One of my best friends, a long time ago, told me that the key to food portion sizes was this: "Eat from small plates, drink from taller glasses." It's a piece of advice I had forgotten, especially after moving to the U.S. where portion sizes seem to have gone from the sublime to the ridiculous. But in a book I'm currently reading called "Mindless Eating" this advice about container sizes is validated by Dr. Brian Wansink, Ph.D, a man who clearly knows his stuff. And optical illusions are at the root of it all. (See also: The Psychology of Salaries: Do You Want to Know How Much Your Coworkers Make?)

I think back to my childhood, to one of the first really cool tricks I was shown by a teacher. A physics teacher actually, but it could have been a math teacher or a chemist. Anyway, the illusion is shown below, crudely illustrated by myself.

Take a look at Lincoln's Stovepipe hat. Is it longer than it is wide?

As you already know this is an optical illusion, then you already know the answer is a trick. The width and the height are identical. Now, replace that top hat with two glasses, one a tall thin glass and one short and fat. Here we have the issue of serving sizes when it comes to anything from juice to alcohol.

Even seasoned bar staff have way more trouble pouring an accurate drink into a short glass than they do a tall one. Usually, they pour more into the short, fat glass. And this is a big problem when trying to pour yourself one serving of orange juice, milk or anything else. If you use the short glass you are always going to overpour, leading to larger portions, weight gain and, of course, less time between grocery trips. Now consider the next optical illusion.

Which white circle is larger? The left or the right?

Once again, it's all just a matter of perception. The circles are in fact identical in size. BUT, they look different due to their surroundings. The circle on the right is dwarfed by the large black circles, the one on the left overpowers them.

This, when applied to food and plate sizes, is perhaps the most important change you can make to you home life. Serve your food on beautiful large plates and you will naturally serve yourself more of everything. Our animal brain wants to fill the plate, and we were always told to finish what was on our plates as children. But on a smaller plate, less food will fill it. Here's a quick example.

Both food portions are identical in size. In studies Dr. Wansink performed, people ate what was in front of them and if it looked like more, they felt more full. In fact, one study involved a burger that was simply flattened out and placed inside a larger bun. Because it looked like a larger burger, the people in the study felt more satisfied.

Now, if you are using the larger plates at home, chances are you're over-serving yourself on a nightly basis. That again means more calories per meal and more food to buy more often. It's not good for you, it's certainly not good for your wallet. And it can all be avoided by simply getting smaller plates (which to be honest are harder to find, but worth the effort. Dinner plates have significantly increased in size since the 1950's, no doubt to accommodate our growing demand for more food).

There's an old saying in cuisine..."the first bite is with the eye."

I believe this to be true on many levels, and not just one of taste perception. If we see a bigger meal, we'll feel more full. If we see a big plate with a small amount of food, we're already thinking "hmmm, that's not going to be enough." It's also worth noting that these days, time plays a big factor in our eating habits. Like the French, we all need to slow down and enjoy our food. Take longer, smaller mouthfuls. And above all, we need to let our bodies tell us when we are full, not signals like an empty plate or glass.

As a Wise Bread reader, you're already smart about where you shop for your food. You also need to be smart about how you eat it. Smaller portions are better for your waistline and your wallet. Don't get fooled by optical illusions.

You can find a copy of Dr. Wansink's excellent book at Amazon (grab the paperback, it's cheaper.) I haven't even scratched the surface of the stories he tells about our mindless eating habits. An eye-opening read and well worth your time.

Mindless Eating: Why We Eat More Than We Think