Experts have recently proved that a key factor that may lead in many cases to obesity in the fact that people are used to eat as much as they are given. For instance, if one goes to the restaurant, orders a meal and the plate is overloaded with food, he will consider it "just a meal like any other" and will eat it all. If one buys a soda can that is double the size of a regular one, again he will consider it "just a soda can" and will drink it all. In consequence, people do not take into account anymore the specific amount of one item of food or drink, but the fact that it is "an item" - a bottle, a can, a glass, a plateful etc. - nothing more.

"Whatever size a banana is, that's what you eat, a small banana or a big banana. And whatever's served on your plate, it just seems locked in our heads: that's a meal," says Andrew Geier who led the study and the research team at the University of Pennsylvania.

Therefore, this is where lie most of our chances to get overweight - some of us frequently forget that we have to take into account the quantity of food, not the item. This is explained by the experts as a tendency towards "unit bias." It is completely wrong to see things this way, however, because we should not forget that most of the diets have strict amounts of foods recommended - 100 gr of meat, 200 gr of yogurt and so on.

And this is why people that are on diets use smaller plates, forks or spoons and even cut the food in smaller portions - in order to reduce meals they eat and to auto-suggest themselves into believing that they eat more than they actually do. As a counterexample, overweight people tend to use larger plates and fill them with more food, but their consciousness is clear, because they only eat a meal.

The misconception that we eat only one meal, only one item of food would not be that bad if all food would be canned in smaller rations, of 100 or 200 gr, or depending on calories - one can to contain 100, 200 calories. The weight gain could also be prevented if restaurants and fast foods would not serve so overloaded plates.

This fact led the researchers to investigate and compare, for example, canned foods in US and in France. They noticed that yogurts in US are almost twice as big as yogurts in France. However, this does not mean that French people eat a double amount of yogurt from the supermarket in order to supplement the smaller quantities. The conclusion of the researchers was that obesity and related disorders are mostly caused by the surroundings that have a bad influence on the amounts of food people eat.

This is where the whole idea of the study came from. The researchers took simple tests to see how the size of eating tools impinges upon people. For instance, they put a large bowl filled with one pound of M&M's candies in the lobby of an apartment building with a sign above: "Eat Your Fill ... please use the spoon to serve yourself." The "tricky" element in the experiment was the spoon. Some days researchers put a big spoon in the candy bowl and some days a small spoon. This is how they reached the conclusion that people ate more candies in the days when the big spoon was used by people to serve themselves.

Dr. Andrew Geier and colleagues believe that reducing amounts of food and drink that people buy from supermarkets and also reducing the quantity of food in a meal eaten at the restaurant or fast food would considerably help people against weight gaining.