Some health tips have value; others are a waste of time.

Everywhere we turn these days, it seems there’s a social media feed, newspaper article, or friend touting a new supplement, diet plan, or exercise you should try. Some of these tips have merit, and some are just, dare we say, fake health news. Here are six popular health trends, demystified:

1. Include probiotics in your diet. Probiotics are microorganisms that help balance the ratio of good to bad bacteria in your microbiome (the trillions of bacteria, viruses and fungi that live in your gut). According to several doctors, consuming probiotics is a good idea, especially for people who take (or have taken) antibiotics. To get probiotics, you can take a probiotic supplement. Or, you can get them from some fermented foods, including yogurt, kefir, sauerkraut, kombucha, pickles, and sourdough bread. 

2. Take a multi-vitamin for maximum health and immunity. It’s best to get nutrition from food. But for the many people who don’t get the vitamins and minerals they need from their diets, a daily multivitamin supplement can help provide nutritional insurance. And for most people, they are safe. Ultimately, it’s best to talk to your health care provider about whether a multivitamin is a good idea for you.

3. Always stretch before you exercise. “It depends on the type of exercise you are about to do, you, your goals, and the type of stretching you’re doing,” says manual therapist and movement coach Aaron Alexander. According to the American Council on Exercise, static stretching (the kind you did before gym in high school, like hamstring stretches and child’s pose), are best done after exercise, when your body is warm.  Alexander also reminds people to stretch throughout the day. “Every time you squat down to pick something up or reach high to get something out of a cabinet, stretch,” he says. 

4. Weigh yourself every day. It depends. Some people avoid daily weigh-ins because they get discouraged when the number on the scale doesn’t change. Actions as simple as drinking (or skipping) a glass of water can cause day-to-day variation in your weight. But if you’re trying to drop pounds, research shows hopping on the scale once a day may be a good idea. In one study, researchers followed 1,042 adults for one year. They found those who weighed themselves once a week did not lose weight, and those who stepped on the scale six to seven times a week averaged a weight loss of 1.7 percent. The bottom line: If you’re trying to lose weight, weigh yourself daily. If you’re not, you can hop on the scale less frequently.

5. The best time of day to work out is morning. Not only will you burn more stored fat when you work out in the a.m., you’ll also set yourself up for habitual exercise. A recent study published in the Journal of Physiology found that exercising at 7 a.m. shifts your body clock earlier, making you feel more alert in the morning and sleepier earlier in the evening, which sets you up for a good night’s sleep. Will a full night of zzzs, you’ll be more apt to get up early and do it all over again. The same study also found it’s easier to stick to healthy habits when you do them in the morning hours.

6. It’s important to include a ‘rest day’ in your exercise plan. Not so, says Alexander. Instead, he recommends an active, switch-it-up day. “If you usually lift weights, instead, go for a hike, play tennis, or take a yoga class—keep your body moving, but do it in a different way,” he says.