updated 07/17/2013 AT 2:00 PM ET
•originally published 07/17/2013 AT 2:55 PM ET
Does weightlifting make you look like a body builder? Will crunches give you a flat belly? I’m going to separate the fitness facts from fiction.
MYTH #1: Working out means you can eat whatever you want
FACT: There are a couple of key reasons why this myth can cause us to gain weight. One is that we tend to overestimate the number of calories we burn when we work out.
It doesn’t help that some reports suggest that treadmills and other cardio machines overestimate, too – to the tune of up to 30 percent. Compounding the problem, intense (cardio) exercise can actually increase your appetite.
Moreover, we tend to underestimate the number of calories we take in when we eat. Not only does this disparity lead to weight gain, but when we exercise our hunger also increases. If we leave the gym ravenous and eat everything in sight then we’re cancelling out the good effects of the exercise and then some!
Overestimating calories burned + underestimating calories ingested + increase in hunger = almost certain weight gain.
MYTH #2: Lifting heavy weights will make you look like a bodybuilder
There are three primary factors that determine how much muscle someone can develop.
Number one is hormones. Women have less testosterone than men, therefore, women have smaller muscles than men.
Number two is diet. If you want to build a bigger house, you need extra building materials. Same goes for your body’s muscles, which means you need extra calories, protein, fat, carbohydrates. If you don’t increase your dietary intake, all the weight training in the world won’t make your muscles bigger.
And number three is exercise volume. Traditional “hypertrophy” or muscle-building workouts commonly used by bodybuilders, focus on onto to two body parts a day, and often use four to five exercises per body part, and four to five sets per exercise. That’s a whopping 16-25 sets for one body part per workout. That’s a lot!
In an interesting study at Central Michigan University, researchers had female participants do exercises on one arm, doing many reps using a light weight. On the other arm, they performed the same exercise, doing fewer reps with a heavier weight. After 10 weeks, the arm that used the heavy weights was stronger, but no bigger in size.
MYTH #3: Crunches and ab exercises will flatten your belly
Not only does doing 300 crunches a day not reduce that layer of fat over your stomach – they can actually create bad posture and create the illusion of a belly! Crunches mimic the posture we use when we’re sitting for much of the day, and the last thing we want to do is further develop that hunched position.
Also, crunches really only work the front surface of our abs, ignoring the rest of the muscles in the trunk. To get strong abs, try doing core exercises like a plank, trunk twist for your corset (transverse abs), side bends to work your obliques, and superman to work the all-important (and often forgotten) lower back – the foundation to great abs.
MYTH #4: Pilates and yoga lengthens your muscles
A muscle generally has two points of attachment to our body – an origin and an insertion. Short of actually cutting the muscle off of one of these attachment points, stretching it out, and reattaching it at a point further away, you cannot actually change the length of a muscle. While Pilates, or any exercise for that matter, cannot add length to your muscles, it can strengthen them and improve general posture, which can give the illusion of a longer, leaner physique.
MYTH #5: If you’re not sweating, you’re not getting a good workout
There are tons of factors that go into how much you sweat, including temperature and humidity, physical make-up, genetics and the clothes you’re wearing. Sweating is simply our body’s biological response to overheating; when sweat evaporates off our skin, it cools our body temperature.
So don’t worry about how much you do or don’t sweat – just keep moving!
Do you have any fitness myths you would like debunked? Tweet me @harleypasternak