What diet did you do this for like a yo- yo? That is, rapid weight down but quickly rose again like a yo-yo. Be careful! According to researcher Dr. Claire Duvermoy, a cardiologist at the University of Michigan (USA), weight fluctuated up and down can increase the risk of heart disease. Because the weight is down ride lower levels of good cholesterol (HDL) and interfere with blood flow to the heart, so it can trigger a stroke or heart attack. To be avoided from the effects of yo-yo dieting, it is advisable not to diet excessively. Strict diet is not only detrimental to health, but also difficult to maintain. According to WHO, weight loss is declared safe is about 1-1.5 kg per week.