Best and Worst Health Trends of 2013

Each year comes with its own unique brand of health trends. Some wind up being passing fad diets, while others prove surprisingly on point. The key to healthy living is knowing which trends are worth your time. To that end, here are the year's shape-up and slim-down trends we'd like to forget—and the ones we hope will stick around into 2014.

Whatever your favorite workout—be it Zumba, spinning, yoga, or jogging—you can now probably do it in a pool near you. And it's not just for show. By getting your sweat on in the water, you eliminate the joint-jolting and tiring impact of many exercises while adding all-over resistance for greater strength and weight-loss gains, according to the Stockholm University College of Physical Education and Sports. Bonus: People who do pool exercises enjoy their workouts more than those who stick to dry land, per research from Baylor University Medical Center.

Whether it involves running through foam-covered obstacles or getting splattered with colored powder, fun runs have it right: Fun is the ultimate motivator, according to Edward L. Deci, PhD, a motivational researcher and professor of psychology at the University of Rochester. People who work out for the pure joy of working out rather than for a result (think: lose those last five pounds) actually stick with workouts longer and reap better results, he says. So grab your girlfriends and sign up!

Somewhere between PETA's annual list of the sexiest vegan celebs and renowned food writer Mark Bittman's VB6: Eat Vegan Before 6:00 to Lose Weight and Restore Your Health…for Good, 2013 became the year of the vegan. Vegans tend to be thinner and have lower cholesterol and blood pressure than omnivores and vegetarians alike, according to a 2009 review in the American Journal of Clinical Nutrition. If you want to try an animal-product-free lifestyle—even just part time— make sure you get enough protein daily, advises Martica Heaner PhD, a nutritionist and exercise physiologist based in New York City. Try these vegan and vegetarian protein sources.

Ropes, hula-hoops, kickboxing moves, and even trampolines made their way into the yoga studio this year—and the combination caters to more than your attention span, says Melissa diLeonardo, an American Council on Exercise-certified personal trainer and a Life Fitness Master Trainer. By integrating non-yoga moves into your routine, you can train a wider variety of muscles for better total-body sculpting.

Now, in dozens of cities across the United States, exercise can actually save you time. So bypass traffic and get a bike pass: One four-year study of 822 adults found that bike commuters gain less weight over the years than car commuters. Besides toning your legs, increasing your heart rate, and strengthening your core, biking can seriously boost your energy. One study in Psychotherapy and Psychosomatics found that biking decreases fatigue by 65%.

Girls (even grown ones) just want to have fun! And playground workouts—from adult playground fitness parks across California to the jungle gym-inspired Synrgy360 stations in gyms—are designed to help them have just that. "As adults, we just don't play enough. Play is good for your body and mind. These workouts give us an opportunity to let loose and explore new ways of burning calories while having fun," diLeonardo says. Plus, with bars for climbing, ropes for pulling, and platforms for jumping, playground workouts strengthen your entire body through natural, multi-joint exercises to improve your fitness both in and out of the gym.

Shoe fanatics, rejoice! Now stores stock Zumba, indoor cycling, and even CrossFit shoes—and they do more than make you look like a pro. "Footwear designed for specific activities can help improve performance and provide additional support when executing certain movement patterns," diLeonardo says. For example, shoes designed for dance-inspired classes generally have more lateral support and less tread so you don't twist your knee mid-spin. If you are starting a new class, talk to your instructor about the right footwear for the exercises involved.

The Fast Diet

, The IF Diet, and The 5:2 Diet might sound like gimmicks, and they are definitely unintuitive, but a 2013 review in the British Journal of Diabetes and Vascular Disease suggests that fasting diets not only aid in weight loss but actually may help people with cardiovascular disease by decreasing inflammation, reducing blood pressure, and improving blood sugar and triglyceride levels. The key is following a healthy protocol, as some can lead to a binge-purge mentality, says dietician Alexandra Caspero, RD, owner of weight-management and sports-nutrition service delicious-knowledge. She advises talking to a nutritionist or healthcare provider to find the one that's right for you.

Increasingly more gyms are serving their cool-down with a side of spirits: Finish a class and you get an all-you-can-drink pass. "Alcohol during or following an exercise class is a definite no in my book," says diLeonardo, who emphasizes the need to drink water, not alcohol. Why? According to one study in the Journal of Applied Physiology, alcohol drains your muscles' levels of glycogen, their primary source of fuel. The effect: Your muscles don't have the energy they need to repair, grow stronger, and increase your metabolism. Basically, post-exercise sips negate your workout.

As if the Paleo Diet wasn't strict or unsustainable enough, this year people turned to the Whole30 Diet, which is basically an extremist "caveman" plan. The month-long program prohibits the consumption of fiber-filled legumes and whole grains, calcium- and vitamin D-rich dairy, and even some Paleo-approved foods like coffee, alcohol, and honey, all of which have been linked to improved health and longevity, Caspero says. While the strict plants-and-meat diet will surely spur weight loss by eliminating unhealthy refined sugars, the diet is far from sustainable—and isn't designed to be that way. So what happens after the month ends? You yo-yo. And while weight lost from extremely restricted diets is typically from a combination of fat and lean tissues, weight regained is typically 100% fat, she says.

This year, hot Pilates, hot barre, and even hot weightlifting classes have joined Bikram yoga in cranking up the heat. But for what? "You don't need the heat to get a good workout," says diLeonardo. One 2013 American Council on Exercise study found that increasing the temperature does not make you work any harder or burn any more calories. All of the sweat just makes you think you do, all while putting you at risk of dehydration, she says. Also, while the ACE study found that temperatures of up to 95 degrees are safe for a person with zero health issues, researchers warn that many classes turn up the temps as high as 115 degrees.

About one in three Americans are cutting down on or completely eliminating gluten, per a 2013 survey from The NPD Group. If you're one of them, read your nutrition labels. "Gluten-free foods aren't automatically better for you, and plenty of them can make you gain pounds," says Seattle-based certified nutritionist Deborah Enos. "Gluten helps to hold food together. When food manufacturers remove gluten, they add in fat and sugar to help the food maintain its shape." Plus, a 2012 review in the Journal of the Academy of Nutrition and Dietetics shows that a gluten-free diet has no benefit—and can even harm gut health—in people without celiac disease or a gluten intolerance.

Remember watching your mom jiggle her fat away with vibrating belts? Well, the vibration fad is back, but this time you stand on a pulsating platform to tone muscles, boost your metabolism, and reduce cellulite…or not. In one International Journal of Sports Medicine study, women who completed 24 weeks of whole-body vibration training did not lose fat.

Pushing yourself is great. But pushing yourself beyond your ability is counterproductive and dangerous. Unfortunately a slew of workout classes and DVDs tout exhaustion as the ultimate goal, sacrificing form for intensity and increasing your risk of injury, says performance enhancement specialist Martin Rooney. What's more, when working out at home to DVDs, it's challenging to know if you are keeping form even before fatigue sets in. Before signing up for any high-intensity interval classes (which we love!) or popping in a DVD, develop proper form with a personal or small-group trainer.

An example of why you should read into who's behind your eating plan, The Bulletproof Diet wasn't drafted by an MD or nutritionist. It was designed by a Silicon Valley investor and computer security professional who lost more than 100 pounds, according to the diet's website. While his personal weight-loss is certainly inspiring, it doesn't provide rock-solid scientific evidence to support recommendations to eat 4,000-plus calories a day, not exercise, and scoop butter into their morning coffee. If it sounds too good to be true, it probably is.