
  • For women, 31.5-34.6 inches is overweight and more than 34.6 inches is obese

The other tool, which many experts are now leaning toward as the most accurate measure of obesity, is body fat percentage. As it sounds, this is simply the percentage of fat your body contains, and it can be a powerful indicator of your health. Too much body fat is linked to chronic health problems like high blood pressure, high cholesterol, heart disease, diabetes, and cancer. Too little body fat is also problematic and can cause your body to enter a catabolic state, where muscle protein is used as fuel. A general guideline from the American Council on Exercise is as follows:iv

Classification Women (% fat) Men (% fat)
Essential Fat 10-13% 2-5%
Athletes 14-20% 6-13%
Fitness 21-24% 14-17%
Acceptable 25-31% 18-24%
Obese 32% and higher 25% and higher

How to Measure Your Body Fat

Body fat calipers are one of the most trusted and most accurate ways to measure body fat. A body fat, or skinfold, caliper is a lightweight, hand-held device that quickly and easily measures the thickness of a fold of your skin with its underlying layer of fat. Taken at three very specific locations on your body, these readings can help you estimate the total percent of body fat within your entire body.

You can also use a digital scale that determines body fat, which is what I use personally. I use an Eat Smart Precision GetFit Body Fat Scale that I picked up from Amazon for around $50. Currently my body fat measures at 13.5 percent on this scale, although I think it is actually closer to 11 percent or 12 percent. Although many body fat measurements can be inaccurate, they are nearly all more accurate than BMI, and are particularly useful to determine whether you are gaining or losing fat. Although the absolute value may be off, the direction you are going (whether your body fat is going up or down) will be very accurate, and this is an incredibly useful measure of whether you're nearing your health goals or not.

As I mentioned earlier, a DEXA scan is probably one of the most accurate ways to measure body fat but it is not at all easy to find a center that uses them to measure body fat percentage. There are many DEXA scans out there but most are used to measure bone density. Additionally, a DEXA scan is an X-ray, which will expose you to radiation, and is far more expensive than all of the other methods discussed. For a fraction of the price of one DEXA scan you can pick up an Eat Smart scale and merely step on it each day to monitor your progress. 

Remember that it is FAR better to monitor your body fat percentage than it is your total weight, as the body fat percentage is what dictates metabolic health or dysfunction -- not your total weight.

Tried-and-True Tips for Reaching a Healthy Weight

Once you review the research, it's clear that if you are serious about losing weight, you have got to strictly limit the amount of fructose in your diet, as evidence is mounting that excess sugar, and fructose in particular, is the primary factor in the obesity epidemic. So cutting soda from your diet is essential. However many fail to appreciate the importance of cutting out other sources of fructose, including those found in processed foods, fruit juice, excessive fruit and so-called "healthy" sweeteners like agave.

Ideally you should keep your total fructose consumption below 25 grams per day and this includes fruits. This is especially true if you have insulin resistance and are overweight, have high blood pressure, diabetes or high cholesterol.

For the majority of people, severely restricting carbohydrates such as sugars, fructose, and grains in your diet will be the key to weight loss. Refined carbohydrates like breakfast cereals, bagels, waffles, pretzels, and most other processed foods quickly break down to sugar, increase your insulin levels, and cause insulin resistance, which is the number one underlying factor of nearly every chronic disease and condition known to man, including weight gain.

As you cut these dietary villains from your meals, you need to replace them with healthy substitutes like vegetables and healthy fats (including natural saturated fats!). Your body prefers the carbohydrates in vegetables rather than grains and sugars because it slows the conversion to simple sugars like glucose, and decreases your insulin level. When you cut grains and sugar from your meals, you typically will need to radically increase the amount of vegetables you eat, as well as make sure you are also consuming protein and healthy fats regularly.

I've detailed a step-by-step guide to this type of healthy eating program in my comprehensive nutrition plan, and I urge you to consult this guide if you are trying to lose weight.

The foods you choose to eat will be the driving force behind successfully achieving your weight loss goals -- even more so than exercise. But exercise is still important for weight loss and optimal health. The key to boosting weight loss and getting the most out of your exercise routine is to make sure to incorporate high-intensity, short-burst-type exercises, such as my Peak Fitness Program, two to three times per week. Several studies have confirmed that exercising in shorter bursts with rest periods in between burns more fat than exercising continuously for an entire session.

If you are struggling with your weight, exercise is clearly one of the key factors that can synergize the effects of healthy food choices and help you reach your short- and long-term weight loss goals.

References:


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