Breaking news: You're probably underestimating the number of calories you eat.

Not surprised? Me either. Considering how much portions have grown in the last 20 years, it's no wonder we have trouble eyeballing our meals.

The survey of data from 10,000 people, and 200 doctors, discovered most doctors believe people aren't realistic about the number of calories they are eating.

More results from the survey include:

  • 92 percent of people fail at dieting, and almost 1 in 5 end up gaining more weight than they lost.
  • Only 1 in 3 people use exercise as a means to lose weight.
  • Fewer than 1 in 4 read food labels when grocery shopping.
  • Two thirds of people regard overeating as an addiction.

And finally, 91 percent of people never weigh or measure their food. I can relate to this. When I first started counting calories in earnest, I discovered what I'd been calling two tablespoons of peanut butter to smear on an apple was really four. That's a 200 calorie difference!

Measuring food can be tedious, but it is important. Here's a simple guide that can help you accurately eyeball your portion sizes:

  • One serving of meat is about the size of your palm.
  • A woman's fist is roughly the size of a serving of fruits or vegetables.
  • A serving of nuts should be no bigger than a golf ball, while a serving of peanut butter should be no bigger than the tip of your thumb.
  • Eating cheese? Keep it to six dice-sized cubes.

Measuring your food even for a few weeks can help you learn what a serving size actually is, so that going forward you can estimate a little more accurately.

What's your favorite trick for keeping portions in control?