15 worst diet tips, ever!

Ridiculously bad diet advice you need to ditch.
© Prevention // © Prevention

You know you can't believe everything you read. And still, you haven't eaten an egg yolk since the 90s, and you can't touch a French fry without being saddled with guilt. Oh, and don't even get us started on the whole don't-eat-after-8-PM-or-else mentality. Let's set the record straight once and for all by calling out these 15 worst diet tips—and offering up smart food rules to follow instead.

-- By Stephanie Castillo, Prevention

1 of 17 Person on a scale (Rick Elkins/Getty Images)

Fat makes you fat

Why that's BS: It depends on the type of fats you're eating, says Tricia Psota, RD, a nutritionist based in Washington D.C. "Fats in chips, cookies, and greasy foods can increase cholesterol and your risk for certain diseases. But good fats, like nuts, avocados, and salmon, protect your heart and support your overall health." And when paired with a healthy diet, the right fats can help keep you from being, well, fat, adds Sharon Palmer, RD, author of The Plant-Powered Diet.

Try this: Healthy Fats That Make You Skinny

2 of 17 Nachos (R&R Publications/Getty Images)

Stop snacking to lose weight

Why that's BS: Eating in small, frequent amounts is a great way to curb hunger, control portion sizes, and make better nutritional choices, says Mike Clancy, CDN, a personal trainer at David Barton's Gym in New York City. "Smarter snacks like nuts, fruits, and yogurt will keep your energy levels high throughout the day." 

Do you know that the average person eats 580 calories a day in snacks?Click here for 16 Ways To Curb Mindless Munching. 

3 of 17 Woman eating at a desk (Paul Bradbury/Getty Images)

A calorie is a calorie—and you should count them

Why that's BS: "Not all calories are the same," says Clancy. "The type of calories, the timing of the calories, and the quality of the calories can significantly alter the effect of the calories on the body," he says. "Food creates reactions within our bodies and the type of food you eat is an important component in diets."

For example, 50 calories of an apple will cause a different internal reaction than 50 calories of cheesecake, says Clancy. "The quality of the calories is also important because the chemicals, hormones, and general byproducts that are found within processed food effects the absorption of real nutrients." Quality calories are nutrient dense, like spinach. Calories that don't contain any nutrients—also known as "empty" calories—are like the ones found in French fries.

Bottom line: Calories are important for understanding portion control, but they’re not the only factor in good nutrition, says Clancy. 

Plus: 10 Calorie-Burning Myths, Busted

4 of 17 Woman looking at food (MSW/Getty Images)

Load up on protein

Why that's BS: Sorry, caveman lovers: eating lots of protein is not the key to healthy weight loss. Why? The body needs three macronutrients: Protein, carbohydrates, and fat, says Rania Batayneh, MPH, a nutritionist and author of the forthcoming The One One One Diet (published by Rodale, which also publishes Prevention), and focusing exclusively on protein for weight loss makes no sense. "You not only deprive your body of fiber and other antioxidants found in healthy carbohydrates—whole grains, fruits, and veggies—but you also run the risk of eating too much fat in your diet which can lead to high cholesterol and triglycerides.”

Prepare a protein-filled dinner in no time with these20 Delicious 30-Minute Chicken Recipes.   

5 of 17 Meat (Svariophoto/Getty Images)

You burn more calories working out on an empty stomach

Why that's BS: Working out with or without food in your stomach doesn't affect calorie burn—but skipping meals before sweat sessions may result in muscle loss, finds a study published in the Strength and Conditioning Journal. And before you settle for a sports drink, know this: While a quick sip of sugar energizes your muscles, the drink’s other artificial additives can be harmful to your health, says Sanda Moldovan, DDS, MS, CNS, a diplomat of the American Academy of Periodontology. 

Instead, go for naturally sweet fruit, like bananas, peaches, and mangos before your sweat session. Or try an ounce of dark chocolate for the same caffeine fix you get from a half cup of coffee. "Chocolate also contains feel-good substances, called neurotransmitters, which are the same release during a 'runner's high,' " says Moldovan. 

Munch away on these22 Delicious Guilt-Free Snacks.      

6 of 17 Woman running (Jordan Siemens/Getty Images)

Eat every 2 hours to rev your metabolism

Why that's BS: Going four or five (or even eight!) hours between normally-sized meals will not make your metabolism slow down, says Monica Reinagel, MS, a nutritionist based in Baltimore. "Eating more frequently may help stave off hunger, which can help you fight temptation. But if you want to do this, you have to be careful to keep your meals and snacks really small," she says. "Otherwise, eating every 2 hours can simply lead to taking in too many calories over the course of the day."

You can help your body burn more calories by incorporating these Foods That Speed Up Metabolism into your daily meals.

7 of 17 Celery and peanut butter (George Crudo/Getty Images)

Swear off forbidden foods

Why that's BS: "We tend to be in 'all or nothing' mode when we diet and never seem to find a middle ground," says Batayneh. "You have to realize that you can’t have pizza, French fries, and chocolate cake all in the same day, but—with careful planning—you can enjoy these foods when they are presented to you. Just don’t go for seconds and share if you can." In fact, research shows that moderately indulging in "forbidden foods" is what keeps people from bingeing on the stuff.

While dieting can definitely help you reach your ideal body weight, make sure not to ditch these7 supposedly "forbidden" foods that actually help you lose weight.        

8 of 17 Chocolate (Alexandra Grablewski/Getty Images)

Drink your fruits and veggies

Why that's BS: While shoving five servings of fruits and vegetables into a juicer seems like a simple and efficient way to get the daily recommended amounts, it comes at a cost, says Batayneh. "Unfortunately, juicing fruits and vegetables removes one of their most valuable components: fiber. Found in the pulp, skin and seeds, fiber’s list of benefits ranges from filling you up to maintaining stable blood sugar levels." If you're juicing more sweet stuff (fruit and carrots) than green stuff you're also going to seriously spike your sugar. (Some juicers allow you to keep in the pulp, so that's another option.)

TRY INSTEAD: 6 Drinks That Shrink Your Belly

9 of 17 Smoothie (Andy Richter/Getty Images)

Eat as few calories as possible

Why that's BS: "Ugh, awful tip," says Chrissy Carroll, MPH, RD, founder of Inspired Wellness Solutions, LLC. "When you cut your calories too low, your body acts as if it's going into starvation mode and your metabolism slows down." But a reasonable goal, adds Carroll, is to cut approximately 500 calories each day through diet and exercise, which will lead to a healthy rate of weight loss of one pound per week.

Energize your workout with these 14 Snacks That Power Up Weight Loss

10 of 17 Meat with sauce (Iain Bagwell/Getty Images)