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20 Things Dietitians Say You Should Never Do

There are some things people do in an attempt to be healthier that nutritionists strongly urge against.

Most people work with registered dietitians to find out more about what they should be doing to lose weight and improve their physical health. But—newsflash!—getting healthy is often just as much about what not to do as it is about what to do. In some cases, listening to the wrong sources, falling for misleading marketing ploys, and believing that some foods are just plain evil can do more damage to your overall health than doing nothing at all.

We asked five dietitians about the weight loss and faux "health" strategies they never, ever recommend to their clients. (In other words, exactly which popular trends they would be perfectly happy to see drop off the face of the earth forever).

Here are the 20 things dietitians said you should never do. And as for what you should do, don't miss these 40 Tips Nutritionists Say You Must Follow to Lose Weight, and be sure you're stocked up on The 7 Healthiest Foods to Eat Right Now.

Restricting way too many calories

Woman not eating enough

To lose weight, you'll probably have to cut back on calories, but weight loss it's not always a "less is more" equation. Following a very low-calorie diet (like under 1,000 calories per day) can do more harm than good.

When you don't eat enough, "you set yourself up for extreme hunger and deprivation, which can lead to binges and regaining the weight you lost," says New Jersey-based dietitian Erin Palinski-Wade, author of Belly Fat Diet For Dummies. "Repeated attempts at very low-calorie diets over time can also slow your metabolism."

Avoiding gluten (unless you're allergic to it)

gluten free bread

If you have diagnosed celiac disease or non-celiac gluten intolerance (or think you might), consuming gluten could not only cause GI distress but many other systemic side effects. But eliminating gluten just because it's trendy or you think it might help you lose weight? Not recommended. In addition to eliminating healthy foods, like whole grains, you could be introducing unhealthy ones.

"If you reach for a lot of processed 'gluten-free' foods you may find yourself gaining weight since many of these foods use gluten-free refined grains like white rice, which remove the fiber and protein from the food," says Palinski-Wade, who adds that these types of foods can leave you less satisfied and prone to eating larger portions.

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Going on a juice cleanse

apple juice

Add this one to the list of diets that experts absolutely hate. Similar to the fake news about "detox" diets, there's a lot of talk about how going on a juice cleanse can clear excess waste from your system and help you lose weight fast. The only problem is it's all baloney.

"Even if the juice is pressed from fruits and vegetables, you've basically extracted the vitamins and minerals, along with a bunch of sugar and none of the fiber—that doesn't cleanse your body," says Lainey Younkin, MS, RD, weight loss dietitian at Lainey Younkin Nutrition, who recommends choosing smoothies with plenty of fiber, protein, and good fats.

Obsessing over the scale

Frowning woman standing on scale

We have a new five-word mantra for you: step away from the scale. It's not a reliable, productive, or motivational metric for determining your health, and counting on it to give you a comprehensive picture of your weight loss progress can set you up for failure.

"The number on the scale is the sum of your muscle, fat, bone, water, and everything inside your body, not a measurement of [fat alone]," says Younkin. "If you're trying to lose weight, use the scale as a tool—but not your only tool."

Buying into the superfood hype

Goji berries

While there are definitely some foods that are more nutrient-dense and health-promoting than others, the best way to increase the nutritional benefit of your meals is to eat a variety of colorful plant-based foods (you want a rainbow on that plate, people!).

"True wellness includes a balance of foods that are jam-packed with nutrients and foods that are pure pleasure," says registered dietitian Barbie Boules, RDN, CHC of Barbie Boules Longevity Nutrition, Inc. "There is nothing magical about any particular food so you can skip the goji berries and maca."

Thinking 'low weight' equals 'healthy'

scale weight loss

If you're waiting until you hit a certain weight to feel good about yourself, remember that "skinny" doesn't always mean healthy…and your weight doesn't determine your value.

"Weight is an indicator of your relationship with gravity," says Lauren Harris-Pincus, MS, RDN, founder of and author of The Protein-Packed Breakfast Club. "There are so many more important things to focus on regarding health and well-being than the number on the scale."

Trying to 'detox' your system

cruciferous vegetables capsules, dietary supplements

Thinking about popping a supplement or forking over cash for a "detox" tea to rid your body of unnecessary waste? Don't bother, says Boules.

"This concept is complete nonsense and typically way more expensive than [eating] truly nourishing food," she explains. "Your liver, kidneys, and digestive system rid your system of waste 24/7…if those organs aren't running right, [this stuff] isn't going to fix it."

Being afraid of carbs

whole grains pasta cereal bread

Carbs are evil, right? We should never eat carbs again, right? Yeah, no. Living in fear of carbs means you'll be giving up on lots of 100% healthy foods that have carbs, like fruits and vegetables.

"Instead of being scared of all carbs, choose whole grains and high-fiber carbohydrates most of the time to stay full, curb cravings, maintain your weight, and keep blood sugar stable," says Younkin.

Falling for the false promises of crash diets

rice cakes

When you've tried losing weight by eating less and exercising more, it's natural to wonder if the latest diet craze—which gloats about its track record of astronomical weight losses—is the smart way to go. Spoiler: it's not.

"Restrictive or rapid weight loss diets [often] promote orthorexic behavior and advocate food fear by making erroneous claims about perfectly healthy foods," asserts Boules, who says that any approach to eating that you can't maintain for the rest of your life is not worth starting in the first place.

Drinking your vegetables

Green smoothie

Sorry, V8 lovers: while a green juice every once in a while can be a healthy way to stay hydrated and increase your vitamin intake, you shouldn't replace liquid veggies for the real deal.

"Juice, even from vegetables, is relatively high in sugar without any of the fiber [that] slows down digestion and allows you to fully absorb all of the nutrients," says registered dietitian Danielle Schaub, RD, senior manager of nutrition and culinary products for Territory Foods.

Having a cheat day

woman eating dessert

When you're following a strict diet, you might think you're doing yourself a favor by indulging in a cheat day, but that's actually not a beneficial mindset. Younkin says it implies that you're doing something wrong and encourages a dieting mentality counterproductive to long-term success.

So what should you do instead? "Have an 80/20 mindset where 80% of the time you fill your plate with fruits, vegetables, whole grains, protein, and healthy fat, and 20% of the time you indulge in dessert and wine without any guilt," suggests Younkin.

Wallowing in guilt about your food choices

guilty diet

When food becomes tied to feelings of guilt and shame, it's nothing but a recipe for misery (and, often, disordered eating habits).

"Thinking 'I've blown it anyway, so I may as well have more fries,' doesn't help and only causes more harm," says Harris-Pincus. Food should make you feel good, not guilty.

Cutting out whole food groups

paleo vegetable variety

The diet world is full of people claiming that if you just cut out this one food group (or, frighteningly, several food groups…looking at you, paleo diet) then you will be able to shed pounds and live your best life. However, this remains one of the worst approaches to sustainable weight loss.

"Fad diets [that eliminate entire food groups] are tempting but do not result in permanent weight loss or positive lifestyle changes, both physically and mentally," warns Harris-Pincus. "There are wonderfully nutritious foods in all food groups to enjoy."

Using supplements excessively


If you have more supplements than you have pairs of shoes in your house, it might be time to reconsider what they're all doing for you—and whether they were manufactured from a trustworthy source.

"Supplements like vitamins, herbs, and protein powders are not regulated [by the FDA] so you don't know what you're buying and have no clue about efficacy," warns Boules. She only recommends supplements when her clients have a diagnosed deficiency or it's clear that their diets are lacking certain vitamins or minerals.

Following a low-fat diet

low-fat diet

We know a lot more now than we used to about the role that fats—the bad kinds and the good kinds—play in our diet. Avoiding all fats because you think they will make you gain weight means you'll be missing out on some good fats full of beneficial nutrients.

"Unsaturated, plant-based fats such as avocado, nuts, and olive oil are associated with numerous health benefits, like lower cholesterol levels and reduced inflammation in the body," explains Palinski-Wade. "These foods can also help you feel more satisfied, resulting in smaller portions and fewer cravings throughout the rest of the day."

Believing everything you read

label supermarket

You need to bring your critical thinking skills to the grocery store with you these days: just because a food is labeled as keto (or paleo, or low-sugar, or organic, or whatever) that doesn't mean it's good for you.

"Always check the ingredient list and choose things that have more whole foods listed than words you can't pronounce," advises Schaub.

Confusing low-carb with keto

Keto diet foods

There may be benefits to some low-carb diets, but deciding to cut back on carbs and following a keto diet is not the same thing.

"Keto is a very specific, medically-based diet where 70% of your calories must come from fat, no more than 20% from protein, and only 10% from carbs," says Schaub. "If it's not done carefully, you will fail to reach the ketogenic fat-burning state while also missing out on entire categories of foods that are high in essential nutrients and fiber." If you're considering starting the keto diet, you'll first want to know real safety risks and rewards of the ultra-low-carb keto diet.

Forgetting to count the calories in your cocktails

margarita frozen cocktail

You can order as many salads for dinner at girls night as you want, but if you're downing mudslides and cocktails mixed with sugary juice or soda, you're overlooking a major source of calories that can add up quickly, says Schaub.

"Alcohol has almost the same amount of calories as fat," Schaub says, "and alcohol calories are also empty, meaning they provide no nutrients." (FYI: Fat contains about nine calories per gram, while alcohol has seven.)

Blaming one food for 'making you fat'

pasta salad

Have you turned pasta into the enemy when it comes to weight loss? It's time to stop! While there is a nutritional difference between eating a serving of pasta and a serving of kale, for example, Schaub says weight loss is really just about physics. Your body doesn't know the difference between the calories eaten from one food versus another.

"Calories are energy and if energy intake is greater than energy output, you store it; if energy out is greater than energy in, you burn it," she explains. So if you were wondering whether pasta is really unhealthy for you, you now know the truth.

Overlooking the big picture

healthy plate

Ditch the crash diets and cleanses in favor of eating well all the time…but also don't forget to enjoy yourself, guilt-free, once in a while. Maintaining your health is a life-long marathon, not a sprint.

"Optimal health is made up of everyday choices, not a week of super smoothies," says Boules. "If today is indulgent, enjoy it, and just return to nutrient-dense foods and plenty of water tomorrow." One week of smoothies won't do anything to impact your long-term health, but drinking a weight loss smoothie regularly can.

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