Learning what a portion size actually is and actually eating that amount can be hard. The average person is not good at estimating what one serving looks like.  And they get little help from advertising that too often shows someone happily tucking into a meal that is usually at least more than a single serving.

One study, done by Summa Health System, of 329 overweight people found that 38 percent of the volunteers who used portion control for two years lost 5 percent or more of body weight, compared to the 33 percent of the subjects that didn’t. In fact participants who didn’t use portion control gained at least 5 percent of extra body weight. 

Here are four tips to keep your servings in check and steer clear of mindless overeating:

Avoid skipping meals. When you’re hungry you have a better chance of eating a large portion. Try not to go longer than five hours without eating so that when you do eat you are satiated enough to think about what you’re eating and make an informed decision.

Measure and weigh before you eat. Don’t be afraid to use measuring cups or even a kitchen scale. It’s easy to overestimate a serving; before you know it you could have consumed double the recommended portion and calories.

Know the rules. There are standard rules for deciding how much one serving is. When in doubt, a three ounce serving of lean meat is usually the size of a deck of cards and the average fist is close to the equivalent of one cup of breakfast cereal.

Use portion-control plates. Reminiscent of toddler plates with the separate sections for each dish, these plates help you decide how much of each dish is a recommended serving.  A study conducted at the University of Calgary found that 130 people who used these plates lost at least 5 percent of their body weight.

(Photo: Oil Scarff/ Getty)