1. There’s no plan to keep weight off for the long run.
If a diet lasts only a preset number of days, or until you reach your weight loss goal, “you’re not learning behaviors to help maintain that loss,” says Lindsay Martin, RD, dietitian at Hilton Head Health, a weight loss spa in Hilton Head Island, SC.
Since most people who diet gain their weight back within 5 years, “you need a plan that helps you create realistic meal plans and practice mindful eating,” Martin says.
2. You’re allowed only a few foods.
Eating the same few items over and over isn’t just boring. It also doesn't give your body what it needs
“If a diet rules out obvious components of a healthy regimen, like protein sources, fruits, or vegetables, stay away,” says Kristen Smith, RD, a dietitian for the WellStar Comprehensive Bariatric Services in Atlanta. “Well-balanced eating should be key.”
3. You’re promised weight loss from a specific part of your body.
“It’s medically impossible to lose weight from only one part of your body,” says Marjorie Nolan Cohn, RD, a spokeswoman for the Academy of Nutrition and Dietetics.
She explains that you lose fat "throughout the body."
If you want to focus on a particular part of your body, your best choice is a sensible diet plus exercise that includes resistance and strength training.
4. You’re guaranteed to lose X pounds in X days.
Losing weight faster than 2 pounds a week has a downside. “Our bodies are designed to store fat for future use,” Cohn says. Losing too much weight too quickly can mean losing muscle mass. That can leave you “weak and with a slower metabolism, making it even more difficult to keep off weight," Cohn says.
Reset your expectations for how much weight you'll lose, so that you keep it off for good.