Monday, April 29, 2013

Engineering the Perfect Body, Part 2: Waist Measurements



In my previous post, I tried to convince you that if you want to have good health and fitness today, as well as in your 80s and 90s, then you should immediately start building your Spartan body. I also argued that if you eat a good diet and exercise, building and maintaining this new body would be pretty easy. But how do you know that all of your changes are working?

Without blood tests, you can't see many of the indicators of poor health (e.g., blood cholesterol, glucose, and cortisol tests). However, there are visual indicators that represent your body's overall degree of dysfunction. The most reliable (and obvious) is a growing waistline and how that waistline relates to your height and hips.

Why is Abdominal Obesity so Bad?
In my Stress and Metabolic Syndrome X post, I talked about how all the risk factors associated with Metabolic Syndrome X (e.g., high blood pressure, incorrect blood lipids, insulin resistance, large abdominal circumference) are associated with chronically excessive blood cortisol levels. One of the many consequences of excess cortisol levels is increased abdominal fat.

Abdominal fat is primarily composed of visceral fat cells and is used as emergency (or short-term) fat storage and to warm and secure major organs. Because of this, there shouldn't be much energy stored in visceral fat (it comprises about 3% of a person's total body weight). (1) This healthy condition is seen as a flat waistline.

Subcutaneous fat is used for long-term energy storage. Visceral fat is used for short-term energy storage. When visceral fat is used for long-term storage, then a person's waistline will increase. If a person has a conspicuously large belly (e.g., pot belly, beer belly) then they are likely suffering from chronic excess cortisol levels and high consumption of refined carbohydrates.

But, when a person experiences chronically elevated cortisol levels, they become insulin resistant (because cortisol counter-regulates insulin). Insulin is a storage hormone that directs sugar and fat in the blood into long-term and short-term energy storage cells (e.g., fat, liver, and muscle cells). When a person becomes insulin resistant, excess blood sugar and fat gets funneled into visceral fat cells, which increases the size of their waist. (2)

If this dysfunctional situation is not quickly corrected, then your waist will continue to grow with time as more and more blood sugar and fat are forced into visceral fat cells. If this situation is allowed to continue for decades, then your likelihood of developing heart disease, stroke, and diabetes increases.

Understanding the relationship between an expanding waistline, cortisol, and poor health means that your waist measurement becomes a general barometer for your overall health. In very simplistic terms, if your waistline is expanding, then your overall health is getting worse; if your waistline is shrinking (or is within a healthy range), then your overall health is getting better.

(Before I move on I should point out that being thin doesn't necessarily make you immune from developing heart disease or diabetes. Excess cortisol is just one of the many different ways to create dysfunction in the human body. However, because I believe that chronic elevation of cortisol is a major reason that a person would develop heart disease, stroke, and diabetes, then I am arguing that a shrinking waistline will considerably lower your odds of developing these diseases because it shows that cortisol levels are dropping.)

Waist Circumference
The first step in assessing your level of health is to measure your waist circumference. In general, a person's risk of developing heart disease (and high blood pressure, Type 2 diabetes, and stroke) increases when: (3)
  • A male's waist circumference goes above 40 inches.
  • A female's waist circumference goes above 35 inches.

To determine the girth of your waist, measure the circumference of your waist across (or just above) the belly button (see illustration below).


There is one big problem with the waist measurement: No scale.

For example, just looking at the criterion above, you'd think that a male with a waist measurement of 39 inches is not yet in danger, but this is not necessarily true. Without knowing what your waist-size is supposed to be, then you might not become concerned about your health until a fair amount of damage has already been done to your body. You can solve that by using the waist-to-height and waist-to-hip ratios.

Waist-to-Height Ratio (WHtR)
As I said in the previous section, the waist measurement doesn't tell you if your waist is starting to get too big or not, only that you are in trouble if you are a man with a waist larger than 40 inches or a woman with a waist larger than 35 inches. But what if you are a man with a waist measurement of 36 inches? Is that good or bad? It all depends on your height.

Relating your waist to your height allows you to establish a healthy range for the waist measurement, which helps you better use your waist measurement to troubleshoot your health. For example, the hypothetical male with the 36 inch waist would likely be fine if his height were above 71 inches. However, if he were 70 inches or shorter, then he should become concerned (see table below).

Click here for larger image.

This is where the WHtR comes in. This ratio relates your waist circumference to your height and is a way to identify a healthy waist circumference based on your height. It also proves to be a better predictor of a person's risk of developing and dying from heart disease than Body Mass Index (BMI). The goal is to make sure that your WHtR ratio is between .42 and .51.

To figure your WHtR, follow these steps:
  1. Measure the circumference of your waist (across or just above the belly button)
  2. Measure your height
  3. Divide the waist measurement by the height measurement.
Example: A person's waist measurement is 30 inches and their height is 70 inches. Dividing 30 by 70 gives this person a WHtR of .429 (which is considered healthy).

Waist-to-Hip Ratio (WHR)
Another helpful body measurement is the WHR, which has also been connected to a person's health. As with abdominal circumference and WHtR, a larger WHR is associated with increased risk of heart disease, stroke, and Type 2 diabetes. (3)

In general, a person's risk of developing heart disease (and high blood pressure, Type 2 diabetes, and stroke) increases when: (4)
  • A male's WHR goes above 1.0 (a WHR around .9 is ideal).
  • A female's WHR goes above 0.8 (a WHR around .7 is ideal).

To figure your WHR, follow these steps:
  1. Measure the circumference of your waist (across or just above the belly button)
  2. Measure the circumference of your hips (across the widest part of the buttocks)
  3. Divide the waist measurement by the hip measurement
Example: A female's waist measurement is 26 inches and her hips measure 38 inches. Dividing 27 by 38 gives this female a WHR of .68.

Conclusion
When visceral fat is used as long-term fat storage, then your body is experiencing dysfunction. If this dysfunction is not corrected, then decades of an expanding waistline indicate high odds of also developing heart disease, diabetes, and obesity. As such, your waistline can be used as a general window into your health.

The prescription for fixing belly fat is improved diet and lifestyle. If you make diet and lifestyle changes, and your waistline continues to be too big, then you're doing something that is preventing your body from healing (or you have bigger health problems). However, if your waistline does start to drop, then your changes are working and your belly fat will eventually disappear.

In my next post, I talk more about how you can reach your ideal body weight by simply using diet and exercise.

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