Have you stopped and looked at the label of foods you are eating - I mean really looked? Do you know how many calories are in the fruit you are eating - and if so have you paid attention to the size of the fruit or the ounces/pounds etc.
An apple - something simple don't really think about. Did you know that an apple has as much as 110 calories? Is it a big deal that an apple has that many calories? Next to the serving size you can see the size. Apples come in all shapes and sizes - when calculating your calories this needs to be taken into consideration. This is an easy label - 1 serving is 1 apple. Check out the next...
The above is for a cup of pasta. This is straight pasta (obviously different types will have different amounts) without any sauce. 1 cup of pasta - 180 calories. Have you actually measured how much pasta you are putting on your plate? 1 cup of pasta really isn't that much. So, two cups? 360 calories. For the above female that is 25% of her total calories for the day! This is just a small insight in how food labels can be your best friend when used right but your enemy if used wrong.
So many people (myself included), have looked at food labels and said to themselves, oh it's only 70 calories. Yup it's 70 calories for approx. 15 M&Ms but the whole bag? 261 calories. The label gives the calories in an X amount - make sure the X amount is what you are calculating.
I was going to do a whole thing on reading food labels but decided that just giving a link to a website that has done all the explaining is easier and more informative than I could do. So, for more information on food labels and how to read them go here
http://www.acaloriecounter.com/food-labels.php for US residents.
For British labels,
http://www.bhf.org.uk/heart-health/prevention/healthy-eating/food-labels.aspx and/or http://www.britishnutrition.org.uk/home.asp?siteId=43§ionId=432&subSectionId=323&parentSection=299&which=1
Oh and btw to work out how many calories you need to consume to maintain a specific weight follow one of these formulas:
Women: 655 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
Men: 66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age in years)