It’s no secret that as a society, Americans and other industrialized nations are getting heavier and obesity rates are skyrocketing compared to generations past. But have you ever wondered why this is happening?

It’s something I think about all of the time, and here is what I believe: Like obesity itself, there are multiple causes that together add up to create the crisis.

One factor is the increasing trend toward eating out at traditional or fast food restaurants instead of eating meals at home. Likewise, when we do eat at home, it’s more often a pre-made, processed convenience meal than something prepared from scratch. In both cases, these types of foods often contain far more fat, calories, salt, and sugar than meals prepared the old-fashioned way.

In fact, if you were able to peek into the kitchens at most restaurants, what you would find may just spoil your appetite! There’s a reason these foods taste better than food cooked at home and the reason is often because the seemingly healthy stir-fried veggies were cooked with a half stick of butter, the grilled chicken was dipped in oil first, or the egg white breakfast burrito was fried in pure bacon fat!

Restaurants are also serving much larger portions of foods than they have in years past, hoping to out-serve their competitors and at the same time justify the higher price of eating out. In some cases, a single meal can contain 2,000 calories or more than someone should eat all day, much less in a single meal.

Our tendency to choose sedentary activities like eating out or watching movies instead of more physical activities like going for a walk in the park or playing sports is also contributing to the obesity epidemic. Today many people spend most of their day sitting at a desk, followed by spending their free time sitting in restaurants, movie theaters, or on the couch. Unlike when we were children, activities like video games and surfing the Internet now replace old pastimes like playing tag or roller skating around the neighborhood.

Our commuter society is also playing a role. Today most cities and communities are designed so that you have to get everywhere by car, bus, or subway rather than by biking or on foot. Many people spend an hour or more in their cars going to and from work every day, time they could otherwise spend being active.

Likewise, the way we live has changed over the past few decades but our genes have not. In the no-so-distant past, humans had to spend most of their waking hours engaged in physical pursuits just to survive, and one had to expend as many calories either hunting or farming their food as the food itself contained!

Few people live this way today. Instead, most people trade their time and mind for money they earn at a sedentary job that they then use to buy the plentiful and calorie-dense foods they eat and to pay for their shelter and basic necessities. For example, chopping firewood, which burns about 400 calories per hour, has been replaced by flipping a switch, which takes hardly any effort at all.

So if how the world is changing is causing the obesity problem, what’s the solution? Start by doing all you can to counter the trend. Cook meals from scratch and at home. Pack your lunch. Limit the number of times you eat out every week to two meals or less. Park as far as you can from the door in parking lots, rather than in the closest spot. Take the stairs instead of the elevator. Skip the movie this weekend and go for a hike instead. All of these small changes can really add up!

In short, society isn’t changing fast enough or in the right direction to prevent obesity, but you as an individual can make the changes needed to lose weight and keep it off.