When fitness folklore becomes treated as fact you risk damaging your performance and health. Self test to see what you think you know.

Myth 1: YOU GET FATTER AS YOU AGE BECAUSE OF A SLOW METABOLISM

There’s little question your metabolism does indeed slow as you age, so this is definitely part of the reason why you can gain weight as you age. However, it is one of the smallest reasons and it’s a bit more complex than it seems.

Firstly, yes, your metabolism does slow as you age. But it’s a slow process that can happen at the rate of 10% per decade. Even 10% per decade is just 1% per year, that’s not exactly throwing the pounds on at any rate.

Secondly, most of this decline is from a loss of muscle mass. If you’re committed to resistance training and staying active, you can prevent the vast majority of this decline.

Thirdly, failing to stay active is one of the key factors in weight gain with age, with metabolic slowing, muscle mass-related or not, paling by comparison. Thus, by resistance training and staying active, you’re fighting off two out of the three main reasons people gain weight as they age. The last main reason people gain weight as they age is that they are less active, have a lower metabolism, but continue to eat as they used to when they were younger. By watching your weight and eating a bit less if you gain an appreciable amount of bodyweight, you can leverage physical activity and resistance training against the probability of weight gain and reduce it by a huge margin.

So yes, metabolism slowing is a thing, but it’s largely preventable and almost completely beside the point compared with reduced activity and excessive eating.

Myth 2: TO STAY IN SHAPE YOU ONLY NEED TRAIN 2-3 TIMES A WEEK

Yes, training only a few times a week will get you in some kind of shape and keep you there. Will it be an elite athlete shape that turns heads? Almost certainly not. However, can you be lean, muscular, and quite healthy by training only that much? With a very close watch on your diet, absolutely. It’s probably the bare minimum you can do, so aim to hit this requirement but do more.

Myth 3: IT’S MORE EFFECTIVE TO TRAIN FIRST THING IN THE MORNING

You should train when you are most likely to be consistent for success. Research at Northumbria University discovered guys burnt up to 20% more body fat by exercising in the morning on an empty stomach. When you’re exercising in a fasted state, your body has no other option but to draw energy from your stored fat reserves. But you can achieve this if you abstain from eating, it’s not a time of day thing.

Myth 4: LIFTING WEIGHTS TURNS FAT INTO MUSCLE

Fat is a completely different type of tissue than muscle. You can no more turn fat into muscle than you can turn your liver into your kidneys.

Myth 5: RUNNING A MARATHON IS A GREAT WAY TO BE FIT AND LOSE WEIGHT

Training for a marathon is absolutely a great way to be fit and get into shape while losing weight. But many people just aren’t built to run long distance, whether physiologically, anatomically, or psychologically. If distance running is your thing and you can do it safely and consistently, by all means go for it. However, if you prefer other ways of being active, don’t fall for the notion that training for a marathon is the only way to get in shape.

Myth 6: THE DEEP SQUAT IS BAD FOR YOU KNEES AND DEADLIFTING IS BAD FOR YOUR BACK

With improper technique, deadlifting heavy is very bad for your back and squatting heavy is bad for your knees. With proper technique, however, deep squats make your knees stronger and deadlifts make your back less likely to be injured.

Myth 7: YOU NEED TO SWEAT FOR EXERCISE TO COUNT

You can actually complete a ton of physical activity without ever breaking a sweat. Hours of very light work (gardening, playing with kids, riding a bike at a leisurely pace, taking a walk, etc.) can add up to lots of calorie burning and lead to weight loss and health improvement. That being said, there are unique health benefits of occasionally (several times per week or more, ideally) working very hard. And yes, that means sweating is expected during those times, or you probably aren’t working hard enough.

Myth 8: MACHINES ARE SAFER THAN FREE WEIGHTS

If you don’t know what you’re doing, then this is absolutely the case. If you know what you’re doing or have a trainer that does, the reverse is more likely to be true, with free weights probably getting an edge in most outcomes, especially real-world strength and mobility improvements.

Myth 9: BCAAS ARE THE SAME AS PROTEIN POWDER

Unfortunately, they are anything but the same. BCAAs are only three kinds of amino acids (Leucine, Valine, and Isoleucine). High quality protein powders have up to 20 different kinds of aminos, nine of which your body can’t make itself and needs to get from food. While BCAAs most certainly do have their benefits, whole protein powders have all of those benefits and then some. Whey protein might be a little heavier in your stomach so BCAAs could be a little easier to drink close to and during a workout.

Myth 10: BIG MUSCLES ARE STRONG MUSCLES

All things being equal, bigger muscles are stronger muscles because they literally have more machinery to generate force. Because of anthropometric technique, the nervous system, and other differences, not all more muscular individuals will be stronger than less muscular ones, but on average, they will be much stronger. There are weight classes in powerlifting for a reason. If you work on getting bigger muscles, a few months after you gain the size and return to strength training (as opposed to muscle growth training, which typically uses slightly lighter weights), you’ll almost certainly be stronger.

EXPERT:  Dr. Mike Israetel is the team USA Weightlifting Consultant co-founder and chief sport scientist of Renaissance Periodization (renaissanceperiodization.com)