More than a quarter of all adults in the United States are obese, and that number is steadily growing.
Barry Popkin, a distinguished professor of nutrition at the University of North Carolina at Chapel Hill, and coauthor Kiyah Duffey analyzed data from U.S. food surveys collected from adults from 1977 to 2006.
Their new study shows people in the U.S. consume 570 calories per day more than they did back in the 1970s -- roughly a pound a week!
Health experts say that one problem is portion sizes.
"We're used to seeing more on our plates. Therefore, we eat it. When it's in front of us, we consume it," explained Felicia Stoler, a registered dietician.
Even worse than the amount of food on our plates is how often Americans are eating.
"We have food everywhere. They're at gas stations. They're at movie theatres. We've got it at coffee shops," Stoler explained.
Snacking accounts for more than 25 percent of an Americans average calorie intake. Sugary drinks make up for 50 percent of those snacking calories.
In 2006, the time spent snacking averaged about 15 minutes per day. In 2008, that number doubled to almost 30 minutes a day.
Nutritionists say that Americans are choosing foods more for flavor than nutritional value. Such junk food leaves you hungry again after only an hour or two.
Experts warn there's no easy fix for Americans poor eating habits. They said it's going to take a little extra willpower to resist food that is all too easily accessible.