As a cardiologist with a strong interest in prevention, eating better and exercising more are a cornerstone of my prevention prescription. But every once in a while, I am intrigued by new scientific studies that provide data which contradict, challenge, or just clarify our basic understanding of how the body works. For example, a recently published paper found that consuming saturated fat from meat does not appear to increase our risk of heart disease – a later study specified that eating processed meat appears to account for the perception of increased risk. We need to be flexible with our recommendations and maintain an open mind as physicians so we can best counsel our patients and provide a consistent (and accurate) public health message.
One of the tougher things to negotiate is the so-called “obesity paradox.” This is the idea – supported by research – that mildly obese people (body mass index 30-35) with heart disease may do as well or even better than lower weight individuals. They do not appear to experience increased risk after heart surgery, or for future hospitalizations from congestive heart failure. They may even live longer. So what does this mean? We already know from other studies that obesity is a cardiac risk factor…so can being mildly obese somehow be protective once you already have been diagnosed with heart disease? Does this suggest that we should watch our weight until we have a heart attack, but then feel free to go nuts and gain weight without worry?
Probably not. There may be some confounders that can explain this apparent paradox. In general, people who are the sickest – from any cause – tend to lose weight rather than gain it. Therefore, less serious heart disease will be less likely to cause someone to lose weight and become cachectic. Another possible variable is aggressiveness of care. If an obese person with chest pain is more likely to be taken seriously by a paramedic than a normal weight individual, the obese individual might receive better care and therefore be expected to have better outcomes.
A key point is that while mild obesity may not be associated with worse outcomes, having a body mass index greater than 35 continues to be associated with significant risk, even after a diagnosis of heart disease. It’s true that we tend to focus most on numbers – like weight, body mass index, fat percentage – rather than on lifestyle choices like eating more fiber, fruit, and fish, or increasing our frequency and intensity of activity and exercise. We already know that the fittest individuals can safely fall in the “overweight” category of body mass index (25-30) without evidence of significantly increased risk. So it may be that the “obesity paradox” is more observation rather than a prescription that should significantly impact that we way we live our lives. And it suggests that doctors might focus more on lifestyle choices rather than just looking at the bottom line – in more ways than one!
James Beckerman, MD is a cardiologist in Portland, Oregon. He is the http://www.WebMD.com Heart Expert and runs the Weight Loss forum on http://www.MedHelp.org. He is the author of The Flex Diet, and evidence-based approach to healthy weight loss which emphasizes personalization and choice – it bends so that you don’t break. Read more at http://www.theflexdiet.com.
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