Losing weight is really just about math -- the calories you take in need to be a bit less than the calories you burn. And while most good dieters know to check the labels on the foods they eat to make sure they are waistline-friendly, new research suggests that those labels may actually be deceiving you. In fact, they could be off by as much as 25 percent.

In some cases, this is good news. Nutrition experts in Britain are adamant that most nutrition labels over-estimate the number of calories in certain foods because the methods used to determine the caloric content are outdated. If foods were subjected to more recent and innovative form of analysis, the numbers would be more accurate they argue, and in most cases that figure would be less than previously advertised. For instance, a vegetarian lasagna, which is claims to have 400 calories, may actually only have 367 calories, a difference of 33 calories.

But other research has found that when it comes to restaurant meals, the difference between the advertised nutritional value and the actual calorie count usually isn't in our favour. Studies from Tufts University in the States found that people dining out were often treated to 18 percent more calories than they thought they were consuming. For a 500-calorie meal, that can add nearly 100 extra calories to your hips. That might not seem like much, but it can add up fast.

And then there's this interesting fact to consider: A recent study of dieters found that those who overestimated the calorie counts in the foods they ate were more likely to lose weight than those who didn't. Maybe it's best to just ignore the labels and aim high when you're guessing the calorie content of your lunch?

If there's a message here, it's this: Use those nutrition labels as a general guide, but don't take them as gospel. The only way to really know the nutritional value of your food is by making it yourself using wholesome ingredients that you know are good for you.