There's been a very big environmental change over the past 20 years.
If you factor in body weight and body-weight increases, it appears that our per capita energy consumption rate has gone up 18% since the 1980s.
Many households have two working spouses, so there are time pressures that influence food purchases.
Food is now available 365 days a year, seven days a week, 24 hours a day. It's everywhere all the time.
