Science is no match for your client’s sister’s boyfriend or that InstaTrainer.

Honestly, we’re pretty pissed off that we have to keep repeating some of this stuff. It’s 2021. We should be over this already.

Our job is to help people improve their health and fitness—to exercise more, eat better, and live a healthier life.

It’s a hard enough job without having to overcome a whole bunch of nonsense uninformed people and opportunistic marketers lead the general population to believe.

The following 10 myths retain their power because they keep getting repeated despite the very clear evidence to the contrary.

If we want to make a difference, we have to steer our clients away from bad ideas, myths, and misconceptions. This guide is a start.

Here they are, in no particular order:

The 10 Straight-Up Wrong Things People Still Believe About Fitness and Nutrition in 2022

  1. is the best diet for weight loss
  2. Exercise is bad for your immune system
  3. The key to weight loss: Eat a lot less and exercise a lot more
  4. Cardio is the only way to lose weight
  5. Every workout should be all-out
  6. Older men and women shouldn’t train hard
  7. Lifting weights makes someone bulky
  8. Stretching loosens tight muscles
  9. It’s only a deadlift if it’s from the floor
  10. Hiring a personal trainer will fix everything

1. is the best diet for weight loss

Another year, another diet.

Just in the low-carb category, we’ve gone from Atkins to South Beach to paleo, keto, and carnivore. We could create separate timelines for everything from low-fat to vegetarian to fasts and cleanses.

With each new fad, we learn yet again that no single diet is right for everyone, while some aren’t a good idea for anyone.

The reality is that there’s no magic diet, and just about every fad diet works the same way:

  1. Calorie restriction. If you eliminate an entire category of food—grains, fat, meat, dairy—you’ll have to eat less because you have fewer choices.
  2. Rules. Most diet plans either tell you what you can and can’t eat, or when you can or can’t eat. Either system takes the randomness out of food choices.
  3. Fewer processed foods. Just about every popular diet is based on whole or minimally processed foods, eliminating the snacks and baked goods you’re most likely to consume in mass quantities.
  4. Effort. With processed foods off the menu, you have to plan meals in advance, shop for the ingredients, and then invest time and effort into preparing the food. You’re putting  thought into every part of every meal.

The specifics of each diet are often irrelevant. Their main purpose is to give you a reason to make all these changes.

Sometimes the reason is completely legit and scientifically sound, especially if the client has a medical condition the diet is designed to address.

But sometimes it’s …  not.

Debunk it: Chances are, your client doesn’t completely understand the challenges of whichever fad diet they’re interested in. It’s on you to explain the pros and cons—tactfully.

First ask what they like about the diet. This not only keeps them from getting defensive, it gives you valuable intel about what they’re looking for in a nutrition plan.

Then dig into your client’s lifestyle. What are their habits? What do they like to eat, and when do they like to eat it?

From there the two of you can proceed as partners working toward a mutual goal: figuring out the best diet for them.

2. Exercise is bad for your immune system

One thing came back to life amidst the death and destruction of the pandemic in 2020: the myth that strenuous exercise makes you more susceptible to infection and illness.

Although it’s been disproven, you wouldn’t know it if you saw stories on social media about elite athletes infected with COVID-19.

That led some to erroneously conclude that inactivity made you less vulnerable to the virus, and “fit shaming” briefly became a trending topic.

Debunk it: Yes, it’s true that a bout of intense exercise, in or out of the gym, briefly and temporarily compromises the immune system’s ability to resist infection.

But that’s about it for bad news.

Exercise improves the immune system’s ability to fight infection in most individuals, in most circumstances, assuming normal recovery between workouts.

Something else that matters:

Health-promoting behaviors rarely happen in isolation. Someone who goes out of their way to exercise is also likely to eat a healthy diet (whatever they think that is), get plenty of sleep, not smoke, and pay attention to public health guidance about social distancing and wearing a mask in public.

All those things either strengthen the immune system, speed up recovery from infection, or prevent pathogens from reaching you in the first place.

3. The key to weight loss: Eat a lot less and exercise a lot more

We’ll start with two things that are true:

  1. You need a calorie deficit to lose weight.
  2. Eating less and exercising more are both ways to create a calorie deficit.

So what’s the problem with clients who want to speed up their results by doing both at the same time?

Debunk it: To put it simply, each of them is really hard on its own. Doing two really hard things simultaneously reduces the odds of your client succeeding with either of them. It’s a reason why so many resolutions fail.

Creating and maintaining a large calorie deficit requires a structured system that, at first, is time-consuming and stressful. (As we noted for Myth #1.)

Starting or ramping up an aggressive exercise routine on top of the reduced-calorie diet compounds that stress.

But let’s say your client starts with that exercise routine. Prolonged and strenuous training requires two things:

  • Adequate fuel
  • Adequate recovery

How does the client accomplish either, much less both, when they’ve cut their energy supply?

It’s better to frame ambitious exercise and diet goals as two things the client can do sequentially, rather than simultaneously.

Decide which is the client’s greater need, more exercise or less food, and start there.

You shouldn’t ignore the other area completely. Encourage the client who’s training hard to clean up their diet without cutting a lot of calories, and give the newly dieting client a solid training program without pushing them beyond their ability to recover.

When your client shows progress, you can expand your focus. Keep moving forward incrementally until your client achieves their goals and gains a sense of self-control.


When your client begins or ramps up a serious training program, they need food for fuel and recovery. Depriving the body of what it needs is a recipe for failure.

4. Cardio is the only way to lose weight

Visit any gym on any day in January and you’ll be hard-pressed to find an open treadmill, elliptical, stationary bike, or stairclimber.

It’s a sure sign the general public still believes cardiovascular exercise is the primary way to drop pounds. After all, a cardio machine keeps a running count of the calories you’ve burned, like exercise is a video game and the goal is to get the highest score.

The bigger problem is the idea that the number of calories you burn in workouts is the deciding factor in weight loss.

Debunk it: As we explained in this article about fat burning workouts, your body has multiple ways of fighting back:

  • Workouts that use a lot of energy often stimulate the appetite, and you not only replace the calories you burned, you may even eat more.
  • Thanks to a phenomenon called moral licensing, it’s easy to convince yourself that enduring long, tedious workouts means you can eat anything you want.
  • The longer or harder the workout, the less movement you’ll do outside the gym while you’re recovering. That compensatory decrease in non-exercise activity can negate the calories burned in the gym.

A good workout does more than just burn calories. It’s part of a training system, one in which your clients make incremental but significant improvements in strength, muscle quality, movement skill, and work capacity.

All those things leave them feeling better, which means they’ll move more outside the gym, and be less likely to overcompensate at mealtime.

5. Every workout should be all-out

This follows from the previous point, only this time, instead of judging workouts by the calories they burn, they assume the buckets of sweat they leave on the gym floor are proof of how much fat they’ve burned.

We understand their goals: They want to look good naked, and to look good naked they need to lose fat. We’re also entirely capable of delivering that result.

At issue is their belief that the intensity of workouts determines the results of those workouts.

Debunk it: High-intensity workouts are mostly fueled by glycogen, not fat. You’ll use a higher percentage of fat post-workout, when your metabolism is elevated. And that’s a nice benefit.

But that doesn’t mean training all-out, all the time, is the best way to maximize that benefit.

The harder the workouts, the higher the risk of injury or burnout. You also compromise progression and sacrifice every other benefit of training for the sake of feeling like a badass.


Going all out, all the time, makes your client more susceptible to injury and burnout, and often sacrifices form and progression.

6. Older men and women shouldn’t train hard

This one comes from a few different directions.

At different times, scientists have proposed that humans have a finite number of heartbeats or that aging was caused by the accumulation of free radicals. Seniors may also fear sudden cardiac death caused by exerting themselves.

Debunk it: The truth is that exercise prolongs life, prevents disease, and speeds up recovery from illness or injury. It also slows down age-related loss of muscle, bone, and functional abilities, and improves balance, coordination, and cognitive function.

You certainly need to be aware of your older clients' abilities and exercise history, and adjust your program accordingly.

Just keep in mind that, no matter the client’s age, the goal of training is to induce training effects—meaningful improvements in strength, endurance, and movement quality.

7. Lifting weights makes women bulky

To be fair, the industry has come a long way in dispelling this one. But you’ll still get a client who believes three-pound weights will give her a willowy body like Gwyneth Paltrow’s, while anything heavier will turn her into a tree stump.

You’re dealing with three overlapping myths here:

  1. A workout can change someone’s body type. So a skinny person’s workout will make you skinny, and a bulky person’s workout will make you bulky.
  2. Gaining muscle is easy and automatic. The fact very few people gain significant amounts of muscle despite years of serious training does little to dispel your client’s fear that she will be the exception.
  3. The only reason to train with weights is to get bigger. This one comes from a generation when gym culture mainly appealed to meatheads. But belief in this myth extends way beyond the people who belong to that generation.

Debunk it: Before you can tackle the “bulky” myth, or really any myth, keep this is in mind: It’s not just unprofessional to go right after your client’s beliefs, it’s unproductive.

Start with a simple acknowledgment that a lot of people fear unintentional mass-building.

Patiently explain how hard it is to build muscle. (If you’re a male trainer who’s not especially massive, you can use yourself as an example.) Describe the energy surplus it requires, and how even guys who want to get bigger struggle to eat enough to support that goal.

Then share some of the mountains of science-backed benefits linked to resistance training, like improvements in strength, mood, and metabolism.

That’s in addition to the anti-aging effects described for myth #6.

Your client will come around as long as you don’t throw her under a loaded barbell on the first day. Meet her where she is and go from there.


No, Virginia, there isn't a Muscle Fairy that magically transforms you into the Bride of Hulk if you lift a weight larger than your forearm.

8. Stretching loosens tight muscles

Just about every new client will have movement issues caused by tight muscles. They may ask you to stretch them. But that’s probably not what they need.

Debunk it: The problem with traditional stretching is that it only pulls on a given muscle, with no consideration for the mobility or stability of the joints surrounding it.

A more practical approach: Introduce corrective exercises that improve range of motion and joint function.

Consider these movements to open the hips:

The final intervention is self-myofascial release to improve blood flow.

The combination of corrective exercises, strengthening muscles at full length, and foam rolling will do more to alleviate tightness than stretching ever could.

9. It’s only a deadlift if it’s from the floor

The idea that every deadlift should start with the bar on the floor—a sentiment shared in weight rooms across generations and around the world—has led to more injuries than probably any other exercise myth.

Debunk it: A barbell, when loaded with Olympic plates, sits 8.75 inches off the floor. That specific measurement was chosen to avoid a very specific type of injury: If an Olympic weightlifter fell with the weights overhead, the bar wouldn’t crush his skull.

It makes sense as a safety measure for competitive weightlifters. But it makes no sense at all for every lifter to pull a bar from the exact same starting point regardless of their height, limb length, lever angles, or injury history.

For most clients, it’s best to start with the bar elevated on a rack, blocks, or weight plates. The hex bar’s elevated handles are an excellent option to load the movement for more advanced clients while minimizing injury risk.


Most clients should deadlift with the bar elevated on plates, blocks, or a rack.

10. Hiring a personal trainer will fix everything

For many of your clients, hiring you is a get-out-of-jail-free card. It means they can cheat on their diets or skip workouts, and it’s not their fault.

After all, they hired a trainer. What more can anyone expect them to do?

Debunk it: Yes, you need to stress the importance of following the plan, but you can also urge your client to spend more time with supportive people.

Warn them that achieving their goals means getting a bit outside their comfort zone—ending a meal before they’re completely full, for example, or showing up for workouts when they’d rather be just about anywhere else.

Stand up to a client who challenges you. Address their negativity. And if you see the client putting all the responsibility for their results on you, you may have to tell them to cut the crap and take ownership of their own fitness journey.

All these issues lead back to one overarching misperception: Having a program is the same as executing a program.

You can help them, but only if they’re willing to do what’s necessary to reach their goals.