The 7 Worst Dieting Tips Registered Dietitians Have Ever Heard

Everyone has a diet tip to share. How many times have you been told you must do this or that or the other thing to lose weight? The tips often sound too good to be true, while also being good enough to leave you wondering if you should give it a try. The confusion and sheer amount of conflicting information out there is to blame for people falling for fad diets or feeling frustrated with a lack of results despite seemingly eating "better."

As registered dietitians, we hear all sorts of tips and tricks for losing weight—some not-so-good, others just downright dangerous.  In an effort to help those struggling with their weight learn how to approach healthy, sustainable eating, I asked dietitians from around the country the worst diet tips they ever heard and their answers might come as a shock.

Terrible Diet Tip #1: Eat fruit only for breakfast.

According to Lauren Harris-Pincus, M.S., R.D.N., founder of and author of "The Protein-Packed Breakfast Club", eating a fruit-only breakfast isn't smart because "fruit contains only carbohydrates, which means it will be digested and absorbed quickly, leaving you starving an hour later." Plus, Harris-Pincus says that you're missing out on other key nutrients that will help you in the long run. "Consuming protein at breakfast is important to help prevent muscle loss as we age," she says.

Instead: Include a balance of protein, fiber and healthy fats at breakfast to keep your energy levels up all morning. Enjoy your preferred fruit with eggs and oatmeal or Greek yogurt with nuts or seeds.

Terrible Diet Tip #2: Avoid fruit because it's too high in sugar.

On the other end of the spectrum, some mistakenly believe they must avoid fruit altogether if they want to lose weight. Registered dietitian nutritionist, Malina Malkani, M.S., a media spokesperson for the Academy of Nutrition and Dietetics and creator of the Wholitarian™ Lifestyle says, "Sugar gets a bad rap because of the presence of added sugars in processed foods. It's easy to get confused because fruit does contain sugar."

Registered dietitian, author and spokesperson Manuel Villacorta, M.S., explains that only one in 10 Americans are meeting their daily fruit recommendations, and fears that misconceptions about sugar could actually be harming our health. "[I saw a social media post recently that] went so far as to compare the sugar in fruit to the sugar in a Snickers bar," he says. "Fruit delivers natural sugars along with antioxidants, while a Snickers bar has little nutritive value."  

Malkani explains that there are key differences between the natural sugars found in whole fruits and the refined sugars added to processed foods to increase palatability and shelf life. Among its many benefits, fruit also contains fiber, which helps slow the absorption of fructose, the main type of sugar found in fruit, into your bloodstream. The fiber in fruit also helps us feel fuller longer, which in turn, helps us eat fewer calories and better manage our weight. Lastly, the fiber in fruit contributes to the good bacteria in our intestines, which in turn contributes to better gut health.

Instead: A good rule is to "eat the rainbow" and choose a wide variety of different colored fruits that are packed with nutrients, fiber and antioxidants. With no added or refined sugar, it's difficult to overeat fruit to the point of sabotaging your weight-loss goals.

Terrible Diet Tip #3: Only shop the periphery of the grocery store.  

Dr. Joan Salge Blake, a nutrition professor at Boston University and host of the health and wellness podcast Spot On! debunks this common diet tip by explaining, "The bakery is on the periphery of the supermarket, [for one, while] all the fabulous, nutrient-rich foods such as whole grains, frozen fruits and veggies, fiber-packed canned beans are smack in the middle of the store."

Instead: Don't be afraid to get in those aisles! Use your best judgement and skip aisles that might tempt you to impulse buy treats, but you can and should utilize the entire store—it's good exercise, too!

Terrible Diet Tip #4: Eat a very-low-carbohydrate diet to lose weight.

"There's no evidence that a diet low in carbohydrates is any better for weight loss than a diet low in fat, and low-carb could be bad for health in the long run," according to Elizabeth Ward, M.S., R.D. of Better Is the New Perfect. A low-carb eating plan starves the beneficial bacteria that live in your gut, as it's very difficult to get enough fiber on a low carb diet. Fiber feeds gut bacteria, which play a role in supporting health and preventing some chronic conditions. Plus, if exercise is a part of your weight-loss plan, your body needs carbohydrates to generate enough energy to power you through those workouts.

Instead: Ward recommends including whole grains, legumes, vegetables and fruit as part of a balanced diet every day to get the fiber and carbohydrate you need to function properly.

Terrible Diet Tip #5: You must follow the HCG diet to lose weight.

The HCG diet promotes eating just 500 to 800 calories a day and a daily dose of the hormone human chorionic gonadotropin (HCG) for weight loss. Jim White R.D., an ACSM-certified fitness instructor and owner of Jim White Fitness & Nutrition Studios says, "When you follow a diet under 1,200 calories you are not getting enough nutrients to sustain health, exercise and vitality." Even the FDA warns consumers about this diet and eating so few calories per day. White warns that the diet can be very dangerous and might leave you feeling malnourished, hypoglycemic and weak when followed for an extended period of time.

Instead: Skip the trendy diets altogether and aim for sustainable healthy eating habits. White recommends following a balanced diet that offers a variety of foods, including fruits, vegetables, whole grains, lean meats, healthy fats and low-fat dairy.  

Terrible Diet Tip #6: Follow the keto diet to lose weight

Sharon Palmer, R.D.N., "The Plant-Powered Dietitian", says the reason this is the worst diet tip lies in how complicated it is to accomplish correctly. "To get your fat content that high and your carb content that low means that you can't eat a normal diet in any way; you really can't go out to eat and enjoy social occasions with your friends and family."

Plus, it's not a healthful diet for the long-term. In order to get that low in carbs, you have to eliminate most plant foods, such as whole grains, pulses (beans, lentils, peas), soy foods, fruits and many vegetables. "We know these are extremely important foods for a long, healthful life," Palmer explains.  "These foods are filled with fiber that feeds the gut microbiota, and phytochemicals that provide antioxidants and anti-inflammatory compounds."

Instead: If you're looking to change up the way you look at food, consider trying a plant-based diet with mostly whole, minimally processed plant foods, eat reasonable portions and limit added sugar.

Terrible Diet Tip #7: Do not eat after 8 p.m.

Think about the last time you ate late at night. Chances are the foods you were eating were higher in fat, possibly fried or eaten mindlessly while multitasking. Much of the thinking behind this rule comes from the quality and quantity of food that people eat at later hours, not the hour itself.

Alissa Rumsey M.S., R.D., owner of Alissa Rumsey Nutrition and Wellness, says abiding by this rule no matter the circumstances can also affect your shut-eye. "Going to bed hungry will inevitably disrupt sleep quality," she explains. "This not only negatively impacts overall energy levels, immune health, and muscle mass, but may also lead to overcompensating, or overeating, in the morning."  Hunger is a natural, biological motive signaling the need to take in calories for survival. The body treats all calories the same, regardless of the time of day, so if you haven't eaten in a few hours and feel your tummy grumbling, opt for a light meal without feeling guilty.

Instead: "Since daily schedules may vary, it's less important to think about the time of day you are eating and more important to pay attention to your hunger signals," Rumsey recommends. Eating a well-balanced meal for dinner, one which includes carbohydrates, protein and fat, will ensure longer satiety and satisfaction no matter what time you eat it. Similarly, if you are hungry later at night you should honor that hunger and eat something. This will ensure that your sleep isn't interrupted by hunger and that you won't be starving come morning.

Ultimately, healthy eating comes down to eating well and balanced most of the time. It's not the easy answer, nor is it the most clear, which is why fad diets and dieting rules with simple instructions are often a weight-loss warriors first stop along their journey. However, if you can learn to honor your hunger, control your temptations most of the time and eat a range of nutrients, your body will slowly adapt as you lose weight and become a healthier, happier you.