1. Calorie restriction
For decades — and especially since 2009, when an encouraging study on the topic was published — some scientists have believed that eating a lot less than normal was the key to a longer, healthier life. But a recent study found that monkeys fed a restricted diet of about 30 percent fewer calories than normal didn't live any longer than monkeys allowed to eat whatever they wanted. So starving yourself may not be the path to eternal life — which may be good news, because the no-food diet sounds like the least fun fad ever.
2. Antioxidants
Antioxidants, compounds found in fruits and vegetables and purported to protect against cell damage, were a huge health buzzword from the nineties to the mid-2000s. Scientists thought they might prevent cancer and extend life. But then research found that not only did they not protect against cancer, they might shorten life and interfere with cancer treatment. Sorry, Pom.
3. Fish oil
Fish oil has been billed as a cure-all for everything from heart problems to ADD. But a 2010 study found that taking fish oil supplements didn't actually protect at-risk people from heart attacks. And another study debunked previous claims that taking fish oil during pregnancy made babies smarter. This doesn't mean fish oil is good for nothing, but its reputation as a panacea has been tarnished.
4. Vegetables
This one is a big bummer, because everyone knows vegetables are healthy! And they may be, but a number of studies in the past decade have shown that they don't prevent cancer, or keep cancer from coming back. They could still improve heart health, but veggies may not be the awesome disease-preventing machines they were once believed to be.
5. Low-carb diets
Low-carb diets have been touted not just for weight loss, but for heart health too. However, a 2010 study found that people who replaced carbs with animal fats and proteins died sooner than those who just kept eating bread. And this year, researchers found that a high-protein, low-carb diet increased the risk of heart disease. Others are questioning whether such diets really lead to more weight loss than low-fat alternatives.
6. Red wine
There's still hope for red wine — for instance, new research suggests it might be good for digestion. But does it extend life? That's less clear. A compound called resveratrol, found in the beverage, has been making headlines in the last five years as a way to extend life and even counteract the harm done by an unhealthy diet. But the most famous study suggesting this affect was done on mice given huge doses of resveratrol — a human would have to drink 750 to 1,500 bottles of wine a day to get the same amount. So while researchers are still looking into ways of harnessing the benefits of resveratrol, drinking normal red wine will probably not make you immortal.