Proteins, carbohydrates, fruits and vegetables. Some are good for us, some not so good. How do you choose?
Harvard's Dr. Walter Willett has come up with an idea that turns the government's food pyramid upside down.
Under the old pyramid, you were supposed to eat six to 11 servings a day of carbohydrates. The new pyramid reduces that to two to three servings, and limits the carbs to whole grains.
As for fat, the old pyramid says eat it sparingly. But the new one says fat is okay, provided it comes from a plant source, such as olive oil or canola oil.
What about red meat? Well, the old pyramid says two to three servings a day. The new one says eat it sparingly, only a couple of times a week.
Put simply, the new pyramid from Harvard divides foods into good and bad. Good carbs are anything whole wheat or whole grain. Bad carbs are white, such as white bread, potatoes or rice.
Good proteins are fish, nuts and beans. Bad proteins are red meat. Dr. Willett says it's really a modified Mediterranean diet.
"There's not one single right diet. I think what we need to do is look at the Mediterranean diet to provide some possible options, some alternatives to our present diet," he says.
Just as the old government pyramid had its critics, this new pyramid is also coming in for criticism.
Some say it is too heavy in fats, even if they do come from olive oil. Others questions cutting down the servings of carbohydrates.
What it is doing is getting people to once again focus on what we eat, and how much.