Rise And Fall Of 8 So-Called Healthy Foods Slideshow

Are eggs good or bad for you? Most studies regarding the healthfulness of eggs have concluded that they're soundly nutritious; however that notion does come with a couple of caveats. Citing a 2008 study published in The American Journal of Clinical Nutrition that observed 21,300 men over a 20-year period, Web MD writes, "After adjusting for other risk factors, men who reported eating seven or more eggs per week were 23 percent more likely to die of any cause during the study; the risk rose among those with diabetes." However, eating up to six eggs per week showed no increase in health risks. 

Meanwhile, in January 2012, the Mayo Clinic's Thomas Behrenbeck, M.D., Ph.D., responded to a question about how eggs affect cholesterol levels by saying, "Although eating too many eggs can increase your cholesterol, eating four egg yolks or fewer on a weekly basis hasn't been found to increase your risk of heart disease."

Because peanut butter is high in saturated fat (and tastes so good), it must be bad for you, right? Not so fast, says Walter C. Willett, M.D., in the July 2009 edition of the Harvard Heart Letter: "Over the years, numerous studies have shown that people who regularly include nuts or peanut butter in their diets are less likely to develop heart disease or type 2 diabetes than those who rarely eat nuts."

An earlier study, conducted in 2008 by the American Journal of Respiratory and Critical Care Medicine concluded that pregnant women who eat peanuts or peanut butter are more likely to increase their child's development of asthma by 50 percent. But since this is the only research of it's kind to be conducted the conclusions must be taken with a grain of salt.   

Thanks to the resurgence in popularity of the Atkins Diet and similar programs encouraging a low-carb, high-fat meal regimen, a number of studies have taken a closer look at the health effects of certain processed meats (bacon, sausages, cold cuts). In 2010, The Globe and Mail in London reported on a study published by the American Journal of Clinical Nutrition, which concluded that consuming foods high in saturated fats have no link to increased rates of heart disease.

On the other hand, CBS News detailed another 2010 study by the Harvard School of Public Health, which found that eating bacon, sausage, and hot dogs can increase the risk of heart disease by 42 percent (and diabetes by 19 percent). According to Renata Micha, author of the study, "Processed meats such as bacon, salami, sausages, hot dogs, and processed deli meats may be the most important to avoid."

Does consuming food and beverages containing artificial sweeteners — such as Diet Coke, yogurt, ice cream, jams, and chewing gum — present a trade-off between weight loss and an increased risk of cancer? The verdict is still out, says the National Cancer Institute: "Questions about artificial sweeteners and cancer arose when early studies showed that cyclamate in combination with saccharin caused bladder cancer in laboratory animals. However, results from subsequent carcinogenicity studies (studies that examine whether a substance can cause cancer) of these sweeteners have not provided clear evidence of an association with cancer in humans. Similarly, studies of other FDA-approved sweeteners have not demonstrated clear evidence of an association with cancer in humans."

Contrary to popular belief, going back to the saturated fat discussion from the peanut butter slide, Weighty Matters cites an American Journal of Clinical Nutrition meta-analysis published in 2010 that says saturated fats (read: butter) are not tied to heart disease. The research considered 21 studies over a span of 23 years that looked at 347,747 subjects and found virtually zero effect of saturated fat intake on heart disease, stroke, or cardiovascular disease. 

According to a recently published Web MD feature on red meat: "A National Institutes of Health-AARP study of more than a half-million older Americans concluded that people who ate the most red meat and processed meat over a 10-year-period were likely to die sooner than those who ate smaller amounts. Those who ate about 4 ounces of red meat a day were more likely to die of cancer or heart disease than those who ate the least, about a half-ounce a day. Epidemiologists classified the increased risk as 'modest' in the study." There are some benefits to red meat, though, Web MD continues, noting that it is high in iron and that it supplies vitamin B12, zinc, and protein. The feature suggests that it's best to consume red meat in about 3-ounce servings.

A similar study conducted by the Harvard School of Public Health in 2011 concluded that there is a strong association between regular consumption of red meats (both processed and unprocessed) and increased risks of developing type 2 diabetes. 

Chocolate has to be terrible for you, right? Hasn't it been scientifically proven that anything that tastes so good will ultimately have drastic health implications? Shockingly no, says a 2011 Harvard Medical School study detailed by The Crimson. The study concludes "that consuming chocolate lowers blood pressure, improves cholesterol levels, and may reduce the risk of diabetes."

However, given the levels of sugar and caffeine present in dark and milk chocolate, it's probably still best to enjoy the health benefits and exquisite taste of chocolate in moderation. 

Real Beauty examines conflicting studies about the role cheese should play in your diet if you are trying to lose weight: "A new study in Nutrition & Metabolism, funded by the National Dairy Council, suggests that cheese and other dairy foods may help prevent weight gain after dieting; another study found that regular cheese eaters gained less weight over time than those who ate cheese less often. But other studies, including one from Johns Hopkins in 2008, have found that people who eat more cheese tend to be more overweight."

Another study published in a 2011 edition of the American Journal of Clinical Nutrition concluded that when consumed in large quantities, cheese can help lower LDL-cholesterol concentrations. The belief is that the high calcium content found in cheese is responsible for this outcome.