If you’ve ever watched Sesame Street, you may remember the song about categories: “One of these things is not like the others. One of these things just doesn’t belong.” That song ran through my head when I looked at the USDA’s My Plate food group system, which features vegetables, fruits, grains, dairy, and protein. One of the foods groups isn’t like the others and just doesn’t belong. Can you guess which one?
If you guessed protein, you’re right! Four of the food groups represent a type of foodstuff, but protein is a nutrient. Foods from all of the other groups also contain some protein.
People often have to sort things into categories for various purposes. The categories that you create depend on what goal you are trying to achieve. If you are doing your laundry, you first sort your clothes into three categories. You can wash some things in the washing machine. You have to wash other things in the sink. Still others have to go to the dry cleaner. You probably sort the machine-washable clothes by whether they go in the regular cycle or the delicates cycle. Unless you don’t mind if your whites turn pink, you should also sort your machine-washable clothes by color. In other words, all of the clothes get sorted into a particular category according to how they get washed. Of course, you’d sort your clothes by different criteria when you are deciding what to wear. You might have some outfits that you wear to work or school, others that you might wear to a nightclub, and still others that you might wear while painting or gardening.
In contrast, the My Plate food group system isn’t a good categorization system for any purpose. Four of the groups represent a type of foodstuff: fruit, vegetables, grains, and dairy. The fifth group represents a nutrient: protein. Why do four of the food groups represent foodstuffs but the other one represents a nutrient that is easily supplied by three of the other food groups? It makes no sense. If you think about what goes into the protein group, the category makes even less sense.
The protein group is the old “meat” group from the Basic Four Food Groups in disguise. It consists of meat, eggs, fish, and legumes (beans and peas). Yet there’s no good reason to put legumes in the same group with meat, fish, and eggs. Meat, eggs, and fish are all animal tissue. Therefore, they all contain fat and cholesterol but no fiber or carbohydrate. In contrast, legumes are plant tissue. They contain zero cholesterol, and most contain only trace amounts of fat, but they have plenty of fiber and carbohydrate. Like the animal-source foods, beans and peas do contain a lot of protein, but protein deficiency is simply not something that people really need to worry about. There’s no need to encourage people to eat high-protein foods, so there’s no need for a “protein” group.
I would never put legumes in the same category as meat, fish, and eggs. The reason is simple. People would be better off if they didn’t eat any meat, fish, or eggs at all. Eating even small amounts of those foods increases the risk of death from chronic disease. In contrast, the world’s healthiest populations tend to eat a lot of beans. So maybe the children’s song is right: “Beans, beans, good for your heart….”
At first glance, the USDA’s My Plate system looks a lot like the Physicians Committee for Responsible Medicine’s Power Plate. However, the Physicians Committee for Responsible Medicine designed the Power Plate to promote human health, not to sell food products. The Power Plate includes only four categories of food: fruit, vegetables, whole grains, and legumes (beans and peas).
The PCRM’s Power Plate doesn’t include a separate category for protein because you can easily get enough protein by eating vegetables, grains, and beans. The Power Plate doesn’t contain meat or dairy foods, because those foods increase the risk of serious health problems, such as obesity, heart disease, autoimmune disease, and cancer. The Power Plate also excludes refined foods, such as olive oil and corn syrup, which merely provide empty calories.
Wild gorillas meet their nutritional needs by eating practically nothing but vegetables and a little bit of fruit and a few nuts. These foods provide all of the essential nutrients except for vitamin B12 and vitamin D. Vitamin B12 comes from bacteria, and the body makes its own vitamin D when bright sunshine hits the skin.
Gorillas mainly eat leaves. Leaves provide plenty of protein, as a percentage of calories. However, wild gorillas have to spend about 8 hours a day eating, just to get enough calories. If you don’t want to spend all day eating leaves, add some starchy foods to your diet. That means whole grains, legumes, and starchy roots and tubers, such as potatoes and sweet potatoes. These starchy foods will fill you up but will help you stay slim and healthy.
Note: Ontology is the branch of philosophy that deals with how to name things and how to sort them into categories. There are several important rules of thumb for judging a categorization system. One is that the system allows each item to be categorized into exactly one classification. A categorization system that meets that criterion can be described as MECE, which stands for mutually exclusive (i.e., the categories do not overlap), collectively exhaustive (everything gets classified). Another criterion is reliability, which means that different people would give the same item the same classification. Yet another criterion is validity. The classifications have to be useful for some practical purpose. In my book Don’t Feed the Narcissists! The Mythology and Science of Mental Health, I explain that the second edition of the American Psychiatric Association’s Diagnostic and Statistical Manual (DSM-II) was unreliable. It was therefore invalid. (An unreliable classification system is automatically invalid.) I also explain that there are still debates about the reliability and validity of various psychiatric diagnoses.