There are some mindsets that can derail even the best weight-loss intentions. And while making over your body is a great goal, it's possible that to reach it, you also need a mental makeover - at least where your attitudes and beliefs about dieting are concerned.

Here are some commonly held beliefs about dieting, why they can lower your chances of success, and how to beat each obstacle.

Trap #1: Dieting has to be all or nothing.

The truth: It may feel virtuous to turn down chocolate cake, french fries, and every other treat that crosses your path, but in time, the temptation is likely to wear you down. And if you've been deprived of treats for a long time, you're all the more likely to load them on when you do cave in.

The fix: Make sure you indulge in the occasional treat. But make sure it's in moderation and only splurge on foods you really love.

Trap #2: Once you fall off the wagon, there's no point in getting back on.

The truth: The road to weight loss isn't always smooth, and you are bound to encounter some pitfalls along the way. Whether you've gone on vacation or just had a heavy restaurant meal, going off the plan can make you feel like you've blown your whole diet. But you've really only blown it if you decide to give up altogether rather than resume your healthy eating habits at your next meal.

The fix: Pick yourself up and get right back on the plan. It's normal to feel disappointed in yourself if you slip up. But in the long run, one little slip-up doesn't make a difference if you get right back on the plan. Don't wait until tomorrow or after the weekend - do it at your next meal.

Trap #3: A serving is the amount of food you can fit in your bowl.

The truth: The calories listed on the package are the amount contained in a specific amount of food, and that's not necessarily the amount you're eating. For example, your cereal may have 120 calories in a one-cup serving. But if your bowl holds 2 cups of cereal and you fill it right up, you're actually getting 240 calories. And extra calories from oversized portions add up!

The fix: Familiarize yourself with how big your portions should be, from a 3-ounce chicken breast that's about the size of a deck of cards to a half-cup serving of pasta that's the size of an ice-cream scooper. To start, weigh or measure out portions until you start to get a good idea of what different amounts look like.

Trap #4: Food doesn't count if it's fat-free.

The truth: While this belief was popularized with the invasion of fat-free products in the 1990s, it couldn't be further from the truth. The amount of weight you gain or lose is determined by the number of calories you eat compared to the number you burn. Still, few of your calories should come from fat. Instead, focus on getting your calories from foods that will fill you up and help you gain muscle.

The fix: If you're trying to lose weight, keep an eye on your overall caloric intake, and try to get your energy from foods rich in fibre, protein, and other important nutrients.

Trap #5: Nighttime snacking turns directly into fat.

The truth: Food you eat after dinner doesn't automatically land on your thighs, but if you've already had your fill of calories for the day, the extra snack could get the scales tipping in the wrong direction. But it's the extra calories that cause the problem, not the timing.

The fix: If you really enjoy a bedtime snack, then budget for the extra calories after dinner. But if you find you are getting hungry despite already having had your fill, consider adding a bowl of soup or some salad to your dinner, or swapping pasta or bread products for the whole-wheat version to help you fill up.

Trap #6: It's best to stick to the same foods.

The truth: When you're dieting, it can be easy to get stuck in a rut. Maybe you've settled on a meal that exactly fits your caloric needs so you find yourself eating it again and again or you're afraid to veer outside of a select group of diet-friendly foods. But if you're bored with your meals, you're more likely to cave when temptation comes along.

The fix: Diet food doesn't have to be boring. Focus on high-quality ingredients, which tend to have more flavour, and really try to mix it up. Adding fresh herbs, balsamic vinegar, or even a small amount of good-quality olive oil or parmesan cheese to your meal can help keep things interesting without adding too many calories.

Written and reviewed by the MediResource Clinical Team