Lots of us have observed that foods that are good for us - broccoli and bean sprouts - don't trigger intense cravings. In the late afternoon, when my energy is low, I want a cookie or a piece of chocolate, not a green pepper.
Similarly, when I walk around the grocery store, I go through the meat and produce sections without feeling deep cravings for the food I see.
But when I get to the bakery, all bets are off, even if I'm not hungry.
These patterns of cravings are significant because what we eat affects our health so much. Obesity and diabetes are more and more problematic in the U.S., and all too many of us have a diet rich in french fries, doughnuts or soda pop.
Why is it we so intensely want what is likely to be bad for our health? Could it be there are strong biological reasons for the pickle we so often find ourselves in?
A recent piece from Oregon State University helps explain our pattern of cravings. It seems we have evolutionary adaptation to crave certain things. When we were hunter-gatherers in the wild, we had to decide what to eat and what to avoid. Our lives depended on our choices.
In the wild, sweet foods are generally good. They are safe to eat, and their calories help ward off hunger and starvation. When we were hunter-gatherers, we were on our feet essentially all day, every day, burning through the calories we ate. Some sweet fruit was good - good tasting and good for us.
Back in the old days, when we could hold off hunger by eating fat-rich foods, we also had reason to celebrate. The fatty portion of meat gave us a lot of calories, something we needed because we were burning a lot of "fuel" each day. High calorie food was to be welcomed in such circumstances, so fatty food was a good meal.
Now, however, our natural craving for sweets and fats gets us in trouble. I sit at a desk all day, yet I crave sweets and fats as much as my hunter-gatherer ancestors did during the Ice Age. It's easy for me to overeat, especially because there are chocolates kept in a bowl just a few feet from my desk.
When it comes to the battle of the bulge, a good test is to conjure up the image of a food and ask myself if I crave it. Sweet and salty foods are high on the list of what I crave, even when I've been eating three square meals a day and don't need more calories.
The Oregon State University publication points out "flavor" is a complicated subject. Only part of what gives a food its flavor is taste: sweet, sour, salty and so on.
Smell is also important: the smell of fresh brewed coffee comes close to driving me wild first thing in the morning. That brings up temperature, too, with the warmth of hot coffee being part of its appeal. Then there's the texture of a food like custard. Finally, some foods are spicy, a feature that makes them a favorite to some people.
We're all different, and our individual brains decide what foods we like. But most of us have a hankering for foods that are high in calories. Now that we can choose at the grocery store or the restaurant what we want to eat, rather than having to chase it down in the wild, we all too often end up with more calories than is useful for our health. They're good tasting calories, to be sure, but there are just too many of them.
But the good news from Oregon is that the way we perceive flavor is only partly instinct left over from our hunting and gathering days. It's also partly learned. It's certainly true that the first time I tasted coffee I thought it was terrible. Now I can't live without the stuff.
What we need to work on is retraining our senses to enjoy the foods that are really good - both good tasting and good for us. That may take more work than pulling up at the fast food outlet, but it's important labor that can yield rich rewards for our health.
E. Kirsten Peters, Ph.D, is a native of the rural Northwest who trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.