Thursday, May 21, 2009
It's Good to be Fat!
Ok, just when you think you know something, another piece of evidence comes out that is 180 degrees different. While I think we all should question and test all of our assumptions, this is a bit far!
I know the fat vs fit debate has been going on for awhile, but arguing that being fat is better for survival is insane! Even a very thin person has enough fat for a long time as an energy supply. We know that fat cells are VERY active and they don't just sit around on their fat butts all day; they are actually sending and receiving hormonal signals.
The argument that there is only ONE type of heart disease is equally insane, as I would be very surprised if this panned out to be true. Physiology is not that simple.
Just for your reading, here is the source and an article from heart wire, so judge for yourself.
Mike T Nelson
Lavie CJ, Milani RV, Ventura HO. Obesity and cardiovascular disease. Risk factor, paradox, and impact of weight loss. J Am Coll Cardiol 2009; 53:1925–1932.
Obesity Paradox Probed in New Review
Despite being a key cause of heart disease, obesity appears to be protective in a range of cardiovascular problems, a new review concludes . But that doesn't mean people shouldn't try to lose weight, lead author on the paper, Dr Carl J Lavie (Ochsner Medical Center, New Orleans, LA), told heartwire . Indeed, patients who fare the best seem to be obese patients who manage to lose some weight, he said.
"First, obesity is a very strong risk factor and increases all types of heart disease, but second, once you get heart disease, the obese patients do better, so their prognosis is not doomsday," Lavie explained. "In fact, if you have obese patients with congestive heart failure or coronary heart disease or other heart disorders, those patients actually have a pretty good prognosis if they are treated well. But third, the ones who lose weight do even better."
According to Lavie, there is solid evidence to suggest that being overweight or obese may improve survival, not just in heart failure, but also in diseases like hypertension, coronary artery disease, and peripheral artery disease.
"There are a large number of cardiologists who don't even recognize that this is the case, and they are confused about it, too. It is honestly a confusing topic because if obesity is so bad, and it contributes to all cardiovascular risk factors and markedly increases the prevalence of developing heart disease of almost every type, then why, once they get it, do obese patients do better?"
The new review appears in the May 26, 2009 issue of the Journal of the American College of Cardiology (JACC) .
Obesity Likely Protects Through Various Mechanisms
The protective effects of excess weight have been best documented in heart-failure patients, where patients with higher body weight or percent body fat have demonstrated better event-free survival. In this setting, says Lavie, extra weight may function much the same way it does with cancer and other chronic diseases, by providing the body with additional fuel to help fight the disease.
Less well known is the relationship between obesity and hypertension, Lavie et al note. While people who are obese do have more hypertension, five papers spanning almost 20 years also point to the fact that obese people with hypertension seem to have lower mortality and/or lower stroke risk, despite less effective blood-pressure control, than do normal-weight people. In this setting, obese patients "may have a better prognosis in part because of having lower systemic vascular resistance and plasma renin activity compared with more lean hypertensive patients," Lavie et al write.
Also incompletely understood is the paradoxical relationship of obesity and coronary and peripheral artery diseases. Obesity is believed to play a causal role in the development of a number of major risk factors for arterial disease, among them hypertension, dyslipidemia, and diabetes, and is believed to be, in and of itself, a risk factor for atherosclerosis. But according to the JACC authors, there is also literature to suggest that overweight and obese coronary heart disease patients have a lower risk for mortality compared with under- and normal-weight coronary heart disease patients who have undergone revascularization procedures. A similar contradictory relationship has been seen in patients with peripheral artery disease.
Speaking with heartwire , Lavie emphasized that the protective effects of excess weight and excess fat likely function in different ways in different diseases. "We know that fat cells do a lot of bad things, but it's certainly conceivable that in advanced disease, the fat cell could have some beneficial effects. There's still a lot that needs to be known about this process."
Weight Loss Still Key
A key new piece of the puzzle that emerged in Lavie et al's review, however, is that weight loss, often touted as a way to reduce cardiovascular risk, appears to be a good thing in spite of the protective effects of extra weight.
"For people who follow this field, these kinds of findings have led them to question whether weight loss is good for heart-disease patients. . . . We found that the patients who do the best are the obese patients who lose weight."
This additional contradiction may be explained in part by the theory that heart disease in obese patients is likely "a different disease" than heart disease in lean people, in whom genetic factors are probably more important. "It may be that the obese person wouldn't have even gotten blocked arteries if [he] hadn't gained 70 pounds over a 30-year period," Lavie said. "The thin person who gets blocked arteries or congestive heart failure or high blood pressure is probably different from the obese patient who got the disease from becoming obese."
For now, he says, it's important particularly for the general public to appreciate that the "protective" effects of obesity in no way provide a rationale for weight gain. "Very clearly," he said, "if no one in our country became overweight or obese, heart-disease rates would go down dramatically."
For physicians, the data today are sufficiently comprehensive for them to encourage their overweight and obese patients to stay motivated to reduce their risk factors. That wasn't always the case, he added. "When people were finding this in their data, five and six years ago, they probably had some trouble getting their papers published, because it didn't make any sense."