For every great piece of weight-loss advice out there, it seems there are no fewer than a dozen horrible ones—myths based on questionable pseudoscience, misinformation, and straight-up sales gimmicks.
These myths do more than sabotage your weight-loss efforts—they may even put your health on the line. And let’s be honest: in a world where everyone from your neighbor to your social media feed has an opinion on what you should eat, it’s tough to separate fact from fiction. We asked seven top trainers and nutritionists to ID the biggest myths keeping people from hitting their healthy-living goals. Plus, simple strategies for weight loss that lasts.
Myth #1: Eliminating Whole Food Groups Can Help You Lose Weight
Whether it’s dairy, gluten, or anything else—unless you have a dietitian- or physician-diagnosed intolerance to a certain food, there is no physiological reason to cut it out entirely, says Abby Langer, R.D., a dietitian and nutrition counselor based in Canada. And doing so could risk missing out on vital nutrients such as the calcium and vitamin D in dairy, and heart- and weight-friendly fiber in whole grains. “Plus, when people lose weight by cutting out an entire food group, it’s usually because they’re simply eating less overall,” she says. “Unless you can sustain such an eating style, or any change you make to lose weight, expect the weight to return once you go back to your old habits.”
What This Really Means for You
Here’s the thing: when you eliminate an entire food group without a real medical reason, you’re not just limiting what you eat—you’re limiting the variety of nutrients your body needs to thrive. Think about it this way:
- Cutting dairy? You might miss out on calcium for bone health, vitamin D for immune function, and protein for muscle maintenance.
- Going gluten-free without celiac disease? Many whole-grain foods contain B vitamins, iron, and fiber that are harder to get elsewhere.
- Avoiding all fats? We’ll get to that one in a minute—but spoiler alert: your brain and hormones need healthy fats to function.
The real kicker? Most people who “successfully” lose weight by eliminating food groups end up gaining it back once they reintroduce those foods. That’s not a failure of willpower—it’s just what happens when you rely on restriction instead of building sustainable habits.
The Fix: “Consider the individual foods—such as sugary drinks, fried foods, and alcohol—of which you should eat less,” Langer says. (Remember: A healthy diet mentality allows for these foods in moderation!) Where applicable, replace them with whole foods. For example, instead of nixing pasta entirely, sub out refined white pasta for whole-grain varieties.
A few simple swaps to try:
- White rice → brown rice or quinoa
- Sugary cereal → oatmeal with fresh fruit
- Soda → sparkling water with a splash of juice
- Packaged snacks → nuts or veggies with hummus
Myth #2: You Can Spot Reduce Fat
“It would be great if training your abs would help you lose that extra belly fat, but this just isn’t the case,” says Hannah Davis, C.S.C.S. a Tennessee-based strength coach and trainer. “When you lose fat, you lose it equally from your entire body.” Of course, some of us naturally lose fat in some areas more quickly than in others, but you can’t change your genetic makeup. What’s more, since “spot reduction” exercises like crunches recruit relatively few muscles, they burn minimal calories and have little to no effect on your metabolic rate (your natural calorie-burn rate), which is largely determined by the amount of muscle you have on your frame.
Why This Myth Persists
This one is so sticky because doing ab exercises genuinely feels like it should work. Your core is burning, you’re sweating, you can practically feel your midsection getting tighter, right? Unfortunately, that burn is just your muscles working—not fat melting away from that specific area.
Your body decides where it stores and burns fat based on genetics, hormones, and other factors that are largely outside your control. Some people lose face fat first; others notice changes in their legs before anywhere else. It’s frustrating, but it’s just how our bodies work.
Related: 5 Metabolism Myths—Busted
The Fix: Rather than performing ab exercises because they’ll burn up belly fat (they won’t), focus on building a strong core, which is essential for your overall fitness, Davis says. A strong core helps with everything from better posture to injury prevention to more powerful performance in other exercises.
And, when it comes to promoting overall weight loss, your best bets are large multi-joint exercises that work and build lots of muscles at once. Think: squats, lunges, and burpees. Here are a few more compound movements worth adding to your routine:
- Deadlifts
- Push-ups
- Rows
- Step-ups
- Mountain climbers
Myth #3: Eating Fat Makes You Fat
“Eating too many calories, which could just as easily be from protein or carbs as from fat, is what leads to weight gain,” says Kelly Pritchett, Ph.D., R.D., C.S.S.D., assistant professor of nutrition and exercise science at Central Washington University. Sure, fats do contain more calories per gram (they have nine calories per gram, while carbs and protein have four), so your servings of healthy fats likely need to be a bit smaller than those of carbs or protein. But that’s it. There’s no need to fear eating fats altogether, she says. And, on the flip side, eating too little fat can cause you to overdo it on total calories, since fat keeps you full and satisfied longer. Too little fat can also have negative effects on your heart, brain, and overall health. After all, two polyunsaturated fatty acids that are vital to health, omega-3s and omega-6s, cannot be produced by the body, and can only be obtained through your diet.
The Satiety Factor
Here’s something else to keep in mind: when you cut fat too drastically, you often end up hungry all the time. Fat is incredibly satiating—it slows down digestion and helps you feel full for hours. Ever notice how a plain salad leaves you ravenous an hour later, but adding some avocado or olive oil keeps you satisfied until dinner? That’s the power of healthy fats at work.
Plus, many fat-free or low-fat processed foods compensate for flavor loss by adding extra sugar. So you might think you’re making a healthier choice, but you’re actually trading one problem for another.
The Fix: Get your fat from whole foods like nuts, avocado, salmon, milk, eggs, and grass-fed beef as opposed to fast foods, fried anything, or processed baked goods and pizzas. “Still, whatever the fat source you’re eating, keep your serving sizes in mind,” Pritchett says. Read the food’s label if you’re not sure what a healthy serving looks like. (Think a handful of nuts, a third of an avocado, or a thumb of butter or cheese.)
Quick reference for healthy fat portions:
- Nuts/seeds: About a small handful (1 oz)
- Nut butter: 2 tablespoons
- Avocado: ⅓ to ½ of a medium avocado
- Olive oil: 1 tablespoon
- Cheese: About the size of your thumb
Myth #4: Cardio Is The Workout King Of Fat Loss
“This is a huge myth, and especially affects women who have been taught that spending all of their time doing cardio is the key to weight loss and improving body composition,” says Kourtney Thomas, C.S.C.S., C.P.T., a St. Louis-based online and personal trainer. But here’s the thing: Building muscle is critical to optimizing your basal metabolic rate, the number of calories you burn per day by simply living and breathing. While strength training burns calories and builds muscle, copious amounts of cardio can actually burn existing muscle, which is counterproductive to your weight-loss efforts.
The Muscle-Metabolism Connection
Think of muscle as your body’s engine. The more muscle you have, the bigger the engine, and the more fuel (calories) you burn even when you’re just sitting on the couch watching TV. When you rely solely on cardio—especially long, steady-state sessions—you might actually be shrinking that engine over time.
This doesn’t mean cardio is bad! It’s fantastic for your heart, mood, and endurance. But if healthy weight management is your goal, strength training deserves a starring role in your routine, not just a cameo.
The Fix: It’s important to have a well-rounded fitness routine, so don’t cut out cardio altogether—interval-based cardio like sprints can be really great for fat loss—but focus first and foremost on strength. Whether it’s a 30-minute metabolic-style workout (like intervals on a cardio machine or a bodyweight circuit), a powerlifting workout, or an hour-long body part split routine, prioritizing intelligent lifting over 45 minutes on the elliptical will go a long way in helping you achieve a healthy weight, Thomas says.
Not sure where to start with strength training? Here’s a simple beginner split:
- Day 1: Lower body (squats, lunges, deadlifts)
- Day 2: Upper body (push-ups, rows, overhead press)
- Day 3: Rest or light cardio
- Repeat
Related: Find the supplement that fits your weight-management plan.
Myth #5: You Need To Cut Carbs To Lose Weight
Just because you can lose weight by cutting or reducing carbs doesn’t mean that it’s the only way to do it, or that it’s necessarily healthy. Carbs are your body’s preferred form of fuel, and are vital to optimal brain function and workout performance, says Alexandra Caspero, R.D., a St. Louis-based dietitian. Cutting them often results in lower levels of essential vitamins, minerals, and fiber found in whole food carb sources. “Stick to a moderate carb intake diet, even when you’re trying to lose weight,” she says.
The Quality vs. Quantity Question
Here’s what often gets lost in the carb debate: it’s not really about how many carbs you eat—it’s about which carbs you eat. There’s a world of difference between a doughnut and a bowl of oatmeal, even though both contain carbohydrates.
Whole food carb sources come packaged with fiber, vitamins, minerals, and other good stuff that helps regulate how quickly those carbs hit your bloodstream. Processed carbs? Not so much. They spike your blood sugar, leave you hungry again in an hour, and don’t offer much nutritional value.
The Fix: Instead of cutting out or drastically reducing your carb intake, focus on swapping out processed carbs like chips, candy, soda, and white grains for whole sources like fruits, vegetables, and whole grains like wheat, quinoa, barley, and oats, Caspero says. This way, any carbs you eat will fuel your body, without spiking your blood sugar and insulin levels, leaving you hungry 30 minutes later, as is common with quicker-digesting refined carbs.
Smart carb choices to keep on your radar:
- Sweet potatoes
- Beans and lentils
- Quinoa
- Brown rice
- Fresh fruit
- Vegetables (yes, they have carbs too!)
Myth #6: Fasted Cardio Burns More Fat
“There’s a popular idea that performing cardio while fasted—usually right when you wake up in the morning before eating—burns more fat. This sounds too good to be true because it is,” says Sam Simpson, C.S.C.S., C.P.T., co-owner and vice president of B-Fit Training Studio in Miami. That’s because fasted cardio is synonymous with being under-fueled, meaning it can drastically reduce your capacity to perform high-intensity exercise. (Even if you feel like you are working hard, we’re willing to bet your mile times will be substantially slower.) While you do burn a greater proportion of calories from fat as compared to carbs when you perform low- to moderate-intensity exercise, you burn fewer overall—oftentimes including the number of calories you burn from fat. It can also contribute to losing muscle mass, which is not at all the kind of weight you want to be losing, since less muscle means a slower metabolism.
The Real-World Impact
You know that feeling when you try to work out on an empty stomach and everything just feels harder? That’s not in your head. Without fuel, your body can’t perform at its best. You might cut your workout short, move slower, or just phone it in because you’re running on empty.
And here’s the part that really matters: if fasted cardio makes you so tired or hungry that you overeat later in the day, any potential benefit goes right out the window. Sustainable weight loss is about the big picture, not quick tricks.
Fix It: Fuel your workouts! If you like to exercise first thing in the morning, try to get at least a small snack in prior to getting your sweat on. The best pre-workout snacks are rich in both carbs and protein, generally containing about three to four times more carbs than protein, Simpson says. Good examples include a banana and peanut butter, whole wheat toast with jelly, or half of a bagel and one egg.
A few more easy pre-workout snack ideas:
- Greek yogurt with berries
- A small smoothie
- Apple slices with almond butter
- A handful of trail mix
- Rice cakes with nut butter
Myth #7: You Have To Cut Calories To Lose Weight
If you’ve never heard of the “calories in, calories out” equation for weight loss, it goes like this: The amount of calories you take in must be less than what you expend in order for you to lose weight. “However, this equation is a bit oversimplified, and ignores the fact that the type and quality of the calories you eat also matter,” says Tori Schmitt, M.S., R.D.N., owner of YES! Nutrition. Plus, all calories being equal, suffering from unhealthy lifestyle factors like excess stress and not getting enough sleep can prevent weight loss—and even result in weight gain.
Beyond the Numbers
Here’s something most calorie-counting apps won’t tell you: your body isn’t a calculator. Two people can eat the exact same number of calories and have completely different results based on factors like:
- Sleep quality: Poor sleep can increase hunger hormones and cravings
- Stress levels: Chronic stress can lead to elevated cortisol, which may promote fat storage—especially around the midsection
- Food quality: 300 calories from vegetables and lean protein will affect your body differently than 300 calories from candy
- Gut health: Your microbiome plays a role in how you absorb and process nutrients
This doesn’t mean calories don’t matter at all—they do. But obsessing over every single number while neglecting sleep, stress management, and overall wellbeing is like trying to drive a car while only looking at the speedometer.
Fix It: Pay attention to more than just calories in versus out. Focus on following a lifestyle that makes you feel healthy—because, in the end, that’s the lifestyle that’s going to be conducive to weight loss, Schmitt says. Prioritize self-care, whether that means going to sleep 30 minutes earlier each night, not taking work home with you every night, or simply moving more throughout the day.
Simple self-care strategies that support weight management:
- Set a consistent bedtime (even on weekends)
- Take short walking breaks throughout your workday
- Practice stress-relief techniques like deep breathing or stretching
- Stay hydrated throughout the day
- Make time for activities you enjoy—not just exercise you think you “should” do
Related: Here’s Exactly What To Do At Night To Have A Great Sleep
The Bottom Line
Weight loss doesn’t have to be complicated, but it does require sorting through a lot of noise to find what actually works. The good news? Once you let go of these myths, you can focus on what really matters: eating a variety of whole foods, moving your body in ways you enjoy, getting enough rest, and taking care of your overall wellbeing. That’s the kind of approach that leads to lasting results—not quick fixes that fizzle out after a few weeks