One day recently, a friend complained in the dining hall that the salad was not good. “Then why are you eating it? Just leave it,” I responded. “No, I don’t want to waste food,” he told me. His simple answer struck me.

Wasting food is an offense of which I was often — and still occasionally am — guilty. Unfortunately, I am not alone.

Yale students frequently waste food. We habitually put more food on our trays than we can possibly eat; then we leave it, without feeling any guilt whatsoever. The worst thing we do is go for seconds without having finished what is already on our plate. After we have had our mini-feasts, we put our trays away. The leftovers obviously go to the trash.

Our reasoning is that as we were the ones who paid for the food, it should concern no one what we actually do with the food. This logic makes sense to an extent: People have the right to do whatever they want to do with their belongings. Food is simply another good that people buy with their money, and if they do not like it, they have the right to throw it away.

But there are two problems with this argument: one economic and one moral. The economic problem is that the price we pay for our food does not include the social cost of producing that food. For example, when we buy a tuna sandwich, the price includes only the cost of producing the sandwich — the money paid to the fishing company that caught the fish, the cost of transporting the fish to New Haven, the costs incurred at the sandwich bread factory, and so on.

What the price tag does not include are the externalities: the social costs the sandwich-maker does not and cannot account for in its pricing strategy. Damage to the environment by transporting the materials over thousands of miles, low wages paid to fishermen who caught the fish, depletion of fish due to overfishing and other such hidden costs are examples of unaccounted costs. Thus when we throw a sandwich away, we incur all these social costs for no reason.

There is also the moral problem with throwing away food. Wasting food at a time when millions of people around the world do not have sufficient means of feeding themselves or their children is a terrible thing. Would it not have been better to donate our food to people who need of it, instead of wasting it?

But donate what, uneaten tuna sandwiches? The idea is not so much to start donating perishable food products, but rather not to buy these products when they are not required. This is a lesson that would have to be learned not only by college students who throw away food in their dining halls but also by the American public at large. Wasting food is a national scourge. According to a University of Arizona study, food worth $100 billion is wasted annually in the United States. That is more than the combined GDPs of 20 of Africa’s poorest countries. An economist might describe this as an inefficient distribution of resources. A humanist might label this a gross injustice.

On a personal level, we should try our best not to waste food. This is what we can practically apply in our daily lives, starting from the dining halls. Take small amounts of food on your plate at a time. Go for seconds or thirds if need be, but finish the thing you have on your plate first. If trying a new cuisine, it does not hurt to put a tiny amount on your plate to test it first. In fact, we should not only be careful ourselves, but also remind our friends to not waste food. Not wasting food does not take much effort, but it makes a big difference to the world around us.

Syed Salah Ahmed is a sophomore in Saybrook