Are Prepared Foods Making Us Fat?

Americans are replacing home-cooked meals with prepared foods--does that lead to obesity?


Photo by axio/Flickr CC

Michael Pollan's article on how American cooking "became a spectator sport" should be a wake-up call to young adults, particularly young adults with children. As the article points out, Americans are fascinated by shows about cooking, but show little interest in cooking themselves; instead they are buying more and more fast food and prepared or semi-prepared meals.

The author ties the decline in cooking to more women working outside the home, extensive marketing by food companies to change the social norm so that it becomes acceptable to outsource some or all food preparation for a meal, and the introduction of technology (large freezers, microwaves) that makes it easier to prepare meals. He also ties the rise in purchasing prepared food to the increase in obesity.

As an obesity researcher, I think all of these arguments make sense, but I also know that the data are lacking to make draw firm conclusions. It is true that during the past several decades there has been an increase in the amount of prepared food consumed either at home or in restaurants, and a staggering rise in obesity among children and adults .

However, just because two trends occur at the same time does not mean they are related. What is needed are studies that track people's dietary habits and weight over time. So far these studies have shown that fast food intake is tied to weight gain. But studies are lacking on the association between other types of prepared foods and weight gain or obesity.

It is a topic I am pursuing, and I continue to be surprised at the dearth of studies. Barbara Rolls and colleagues have shown that portion size influences caloric intake; because prepared foods are often served in large portions, it seems likely that they promote excessive caloric intake and weight gain. But we need more research to make the connection between prepared foods and weight gain.

Further complicating the picture is the huge number of foods that fall under the term "prepared" or "semi-prepared"--and because people are cooking less and less, their very idea of what a prepared food is may be changing. Putting pasta sauce from a jar on cooked spaghetti may or may not be considered using prepared foods, depending on the perspective of the "cook."

Further complicating things is the many foods like macaroni and cheese that can be made at home either from scratch or from a mix--or bought as a ready-to-eat dish. Unfortunately, most epidemiologic studies that follow people's diets and weights over time don't collect the details that would allow the authors to differentiate between what was made from scratch and foods at least semi-prepared outside the home. This may explain why there is so little research on the association between prepared foods and obesity.



Even if we do not yet have studies connecting the reliance on prepared foods--other than fast food--to weight gain, there is a lot to support the idea that the two are related. One of the most powerful ways people learn is by observing others. In the past, not only did children, particularly girls, learn to cook from their mothers, but also they learned the general steps involved in cooking. That includes learning about the ingredients used to make meals. Relying increasingly on prepared and semi-prepared foods can lead to raising generations who have, at best, a vague idea of what they are eating, and set them up for eating a diet too high in calories and too low in fiber.

For those of us trying to prevent or treat obesity, the reliance on prepared foods is also of concern because getting people to change what they eat is much harder if they don't cook in the first place. It is a much bigger change to ask someone to start making their own dinner from scratch than asking someone who already cooks to change the number of tablespoons or the type of fat they use in their cooking.

We have a ways to go before we better understand what motivates someone to cook from scratch versus with some prepared ingredients versus buying prepared meals, and we need studies that link these types of food preparation to obesity. In the meantime, I think we should still encourage men and women to get into the kitchen and take greater control of what they eat--and limit dietary outsourcing.

This is one of the priorities I've made in my own family, and it's already paying dividends. Recently, when our babysitter asked my daughter, Sofia, what she wanted for lunch, Sofia opened the cabinet and pulled out olive oil and garlic. She knew that the first step in most things I cook involve sautéing garlic in olive oil.

When Julia Child came on the air, she opened a door for many women. She presented a range of recipes that at that time were "exotic", and showed how women could make them at home. But more than showing people how to cook, Julia showed what it was like to love food and cooking. We must remember, though, that in Julia's time many women had to cook, and didn't have all the prepared options that exist today. Again: showing someone who knows the basics of cooking how to branch out is very different from showing someone who doesn't cook at all how to make an entree. It's not realistic to expect Americans to suddenly give up all the convenience products they consume, so we should try to sell the idea of cooking one to two simple meals a week and how to enjoy making those meals.

Of course, it's hard to market an idea that doesn't have a food company with large amounts of money behind it. So I think we need to market the idea that Americans are being taken advantage of: companies are now trying to get them to pay too much for prepared foods. Nobody likes to be taken advantage of. Now, when people are being more careful with their food spending than they've been in decades, we have a unique opportunity to sell that idea. We should take it.