http://www.thelancet.com/journals/lancet/article/PIIS0140673606692519/abstract
Association of bodyweight with total mortality and with cardiovascular events in coronary artery disease: a systematic review of cohort studies
Abel Romero-Corral MD a, Victor M Montori MD b, Prof Virend K Somers MD a, Josef Korinek MD a, Randal J Thomas MD a, Thomas G Allison PhD a, Farouk Mookadam MD a and Francisco Lopez-Jimenez MD
Paul Ernsberger, PhD, Case Western Reserve School of Medicine:
Extremely obese 30-year-old have 40 years of life expectancy (versus 45 years of they were thin). Thus, to actually extend lifespan the surgery must keep weight off for life. This is not likely unless new operations are done every 5 to 10 years.
At any given time, tens of millions of Americans are on weight loss diets. Most will lose weight, but 95% or more will eventually gain the weight back and some will gain back more than they lost. Cycles of weight loss and regain can be harmful. Epidemiological studies show higher than expected rates of heart attacks and deaths among "yo-yo dieters". Why does losing and regaining weight seem to raise the risk of cardiovascular disease? What is the influence of diet composition during the weight loss and relapse phases?
Our studies are directed towards answering this question by using our own genetic animal model, the SHROB rat, which is both obese and has high blood pressure. These rats have a spontaneous gene knockout for the receptor for leptin, a hormone made by fat cells that regulates appetite and metabolism. When SHROB rats are made to lose and regain weight, their blood pressure soar even higher, they become even fatter, and heart and kidney disorders are exacerbated. Future studies will unravel the hormones and neurotransmitters involved in this weight cycling syndrome, identify diets that ameliorate the syndrome, discover genes that can modify the risk factors, and extend these studies to human patients. Additional studies will seek drug therapies that correct abnormalities in obesity, diabetes and high blood pressure. See Figure 1 below ---l1-imidazoline receptor signaling pathway (From Ernsberger, et al., 1997.)
http://www.case.edu/med/nutrition/ernsberger.html