Posted by: isaaph | October 29, 2007

A Follow Up To “Fat and fit, lean but unfit?”

Here’s the latest from Dr. Rafael Castillo

A rejoinder on being fat yet fit, lean but unfit

By Rafael Castillo, MD


MANILA, Philippines—We received a good number of feedback and questions regarding last week’s column on being fat yet fit, and lean but unfit. A rejoinder is in order.

Firstly, we inadvertently exchanged the values for the waist circumference (WC) measurement for Asian men and women. The ideal values should be less than 90 centimeters (35.5 inches) in men and less than 80 centimeters (31.5 inches) in women. Caucasian cut-off values are higher: approximately 40 inches for men, and 35.5 inches for women.

Different values

Why different values for Asians and Caucasians? It’s not arbitrary and definitely nothing verging on racism. It’s borne out of hard research data that ethnic differences exist with regard to the relationship of the waist circumference and cardiovascular risk, such that measurements above these identified cut-off values are associated with a significant increase in the risk of developing stroke, heart attack and other cardiovascular complications.

Researchers have shown this initially in Asians living in America. If they used the accepted cut-off values for Caucasians in those with Asian ethnicity, what would appear to be a marginally increased waist circumference of 37-39 inches in men and 32-35 inches in women were already associated with greater risk. This finding has been validated by other studies conducted in Asia.

The reason for this is that Asians are inherently predisposed to be more insulin resistant than Caucasians. Insulin is not only responsible for sugar metabolism but it also governs fat metabolism and distribution. Many believe that significant abdominal obesity is one of the tell-tale signs of insulin resistance, which is identified as the culprit leading to hypertension, diabetes, cholesterol problems and obesity.

Identifying high-risk patients

Galo Barrios texted his question if a normal waist circumference (WC) will rule out the metabolic syndrome. Increased WC is just one of five criteria for identifying high-risk patients with the metabolic syndrome. The other four criteria are the blood pressure (higher than 130/85 mmHg), blood sugar level (higher than 100 mg/dl), a low high-density cholesterol or the good cholesterol (lower than 40 mg/dl in men and less than 50 mg/dl in women) and high triglycerides (more than 150 mg/dl). Three out of five make a diagnosis of metabolic syndrome.

Although one big international medical organization is proposing that the syndrome should never be diagnosed without obesity, indicated by increased WC, the prevailing opinion is that any three of the five criteria can already strongly identify patients with metabolic syndrome.

Body fat indicators

Marissa Reyes from Merville Park, Parañaque, asked about the waist-hip ratio (WHR) and the body mass index (BMI).

The WHR and BMI are also indicators of body fat, but most clinicians now prefer to use the waist circumference for practical reasons. It’s easier to determine, requiring only one measurement and not entailing any computation, as the WHR and the BMI do.

To determine the WHR, divide the WC by the hip measurement. It should not be more than 1 (preferably 0.9) in men and not more than 0.8 (preferably 0.7) in women. So one may still be overweight but if his/her proportions are still okay, as shown by the WHR, then the associated risk may still be not significant. Conversely, the seemingly normal-weight individual with bulging belly—hence, higher WCR—may be at a higher risk.

The BMI, expressed as kg/m2, is computed by dividing the weight in kilogram by the height in meter squared. In Caucasians, a BMI higher than 25 is considered overweight, while in Filipinos and other Asians, a BMI higher than 23 is already considered overweight.

There are some inherent limitations in using the BMI to evaluate fatness and leanness. As the term implies, it measures total body mass which not only includes fat but muscle and bone as well. Hence, it can be easily distorted by such factors as fitness level, muscle mass, bone structure, gender and again, ethnicity.

In athletes, for example, the muscle is heavier than fat. So they may seem overweight based on their BMI measurement. Hence, the BMI may overestimate fatness in those with more lean body mass like the athletes, while underestimating fatness in those with less lean body mass such as in the elderly.

Healthy lifestyle

Singapore-based Alex Lip, a manager at Omron Singapore Pte Ltd., gave me an interesting feedback. He calls seemingly lean individuals with increased fat mass as having “hidden obesity.” This is why his company has developed modern sensitive devices to detect BMI and abdominal obesity accurately.

So how do we remain fat yet fit and prevent becoming lean but unfit? Nothing beats the good old healthy lifestyle. Eating a high-fiber low-fat diet, avoiding fast foods like the plague, avoiding being sedentary especially after retirement, doing regular exercise on most days of the week (preferably daily), nonsmoking and avoiding those who do, drinking no more than an ounce of alcohol a day, and managing stress effectively all go a long way to ensure a healthy direction far away from the emergency room or the morgue.

Source: Philippine Daily Inquirer


Responses

  1. Dr. Castillo, “Ooops, my bad! I said fat wasn’t unhealthy!” (not a real quote, but a sarcastic jest at his sudden turn-around about fat and health)


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