Throughout our years of practice, registered dietitians have heard bad nutrition advice that just makes us shake our heads. From misinformation on social media to over-the-top recommendations, we’ve pretty much heard it all.

We asked dietitians nationwide the worst pieces of advice they’ve heard over and over again. Here, you’ll find terrible nutrition “advice” that you just shouldn’t follow and why.

“This advice oversimplifies hunger and can backfire,” says Drew Hemler, MSc, RD, CDN, FAND, health education specialist. Hydration is important, and yes, a big glass of water can create a temporary sense of fullness. However, water doesn’t provide the nutrients and energy (a.k.a. calories) your body needs to function well. “An analysis of U.S. adults found that while skipping meals did cut calories, it also led to poorer diet quality – lower intakes of fruits, vegetables, whole grains, dairy and plant proteins,” he explains.

Instead, Hemler recommends swapping out sugary drinks for water. Doing so not only cuts excess calories, but research shows it can help with long-term weight management. A 2024 review found that replacing sugar-sweetened beverages with water or other no-calorie options led to a sustainable body mass index (BMI) reduction. “These findings underscore a simple truth,” says Hemler. “A balanced meal plus smart beverage swaps support sustainable weight loss far better than trying to silence hunger with water alone.”

“This approach grants unrestricted permission to indulge, typically for an entire day, as a break from an otherwise ‘clean eating’ regimen,” says Jamie Mok, MS, RD, national media spokesperson for the Academy of Nutrition and Dietetics and owner of Yogini RD LLC. Mok explains that the problem with recommending cheat days is that it’s unhelpful advice that does not teach balanced eating habits or how to practice moderation. Allowing cheat days most likely indicates an overly restrictive diet that is unenjoyable, and therefore, unsustainable. These diets tend to fail those seeking long-term results. In addition, “Overly restrictive diets tend to increase our desire for forbidden foods, which can lead to overeating, binging and yo-yo dieting — all of which not only hinder progress but also damage our relationship with food,” says Mok.

Instead, Mok recommends building lasting, healthy eating habits by adopting a flexible eating approach that emphasizes a variety of nutrient-dense foods while leaving space for foods that simply bring joy.

This is the worst piece of nutrition advice often heard by Patricia Bannan, MS, RDN, author of From Burnout to Balance and founder of Wellness Intelligence™ who says that “unless you have a medical reason (like celiac disease, gluten sensitivity or lactose intolerance) or follow a vegan lifestyle, there’s no need to cut out these foods.” Bannan explains that whole grains with gluten can provide fiber, B-vitamins and minerals, while milk and dairy offer high-quality protein, calcium, vitamin D, potassium, iodine and more. Plus, there are convenient lactose-free dairy options for those who need them. Eliminating these foods unnecessarily can make it harder to get certain nutrients, and it can take the joy and ease out of eating. The key is focusing on balance and variety rather than unnecessary restriction.

Malina Malkani, MS, RDN, CDN, child feeding expert, owner of Malina Malkani Nutrition and author of Safe and Simple Food Allergy Prevention says this is the worst piece of nutrition advice that she hears far too often. “As a registered dietitian, this makes me cringe, because it unfairly puts one of the most nutrient-dense, health-promoting food groups on the ‘do not eat’ list,” says Malkani. Fruit does contain natural sugar, but it’s packaged together with fiber, water, vitamins, minerals and powerful antioxidants that support gut health, heart health and even lower the risk of chronic disease.

Rather, you should aim to minimize added sugar, which is often found in higher-calorie, lower-nutrient foods. “Instead of avoiding fruit, a smarter strategy for long-term health and wellness is to consume a colorful variety of about 1.5 to 2 cups of fruit per day as recommended by the Dietary Guidelines for Americans.”