11 fitness 'truths' that are doing more harm than good

Whether you want to tone up, slim down, or give yourself a mood boost, you've likely taken a stab at tweaking your fitness routine.

Unfortunately, there's a lot of 'fitness' advice out there that won't help you meet your goals and could actually be doing you more harm than good.

For example, which matters more for weight loss: Exercise or diet?

Are marathons the best way to get fit?

The answers to these questions might surprise you.

Have some we missed? Send them along to science(at)businessinsider.com.

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Exercise is all that matters when it comes to losing weight fast.

Wrong. 

In the short-term, the bulk of research shows us that diet is far more important than simply upping your workout regimen if you want to start shedding pounds.

"Studies tend to show that in terms of weight loss, diet plays a much bigger role than exercise," Philip Stanforth, an exercise scientist at the University of Texas and the executive director of the Fitness Institute of Texas, told us.

Over the long-term, though, research suggests that regular workouts do become more important for staying fit. "When you look at people who've lost weight and are also managing to keep it off, exercise is important," said Stanforth.

Weight training will turn fat into muscle.

Nope. Lifting weights won't magically turn your flab lean. Unfortunately, body fat cannot become muscle. But weight training will help you build muscle tissue, which will thicken underneath any fat above it.

Early morning is the only time you should work out.

Afternoon or evening are likely nearly as good for you as early-morning workouts, according to several studies.

But — some research suggests that working out first thing each dayhelps speed weight loss and boost energy levels by priming the body for an all-day fat burn.

Plus, getting more daylight may play an important role in shedding pounds. By making sure we align our internal clocks, or circadian rhythms, with the natural world, we may help give our metabolisms a boost. One recent study showed that people who basked in bright sunlight within two hours after waking tended to be thinner and better able to manage their weight than people who didn't get any natural light, regardless of what they ate throughout the day.

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